January 2002 Forecast Outlook, Discussion & Report Page
|.||.||February Forecast Outlook, Discussion and Report page|
|31||Andrew McDonald||Today: Temperatures across the NE
of the state are hitting the low-mid 30's as we speak and should probably get close to (if
not slightly above) 36C near the border over the next few hours. Dew points are currently
sitting between 11 and 14C across the eastern and north eastern areas and the soundings in
both Melb and Wagga show nice moist PBL's of about 10-11C up to about 900mb. Given that
there are currently showers/weak storms on the ranges just NE of Albury in the Tumbarumba
region, I'd expect thunderstorm activity to extend down across the Victorian alps over the
next few hours. There are also a few showers/weak storms popping up closer to the axis of
the developing trough which at the moment looks to run just west of Griffith in NSW down
to about Benalla. Temperatures in the Griffith area have reached about 36C with DP's
ranging from 14-16C so this convection kicked off probably by the convergence closer to
the trough is not surprising. The trough itself could be an area to watch this afternoon
as the temperatures get warmer further S (nearer to Vic) and the moist air from the
coastal areas is advected across the ranges towards the developing trough. Convection
should spread slowly southwards along this trough line giving places off the ranges the
chance of a late storm (to the W and SW of Albury). Although likely to be very slow moving
given the complete lack of shear, some storms could produce some very heavy rainfall and
maybe some strong winds. I'd think that small hail to about 1cm is possible off the ranges
but the alpine areas could see some slightly larger hail (say to 2cm) in a storms due to
the elevation and in essence the reduced freezing level. Interestingly, AVN has a 300mb
cold pool sitting NW-SE across Melbourne this afternoon which should causing some decent
destabilization (of about 1-1.5C) over the next 6 hours in the N and E parts of the state
and although weakening slightly, it could see storms continue into the evening and after
dark. This cold pool could potentially see some quite large storms developing with
estimated tops of 37,000-40,000ft possible. Further to this, a weak 500mb trough persists
through central areas throughout the period (Thurs - Fri) which has temps of about -11.5
to -12C. Given the complete lack of shear over the NE today (and S NSW for that matter)
storm movement will most likely be due to propagation than anything else.
Tomorrow (Friday): Tomorrow should prove to be an interesting day - there will be something to be learned from tomorrow. Instability across the state should increase significantly as the trough deepens through western Victoria. My biggest concern tomorrow is the upper level ridging forecast to push into the western parts as the 300mb trough moves off to the east. Upper levels look to warm by as much as 4C in some places which could see storms topping out at quite low levels. The 500mb trough mentioned above is quite deceptive and those who follow the LI's a lot may see how volatile this index can be. LI's of -5 to -6 are progged by AVN in an area around Colac tomorrow but this area is seeing strong upper ridging (above 500mb) at the same time. So even though up to 500mb the atmosphere is quite unstable, above that, the airmass seemingly stabilizes significantly - to the point where only showers and weak storms may occur. The NE-N'ly flow into the trough should bring in additional moisture across the entire state and temperatures are forecast to reach the low-mid 30's. Given the 850mb temps of 16-19C the cap should be of a decent enough strength to keep things quiet until mid-late afternoon although as per last week the first places likely to go will be the ranges and also close to the trough. Note that convection could become widespread if temperatures across the state are slightly higher than forecast. Again shear will be very weak although the small amount there is should see storms move in a SE'ly direction (although propagation of storms could see them move all over the place so don't be surprised if they move a tad backwards or sidewards...hehe). I will probably be hanging around Melbourne until at least lunchtime tomorrow before making my decision as to where to head so I'll do some more notes tomorrow morning.
Saturday: Well - now that this is so long I'll leave Saturday until tomorrow morning or tonight. Interestingly though, some of the models hint at the trough being quite slow moving and giving parts of Victoria a chance at storms again (namely north cent, northern country, north east, alpine and eastern districts). More detail to follow later on this.
|31||Clyve Herbert||A somewhat interesting cloud area just north and northwest of the Kimberley region of WA. An area of surface enhanced convergence has been present over the far north of WA for a few days and now appears to have moved offshore, upper divergence is rather weak but some outflow characteristics can be seen, seems to be moving west southwest|
|31||.||High moving generally SE over Tasmania,
extending a weak ridge along the NSW coast. Weak trough remaining through inland
Queensland, NSW (west of the ranges) and extending into northeast Victoria during Thursday
& triggering scattered storms in those areas. Area of low pressure just off the
coast of SE Queensland bringing widespread coastal showers with some heavy falls expected
along the northern NSW coast & southern Queensland. Area of generally low pressure
across the north of Australia with increasing seasonal storm activity throughout.
Moist mid-upper infeed from the Indian Ocean coming onshore in the Kimberley & Pilbara
regions which will increase the available moisture over WA. Mid-upper level low continuing
to sit along the WA coast with a strong moisture plume originating from ~27S 75E feeding
into the area triggering storms in the west & the Gascoyne. Eastern central WA &
northern SA along with southern NT will have scattered storms during Thursday. Front
passing through the western Bight area interacting with WA heat trough and dragging the
southern part eastwards - the trough will trigger storms through the day as it moves east.
The high will direct SE winds across South Australia with patchy cloud increasing as the
trough moves east but little activity is expected through Thursday. Warm on the
coast to hot in inland Victoria with increasingly unsettled conditions, spreading
from the NE ranges on Thursday, to include western areas later Friday. Instability
in west & central districts of Victoria on Thursday may be dampened down by a weak
upper ridge moving across the state. Tasmania to remain generally fine through Thursday.
Risks: the area around Derby in Western Australia should continue to be watched for the possible development of a tropical low
|30||Andrew McDonald||Tomorrow has the potential to be quite
good in NE VIC/SE NSW with AVN progging some very nice instability but a complete lack of
shear will see storms being quite pulsy and most likely being severe for short periods of
time. Cool upper levels may allow for some hail to develop (to about 2-2.5cm at best) but
the biggest threat tomorrow afternoon and evening will be very heavy rainfall leading to
flash flooding (given the slow movement likely with storms tomorrow) and also damaging
winds in downbursts. 850 temps are progged to be about 18-19C in the area tomorrow,
providing a nice cap. The ranges should go up by mid afternoon and anything developing off
the ranges will probably pop after 4pm.
Friday is looking interesting. The upper level trough (as in 300mb) moves off to the E of the state with moderate upper level ridging pushing into the west of the state. The 500mb trough is progged to be sitting over the W of the state (part of the reason why the LI's are -4 to -5 out that way no doubt). This is OK but it could mean that storms will be quite low topped (being 27-30,000ft) in the western parts of the state. Shear is marginally better in the W half of the state on Friday so storms should actually move, unlike Thursday...hehe. Given that moderate instability is progged for Melbourne as well on Friday and the upper level temps are more favourable over this area I am currently thinking that I wouldn't get too far away from here. Of course this will depend a lot on what happens tomorrow and also what Friday morning shows (in terms of moisture, cloud, etc). More detail for Friday will follow tomorrow.
|30||.||Baric ridge running south
of Australia through the Bight and through Bass Strait to New Zealand. Ridge extending
inland from the SE corner of NSW, with a weak trough extending from the heat low in
western Queensland through central NSW and deepening to Victoria. Occasional showers along
the NSW coast in the onshore SE winds. Area of low pressure across the northern part
of the continent triggering scattered storms across the country, with the WA heat trough
remaining just off the coast on Wednesday. Middle-level low over the same general
area triggering showers & storms through the Gascoyne, Goldfields and northern part of
the SW. Moisture plume from the area of intense convection SW of Sumatra is feeding
into this area and should move southeast towards Victoria over the next few days.
South Australia should be fine during Wednesday with increasing cloud later in the week
& becoming unsettled. Victoria should remain mainly fine for the Wednesday with
temperatures mild on the coast & warmer inland. Approaching frontal system will
trigger showers over Tasmania as it slips past.
Risks: 2 areas should be watched for possible developments - the area around Derby in Western Australia and the cloudband moving westwards just to the north of New Zealand, which may wrap around the low pressure area in the Coral Sea.
|29||Andrew McDonald||...onto this
week(end). I don't think we'll see anything too close to Melbourne
on Thursday. The weak front coming through on Wednesday will stabilise
things in the south a bit. I think Thursday will be best in the NE parts of the state - perhaps Albury - Bright area if anyone was looking
at chasing. I can do a more detailed f'cast later in the week (like
tomorrow) when we get a better idea of what's happening. Friday looks to be quite similar to last Friday with a trough deepening
over the W of the state giving moist NE'ly sfc flow across
much of the state. The remnants of an upper trough will be
sitting across the eastern parts and a weak upper ridge will
be across the western parts. The BoM are going for storms on
the ranges and also near the trough which is a fair call IMO but I think anywhere E of the trough will stand a chance. Again shear will be
very weak on Thursday and Friday so storms should be slow moving.
Saturday is a lot more interesting. The trough is forecast to deepen further and move across Victoria bringing widespread showers and storms. Shear should increase throughout the day as a beefy upper trough pushes in from the W. I doubt Sunday will have anything as the models have the trough moving off to NSW by early Sunday so unless you want to head into Sydney and the Hunter on Sunday you might want to give it a miss.
|29||.||High ridging through Bass Strait. Trough moving eastwards through NSW & Queensland. Coral Sea surface low pressure forcing southwards towards the Tasman Sea. High near NZ maintaining a ridge onto the NSW coast with the aid of the high edging around the corner from Bass Strait bringing isolated coastal showers, with Queensland remaining under the triple influences of the inland trough, increasing ITCZ activity in the north and the Coral Sea low. SE flow across much of southern & coastal Queensland, warm to hot inland with scattered storms through the north, central & southern inland. Scattered storms also in northern NSW as the trough moves east. Seasonal storm activity continuing over parts of the Top End and much of the Kimberley. WA heat trough starting to edge eastwards to lie just inland along the coast Tuesday. Upper trough off the WA coast, almost stationary on Monday, will interact with the surface trough, triggering scattered storms, with some heavy falls possible across much of the central & western parts of the state with hot northeasterlies except in the far SW. Mild E - SE flow being directed over South Australia and Victoria courtesy of the high in the Bight as it ridges east. Possible isolated storms along the northeast ranges in Victoria in the southern part of the inland trough. Tasmania should remain mild under the influence of SE-SW winds with isolated showers and drizzle mainly in the south.|
|28||.||High in the Bight ridging
through Bass Strait. Ridge from the high in the NZ area reaching to the central NSW coast
with the Queensland coast coming more under the influence of lower pressures in the Coral
Sea with SE-NE onshore winds. Trough continues to move slowly eastwards triggering
isolated storms through central NSW & SW Queensland during Monday. Warm to hot inland.
Seasonal storm activity increasing over the north of Australia, with showers & storms
becoming more frequent over the Gulf &Top End than for the past couple of weeks.
WA trough extending southwards along the coast. Temperatures over the state
remaining high with isolated showers & storms in the moist air from the Indian Ocean,
mainly between latitudes 22S and 30S as well as the tropics. SW flow onto the coast of
South Australia keeping temperatures moderate in showery conditions turning more SE as the
high ridges south of the state. Possible isolated storms in the NE. Victoria should
experience scattered showers in a mild SW stream as the trough moves through to the east
of the state & the surface low slides SE to the southern Tasman. Tasmania should
see increasing rain periods as the low passes the state, decreasing through tomorrow.
Risks: Upper cold pool in the Bight moving NE looks to move towards western NSW during later during the next 48 hours. Intense monsoonal activity west of Sumatra should be watched for the possible development of strong outflow towards WA over the next 72 hours.
|27||.||Moist onshore winds will
maintain moisture levels along coastal NSW through Sunday with showers occasionally
extending to the ranges. Trough moving into the west of the state will trigger
isolated storms as it moves east. Surface ridge along the Queensland coast should move
slightly inland on Sunday & maintain SE onshore flow with coastal showers decreasing
through the day. Coral Sea low should remain slow moving. Trough moving into the SW of the
state during Sunday will trigger isolated storms there. Increasing monsoonal
activity with the ITCZ becoming more active across the tropics, with scattered storms
throughout the northern parts particularly in the west. WA heat trough moving west to be
located along the coast, directing hot northeasterlies over much of central & southern
inland WA, while the ridge along the southern coast will maintain a cool SE flow with only
isolated drizzle on the coast. TC Eddy is directing an unstable flow in the mid
& upper levels into the west of Australia and there is an upper trough approaching SW
WA. Much of SA will be under the cloudband from WA during Sunday which will
help to moderate temperatures & may result in some light falls of rain through the
state as well as isolated storms which will move eastwards during the day. Trough moving
east will swing the winds from NW to SW. Weak area of low pressure associated with
the deepening trough will continue to slide SE through Sunday towards Tasmania, helping
trigger unsettled weather in the western parts of Victoria & Tasmania with scattered
thunderstorms near to the trough & patchy rain mainly over southern & western
parts of both states. Warm to hot in Victoria before the passage of the trough, with winds
shifting milder SW as it crosses the state.
Risks: Moist infeed from TC Eddy in the Indian Ocean may begin to reach SA & Victoria over the next day or two, with the possible development of a middle level vorticity centre over central South Australia which may prolong showery conditions with isolated storms particularly in SE South Australia & Victoria early next week...this is a definite 'maybe'.
|26||.||High in the Tasman Sea directing a weak
ridge up the east coast on Friday which will weaken & move inland during Saturday
helping to shift the trough westwards away from the coast again. Coastal showers are
likely in a NE flow along the NSW coast with a chance of thunderstorms in the north. Coral
Sea low maintaining its slow southwards movement & directing a showery SE flow onto
the Queensland coast. Upper trough over Queensland moving east towards the coast
during Saturday triggering occasional storms along its length from the NE of NSW to the
southern tropics. Fine and hot west of the trough, milder to the east. Low pressure across
the top of the continent with more frequent seasonal storms in the west. High ridging
towards WA will edge southwards towards the Bight as temperatures increase during
the day, and will direct S - SE winds onto the southern coast & adjacent areas keeping
temperatures mild with occasional showers. West Australian surface trough deepens
with temperatures rising inland. The trough extending from the tropics to the Bight
through South Australia will move east swinging winds to the NW over SA during Saturday.
Unsettled conditions in both SA & Victoria associated with the eastward movement of
the trough. Victoria can expect isolated storms, mainly along the ranges again on
Saturday with activity becoming more likely in the west near to the trough on Sunday.
Moist NE airflow being maintained across the state, shifting to NW closer to the trough.
Tasmania will also experience isolated storms, particularly to the west.
Risks: outflow from TC Eddy in the Indian Ocean will flow into the Australian region increasing moisture in the middle & upper levels over Western Australia & towards the SE of the continent during the latter part of the long weekend. Watch for the possible development of a mid level vorticity centre over the next 24 hours in the southern WA / western Bight region which will move southeast later in the weekend.
|25||Andrew McDonald||Well, as you have no doubt read the BoM
are banking on the trough to stall in Vic from today until Monday. They are basing this
totally on EC as all the other models (MRF, NGP, GASP and AVN) are pushing the trough
through on Sunday - and personally I cannot see the type of system progged for Sunday
stalling as per EC.
Today: The upper trough is sitting just to the east of Melbourne giving us some quite nice upper level temperatures (-13.5C at 500mb and -40.5C at 300mb) hence the aviation forecast including hail. Moisture is very nice right across Victoria at the moment with DP's in the 13-17C range. I had a quick look at our sounding from last night (with -2.7 LI's on it) and if you plot 33/14 it comes up with a LI figure of about -5 or so....which is quite nice. Shear today is not overly great. The directional shear is very nice but the speed shear is seriously lacking. Sfc to 850mb winds are NE-N'ly at about 10knts, 700mb winds are NNW'ly at 15knts, 500mb winds are WSW'ly at 15knts, 300mb winds are SW'ly at 35knts, 250mb winds are SSW'ly at about 45knts. We should see some very nice storms today with the chance of severe storms with heavy rain likely (given the high DP's) and strong winds possible. There is also a very slight chance of large hail but i'd expect nothing over 3cm. LAPS has some weak convergence along the trough later today out to the west of here running N-S along a line of about Camperdown - Ararat - Swan Hill and there is likely to be some nice convergence along the coastal and bayside areas from seabreezes. These boundaries could provide some added lift to kick off convection as well as added shear to storms, perhaps taking them over the edge from garden variety to severe. (Don't be surprised if storms ride along these seabreeze lines as well.) I wouldn't expect any storms W of this trough/convergence line in the western part of the state (so if you are W of the trough, get E).
Saturday: Upper level ridging will supress convection a tad meaning that storm are more likely on the ranges. Severe storms are less likely due to warming in the upper levels over much of the state. Of interest is the weak 500mb trough forecast by AVN to push into the W parts of the state (moreso the SW). I won't go into too much detail for Saturday just yet - I'll wait until tonight or tomorrow morning.
Sunday: The models all agree that the trough will deepen and lie across Victoria on Sunday with the chance of storms in all districts. An upper level low and associated trough is going to push into the state so shear should improve somewhat as should upper level temperatures. The only problem here may be cloud.
Monday: As I mentioned above, the BoM have based their forecast for Monday solely on EC. As much as I'd like this to happen (as I can actually commit to a full day of chasing Monday) I cannot see this system stalling to the extent that EC has. I'll comment further on this as the other models come into play......
Well - the BoM have come to the party now and have the trough coming through with showers and storms in the NE only on Monday
|25||.||High moving SE of Tasmania towards
New Zealand directing a humid NE flow over SE Australia. Low in the Coral Sea
continuing to move SW towards the coast. Heat low in western Queensland at the
northern end of the broad trough which is expected to remain over eastern Australia for
the next couple of days. Trough continues to edge slowly westwards except in the far
north. Onshore SE-NE winds feeding into the trough will maintain high moisture levels
while temperatures continue to increase - scattered storms, some severe, are likely west
of the ranges in NSW (particularly) & Queensland, extending into Victoria mainly in
the northeast. Upper trough deepening over inland Queensland & moving east towards the
coast will lead to increasing shower and storm activity though to the weekend with
moderate to heavy falls possible. Seasonal storm activity becoming more widespread with
increasing convergence along the ITCZ, continuing more frequent in the west.
WA heat trough moving east triggering isolated storms while conditions will remain hot
& fine inland to its west. Fine over the SW of WA as the high ridges slowly east into
the Bight. Trough moving through South Australia may trigger isolated storms in the west
with the windchange. Temperatures increasing with the generally NE flow through most of
the SE of Australia. Isolated storms along the Victorian ranges mainly in the
northeast on Friday afternoon under the influence of the trough, but possibly extending
westwards along the ranges. Tasmania should experience a few showers, variable winds
& mild temperatures under the influence of the high in the Tasman.
Risks: The first warning (severe weather) was issued for the Coral Sea low mid afternoon (24/1/2002). The low is identifiable to the mid levels with an upper high over the area lending divergence aloft. Trough off the NSW & southern Queensland coast moving towards the coast may trigger some heavy falls.
|24||Andrew McDonald||BoM are going for storms on the central
and eastern ranges tomorrow and Saturday. This is an interesting forecast and I wouldn't
be surprised to see this change a tad to mention that storms are possible in the E and N
suburbs of Melbourne on both days. AVN, GASP, LAPS and TLAPS all have instability
extending down well into the metro area. The inland trough looks to be slightly
ill-defined over the next few days (inc today) which means the ranges will probably be
required to give additional lift to trigger the storms - at least until the front/trough
moves in from the W on Saturday.
Given the current progged steering flow on Friday, storms are going to be quite slow moving with 0-6km shear of just 10-15knts. Steering flow is from the NW-W and the 300mb jet of just 25-30knts (from the SW so anvils should stream to the NE) so storms would be expected to move SE-E and given that, the BoM may not be expecting storms to move off the ranges into the suburbs. Unfortunately, this lack of shear is associated with an upper trough sitting over the E half of the state and lapse rates will be quite good with sfc temps forecast to reach the low 30's, 850mb temps of around +17C, 500mb temps of -12 to -13C and 300mb temps of about -40C (giving a 0-6km lapse rate of about 6.7C/km). There is some moisture across southern and eastern Victoria at the moment and given the current moist easterly airstream across the E coast, the DP's should remain fairly constant in the low-mid teens until the front on Sunday.
Saturday's shear is interesting depending on the area targeted. Instability is forecast to be best in E Vic over the ranges but it extends right across central Victoria with another area of slightly greater instability in W Vic. Over the E ranges 0-6km shear is about the same as Friday with 10-15knts. 300mb flow is up a bit to 40-50knts over the E half of the state as the upper level trough is squeezed out further to the east. Because of this the upper levels warm slightly but this should be offset somewhat by the warming in the lower layers. Low level lapse rates will be slightly higher but upper level lapse rates will be weaker. Again moisture should not be a problem.
The area of instability over W Vic is coupled with some nice convergence along the trough moving in from the W. Moisture again should not be a problem with N to NE'ly flow feeding in from the very moist air across the E parts of NSW. Shear is quite a bit nicer in W Vic than in E Vic with 0-6km shear of 25-30knts. With N-NE'ly winds from the sfc to 850 of about 10knts, 700mb winds of 15knts from the NNW, 500mb winds of 30knts from the WNW and the 300mb winds of 40-45knts, storms should be a bit more organised than Friday. If storms can penetrate a tad higher there is a juicier 60-70knt jet at 200mb. The trough should prove an adequate trigger for lift in this region meaning that ranges should not be required over the W parts. Low level temperatures are forecast to warm up a bit with sfc temps forecast in the mid-high 30's and 850 temps are forecast to warm to 18-20C across the western areas. This is quite warm and could mean some nice capping for the area. A nice 500mb trough is pushing into the western areas on Saturday afternoon dropping 500mb temps over the region by 1-2C from Friday to -12 to -13C. 300mb temps warm slightly from Friday as the upper trough moves off to the east but this shouldn't be too much of a telling factor.
If I was to choose my target areas based on this morning's model runs I'd be looking at the eastern ranges in the area bound by Albury - Benalla - Bright/Mt Beauty for tomorrow (noting that the ski resorts have great views and increased chances of hail if you are lucky to score a direct hit from a decent storm). For Saturday I'd be looking at playing the trough. The models are a bit variable as to where the trough will lie at prime time (mid-late arvo) but I think the sfc convergence, the shear and the instability combination will provide for more organised and photogenic storms than the ranges storms. Based almost solely on AVN at the moment I'd be looking at the area bound by Bendigo - Horsham - Ararat - Camperdown - Geelong. This is a large area and I'd narrow it down on the day depending on cloud, temperatures, moisture and most importantly, the positioning of the trough.
Sunday is a different story all together....the models are all varying about when the trough will move across Victoria - some even stalling it across Victoria Saturday, Sunday and then pushing it out on Monday (note that the BoM were heard on the radio stating that it could be stormy for the next 4 days being Fri, Sat, Sun, Mon - implying they feel the trough could hang around until Monday). I won't be making my mind up about this until closer to the time so I'll leave it at that for now. I'll add to this tomorrow, and again Saturday morning (if I have time). As luck would have it my chasing time is *very* restricted this weekend (inc tomorrow).
Incidentally, the BoM have gone for a *chance* of severe storms today in an area bound by Echuca - Yea - Warburton - East Sale - Orbost - the border. Moisture levels are expected to be high enough today to produce very heavy rainfall from slow moving storms. Temperatures across the NE are pushing into the low 30's already with the trough sitting just E of Managlore - Kyabram. Anywhere E of this trough is a chance today. Radar shows some showers in SE NSW at the moment and these should extend down into the ranges over the next few hours with storms developing after about 3pm. Once this cloud clears across S Vic later on today we should have a nice view of any action within about 150km-200km to the E and NE. (Some good vantage points are the E facing carpark at Mt Dandenong, Doncaster Shoppingtown Rooftop Carpark, Kangaroo Ground Fire Tower).
|24||.||Strengthening high moving
across Tasmania during Thursday, consolidating with the high currently over New Zealand.
Inland trough through NSW & Queensland broadening & edging slowly west triggering
scattered storms along its entire length. Low in the Coral Sea continuing to deepen
slowly & move SW. Moist easterly flow onto the NSW & Queensland coasts with
scattered showers likely, particularly in the north. Some seasonal storm activity over
northern Australia but moreso over the northwest of the continent where there is more
available moisture. The West Australian heat trough moving east will direct hot NE winds
over the southeast of the state & trigger scattered storms to its east, while areas
closer to the west coast should come under the influence of a cooler SE flow with some
drizzle or light showers on the south coast between Esperance & Cape Leeuwin. Winds
over South Australia should tend more NE as the high progresses towards the Tasman &
the east Australia trough continues to broaden and extend westwards & isolated storms
are possible in the NE of the state. Victoria will continue to warm with more easterly
winds prevalent over the state, with isolated storms possible over the ranges with the
increasing moisture field & rising temperatures. South of the ranges will remain
mainly fine. Tasmania will be mainly fine with the high moving across the state &
Risks: Complexities associated with declining pressure in the Coral Sea and interaction with the Queensland inland trough will see the progressive dissipation of the ridge and its replacement by a trough. Such a dynamic setup may produce the possibility of moderate to heavy falls of rain on the SE & central Queensland coasts and adjacent hinterlands. Also during the weekend, a slow moving trough entering SE Australia may trigger localised severe storm activity through eastern SA & Victoria. Watch for updates. Over the Top End of Australia there is evidence of increasing monsoonal activity with the ITCZ becoming more active over the next few days. A fairly strong surge of cooler outflow extends south from Japan towards South China. This strong pressure surge should extend to the equator in the next couple of days, filtering into the Southern Hemisphere and increasing convergence along the ITCZ. This may result in a burst of monsoonal activity over northern Australia - the long awaited 'rainy season'.
|23||David Jones||I'm sure I'm not the only one to pick up on it but the models are all developing a significant surface trough over South Australia in the coming days. At the same time, convergent moist NE flow is progged to develop on the eastern side of the trough, coupled with a good supply of mid level moisture (evident presently over South Australia) which advects east in the mid/upper level westerlies. This all coincides with a steady warming of the atmosphere, with thickness values in the mid 560s through Victoria by Friday. This looks like a classic thundery situation for eastern (and possible central) parts of Victoria, and not surprisingly, every precipitation prog I have seen is developing convective rainfall over eastern Victoria (Thursday) and extending throughout central and eastern parts of the state on Friday and Saturday. This is reflected (somewhat in the official forecast) http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDV10310.txt which suggests showers and thunderstorms (part. for the eastern ranges) over the next few days. This is all well worth watching...|
|23||.||High ridging through Bass Strait. Extensive trough through the eastern states will trigger storms along its length as it moves east into moister air, particularly in N & E NSW & Queensland. Ridge along the Queensland coast directing SE winds onto the coast continues to weaken while an area of low pressure moves WSW through the Coral Sea into our region. Seasonal storm activity again remaining more active in the western parts of northern Australia for the next day or so - the monsoon trough continues to edge southwards. Western Australia comes under the influence of hot northeasterlies with the west coast trough broadening to include much of the state with isolated storms in the eastern parts of the southern half as well as the north. Western coastal areas are likely to be under the influence of moist northwesterlies which will help keep temperatures moderate, however, inland areas, particularly in the east will be warm to hot. Northern parts of South Australia will warm under the influence of E/NE winds, while coastal areas will remain under the influence of onshore SE winds with the high in the Bight. Victoria clearing through Wednesday with mild SE flow keeping temperatures mild in the south, while north of the ranges warms up. Showers & possible storms on the northeastern ranges during the afternoon in the extreme southern portion of the lingering trough. Front crossing Tasmania will trigger scattered stream showers in the SW flow.|
|22||Harald Richter||VIC actually has a
shot at some lightning. Surface obs as of 22/02 UTC show a
(cyclonic) surface circulation over E VIC associated with some
enhanced moisture advection into Gippsland. Several thunderstorms have initiated in the mass/mess of cloud (Mt Buller (VIC); E of Urana
(NSW); ENE of Holbrook (NSW)(!!) and E of Tumut (NSW)). In NW
flow the N side of the ranges has the advantage of orographic
The 23Z SWG sounding showed some CAPE and a decent unidirectional shear profile. The 23Z MML sounding showed deep moderate moisture and no significant shear, but was slightly colder (-14 C instead of -12 C) at 500 hPa. SSY had some good CAPE, but is in danger of some drying in NW flow as time goes on, but don't rule it out yet. I'll be monitoring the quadrangle Wagga-Sale-Mallacoota-Wollongong-Wagga for more developments.
|22||Clyve Herbert||It was interesting to follow the movement of a region of vorticity mainly between 500hpa and 300hpa over the last three days as this area moved from near to southwest WA to be located just north of Melbourne at 0900hrs this morning, this vorticity area had a marked influence of weather across a large area of SA and south east Australia, however I was a somewhat surprised at the very little interest (at a public level ) shown by the BOM in its movement and the subsequent weather conditions that were generated. The trough through NSW is looking good for storms today.|
|22||.||High ridging south of Tasmania cradling
the quasi-stationary trough over eastern Australia which traces NW to the tropics.
Northerly winds in NSW increasing temperatures with widespread middle-level storm activity
(embedded), both inland and along the northern coast. Quidge* being maintained along
the Queensland coast by the strengthening high in the Tasman keeping storms towards the
central and western parts of the state nearer to the trough. Seasonal storm
activity in the tropics becoming more active as the monsoon trough slowly edges southwards
with widespread storm activity expected over the northern part of the Northern Territory
north of Tennant Creek as well as in the Kimberley and much of the Pilbara.
Conditions in southern WA warming again under the influence of the deepening heat trough
& the high in the Bight ridging along the southern coast. South Australia
(except for the far north where isolated storms can be expected in the trough), Victoria
& Tasmania will remain under the influence of SE onshore winds, although the eastwards
movement of the mid-upper level vorticity centre (500 to 300hPa) across northern Victoria
may be slowed by the presence of the ridge south of Tasmania. In this case,
generally cool and unsettled weather will continue across the southeast of the continent
for the next day or so.
Convective area near Fiji is developing strong outflow aloft in response to the strengthening jet to its SE.
Quidge* = Queensland ridge
|21||.||Extensive cloudband over central & SE Australia has its focus near to a broad vorticity area between 500 & 300hPa near to the Adelaide region. The presence of this vorticity area appears to have aided in the intensification of the mid & upper level trough which extends northwest to the Kimberley. This infeed of moisture can be traced back to west of Indonesia where there is a marked positive convective area. There is a risk that this vorticity region may become cutoff by the high in the Bight & with a moderate strength ridge off the east coast may result in a quasi-stationary situation over southeast Australia. This may lead to more general local to moderately heavy falls possible, although the situation seems rather marginal at the moment.|
|21||.||Broad trough covering much of inland eastern Australia during Monday cradled by the ridge of high pressure up the NSW & Queensland coasts and the baric ridge to the south through the Bass Strait / Tasmania area. Onshore winds on the east coast will keep temperatures moderate through the early part of the week while away from the coast temperatures will be rather higher with the generally NW flow. Widespread showers & scattered thunderstorms throughout much of eastern Australia as well as in the northwest of WA in the moisture field feeding in from the Indian Ocean from the south of Indonesia. Occasional storms over the NE Top End & Cape York, but generally settled weather over the remainder of the tropics in Queensland & Northern Territory. Heat trough in WA along the west coast with NE winds through the central & west of the state & SE winds on the southern coast as the high ridges across the Bight. SA will spend most of the next day or two under the large band of middle level cloud with a generally SE flow across Tasmania & through southern SA. Scattered storms are likely in the NE of the state. Victoria should see a cloudy day on Monday with showers & isolated moderate falls gradually shifting east.|
|20||Clyve Herbert||Looks like the trough moving through SE Aus is slowing down, should bring some interesting weather at last to Victoria although looks like a lot of mid level activity will suppress surface convection today, never mind I will take anything - even embedded mid level storms especially tonight.|
|20||.||Broad ridge of high pressure along the
NSW & Queensland coasts tilting westwards closer to the tropics will maintain onshore
winds & coastal showers. Very warm to hot in inland NSW with scattered thunderstorms
west of the ranges & in western Queensland. Trough moving through NSW during Saturday
will continue moving to NE on Sunday through NE NSW & SE Queensland triggering storms
there. With a weakening monsoon trough there will be isolated storms through the tropics,
mainly along Cape York Peninsula & NE Arnhem Land. Mild along the southern WA coast
under the influence of a ridge along the coast, with warmer conditions inland to the east
as the heat trough deepens along the west coast. Trough in NE SA is being absorbed into
the trough approaching from the west. Mostly cloudy conditions through SA on Sunday
with cloud increasing through Victoria from the west during the day. Wind change
expected in Victorian central districts during late afternoon and early evening allowing
temperatures to reach the mid-high 30's in the strengthening NW before cooler SW winds
extend through. Showers and isolated storms are expected ahead of the windchange with
scattered storms on the NE ranges again. A warm and cloudy morning in Tasmania will be
followed by showers - particularly in the NW, through the rest of the day.
Watch these: Possible middle level low forming over southern WA / northern Bight moving across Victoria during Monday.
|19||.||High moving away into the Tasman Sea extends a broad ridge of high pressure up the NSW & Queensland coasts. Both states will be mainly under the influence of warm NE winds & remain mostly fine except near to the trough which extends from the Tennant Creek area to the NE of Victoria and is continuing to edge slowly west. Expect isolated storms in the vicinity of the trough along its entire length. Onshore winds in coastal Qld will keep conditions mild. Seasonal storms near the Gulf coast & in the Barkly Tableland. Monsoon trough contracts more westwards with scattered storms mainly in the Kimberley and adjacent areas. Cooler onshore winds in the southern parts of WA after the passage of a weak front. High moving into the western Bight ridging SE. South Australia & Victoria are experiencing increasing temperatures with the high maintaining a NE flow across the southeast parts of the country. Surface trough running through NE SA will become absorbed by the area of lower pressure in South Australia. Isolated thunderstorms can be expected in the far west & NE of that state. Upper ridge over Victoria & Tasmania during Saturday will stabilise conditions except over the NE ranges, which is under the influence of the trough & may experience isolated thunderstorms during the afternoon.|
|18||.||High in Bass Strait ridging up the NSW
coast & along the Queensland coast - yep...a quidge!! Broad surface trough
extending from western Queensland through western NSW and towards the SE of the continent,
slowly tilting to the west towards its northern end. Thunderstorms in this area,
particularly in central and northern Queensland, particularly around the Gulf region. NE
winds along the Queensland and northern NSW coast - dry & very warm away from the
coast and cooler in the far southeast of NSW. Monsoon activity along the very northern
coast of Australia joining up with the heat trough in WA. Scattered storms can be
expected through the NT & into northern WA.
The WA trough is deepening & extending further south & beginning to move southeastward with some of its cloud shearing off towards the NE with the upper jet. The upper support for this system is beginning to weaken, but there is currently a large area of upper level 'troughiness' in the Indian Ocean to the west of WA. (ie: the flow is highly meridional at 300hPa). The front approaching SW WA is expected to weaken & slide away to the SE with winds from the SW onto the southern WA coast as the trough moves towards SA. Temperatures in SA & Victoria will increase with NE winds over the next 24-48 hours, with an increase in moisture availability but generally remaining fine except in the far western parts of SA. Tasmania will be mainly fine.
Watch these: The area south of India & east of Madagascar (10S 75E 1600AEDST Thursday) for the possible development of a tropical low.
|17||Clyve Herbert||Have you noticed that most of the cloud developments of the Australasian tropics have all but disappeared over the last two days, just as if the area has sucked in a huge breath...but will soon exhale!. Also the southeast of QLD looks ok today for some storm activity|
|17||David Jones||Every day that goes by, the models look less and less
hopeful. I really can't see any storms happening on Saturday
despite the presence of a general trough across Victoria and
reasonable instability indices, as (in particular) the
atmosphere mid and low levels look too dry. Sunday looks very
slightly more hopeful, though again there looks to be insufficient moisture. In addition I notice the models are developing an increasingly
anticyclonic frontal passage (read lesser trigger), and push this
through earlier in the day. In fact, based on some of the
models it could arrive during the morning. Based on this kind
of scenario, I would expect any storms to be (largely)
limited to the eastern ranges (hope I'm wrong!). My
suspicions are that if we are going to see any real action it won't be till next week when the high following closely behind Sundays expected
change migrates to a position well south of Victoria. IF all goes to
plan, a secondary trough COULD develop over south Australia
by late Monday in association with a middle level trough
progged by most models.
My tip for temperatures is that we will only see one hot day in Melbourne out of this. This will be Saturday if the front is running a little ahead of time, or Sunday if the front is on the slower side of the model scenarios.
|17||.||High in the Bight extending a weakening ridge up the NSW coast with broad trough remaining over much of NSW. Mid-level disturbance moving NE across NSW & southern Queensland. Storms in northern NSW & SE Queensland as well as along the Queensland tropical coast especially as trough moves northeast. Dry & hot behind the trough. Generally low pressure across the north of the country with easterly flow becoming re-established. Heat trough in WA moving westwards to lie just in from the coast during Thursday directing hot E-NE winds across the SW of that state with the high maintaining a ridge along the southern coast. Upper level disturbance over the same location near the coast. Scattered storms expected in the SW, some severe. Seasonal storms also in the Kimberley and the Pilbara, particularly in the east. Mainly SE winds across South Australia & Victoria with an upper ridge stabilising conditions through Thursday. Weak front expected through Tasmania & Bass Strait during the early part of the day reinforcing the SE airflow, particularly in the south of Victoria. Warmer with NE winds north of the ranges.|
|16||Clyve Herbert||There seems to be little interest in the upper low west of Mildura, it looks a little lonely so I thought I would give it a mention, seems to be drifting east northeast along the tail of stronger upper westerlies (above 300hpa) may trigger a few storms over south-western NSW today. It will be interesting to see if it maintains its identity over the next two days, if so this upper system may interact with higher moisture levels further east along the central NSW coast.|
|16||.||High in the Bight ridging strongly SE with a weakening ridge up the NSW coast into southern Queensland. Trough along the west of the ranges through NSW & into Victoria's northeast again, possibly extending its influence westward during Wednesday. Storms likely, particularly along western side of the ranges in NSW. Monsoon trough contracting NE towards 10S, leaving much of Queensland under the influence of SE winds sustaining moisture levels but remaining mainly fine except in the tropics. WA heat trough moving westwards towards the coast, maintaining generally easterly winds through the central & southern parts of the state & combining with upper disturbance moving across the south from the Indian Ocean & triggering scattered storms in the SW. Isolated tropical storms in the north of the state & the eastern Pilbara region. South Australia should see increasing temperatures & NE winds particularly in the north triggering only isolated storms away from the coast & more particularly in the west closer to the trough. Winds in Victoria swinging around to the NE increasing both the temperature & humidity levels. Isolated storms on the northeast ranges are possible. Mild along the coast and warm inland. Tasmania will remain mild under the influence of S-SE winds thanks to the high.|
|15||Nick Sykes||Well with the last well below average day
just about past us it is time for the Vics to look forward to some more seasonable
weather. Depending on which model you look at we could be in for some very interesting
weather. The most likely scenario and the one favoured by EC and NGP at this stage is for
a gradual warming trend as the high pressure system in the Tasman slowly becomes dominant.
This will see a period of fine and settled weather up till the weekend with temps going
pass 30 on Saturday. A trough is expected to to move across the state on Sunday and
generate some storms. During this period a weak, fairly inactive trough will be over the
Now onto GASP. For the last day or so GASP has been going for a very interesting scenario over Vic from the weekend. It has the trough deepening over Vic on Sunday with it now remaining basically over or to the west of Vic until Wednesday next week!!
This deep trough is forecast to drag some very warm air in from the north. Thicknesses over Vic are expected to be 776+ by Monday next week and remaining that way through until Wednesday when they are progged to be 580.2 over NW Vic. 850 temps are expected to rise above 20 in Melb from Monday, be about 25 on Tues and I would expect 27 judging by the thicknesses on Wednesday. This is big heat stuff, 40C temps if those values come off. With the trough triggering instability (50+ TT's) it may well be my dream period of 40C temps with storms.
|15||.||High moving only slowly through the Bight towards Tasmania, ridging towards the SE. Trough deepening down the west of the NSW ranges into NE Victoria. Isolated thunderstorms in eastern parts of the state as the day progresses. Ridge up the NSW coast and into southern Queensland (not quite a Quidge) currently sustaining onshore winds is being maintained by the low near NZ which will weaken and move off the coast into Wednesday. Showers & thunderstorms can be expected in the SE of Queensland through Tuesday afternoon especially. Area of decreasing pressure in the Coral Sea should be watched. System is currently tilting positive longitudinally, and is beginning to develop a weak tropical signature as of mid-Monday. Monsoon trough weakening in the west & slowly edging northwards towards 10S from its location for the past week or so over much of Australia's north. Heat trough in WA moving slowly eastwards maintaining a hot E-NE flow over the southern land areas in that state. Increasing infeed of moisture associated with an upper level trough in the near Indian Ocean will continue to feed thunderstorms, some severe, in the SW parts of the state. South Australia should see increasing temperatures through Tuesday as the WA trough extends its influence eastwards with hot NE-N flow becoming dominant mainly in the north of the state. Isolated storms likely in the NE. Tasmania should expect passing showers to decrease through Tuesday after early drizzle. Weak surface ridge moving through Victoria on Tuesday will help maintain a cool SE flow onto the coast with winds generally swinging around to the NE over the next day or so, bringing in more moisture from the Tasman & interacting with the deepening trough in the NE of the state. Weak upper trough passing through Tuesday leading to cooling at higher levels.|
|14||.||Cool S-SW flow being directed over the southeast of Australia by the high ridging through the Bight, which extends a ridge up the NSW coast. Upper ridge also moving through Victoria Monday. Low in the Tasman Sea continues to move slowly away. Cooler conditions should be widespread through NSW during Monday with a SE - NE flow preceding the high. Queensland coastal areas should also be influenced by onshore winds with tropical storms along the northern Queensland coast. A weak mid-level disturbance looks to form over south-central Queensland and should move eastwards into the Coral Sea over the next 48 hours. Patchy light rain is likely in southern Queensland as the trough cloudmass streams to the east in response to the strengthening jet. Continued and widespread seasonal storm activity throughout the north, weakening slightly over the Kimberley Monday. WA heat trough will deepen southwards from the western Pilbara towards the SW coast & combined with the increasing moisture feeding in from the Indian Ocean, will trigger shower activity with scattered storms. This pattern will continue as the system moves slowly east through SA & into Victoria mid-week. Scattered showers with mild conditions in the south of Victoria on Monday, fine & warmer north of the ranges. Tasmania should have scattered showers in the west with early drizzle in most areas. Clearing slowly.|
|13||Nick Sykes||The models are finally showing some
decent high pressure systems over the SE and Tasman Sea!!! From mid week we can at least
see some warm weather, and warm weather lasting more than a day. Early indications are
that on the weekend a high will be in the Tasman with a heat low/trough forming over
inland eastern Australia. This may result in quite a nasty heatwave for SE Australia (not
so much the eastern seaboard in the early stages).
O.K now for my worries. The low in the Tasman and the one over NZ may join forces and produce a nasty blocking pattern and prevent the movement of the highs east, keeping Vic in SE winds for most of the week. The models have the Lows moving east of NZ by Tuesday/weds.
|13||.||Ridge building through the Bight & ridging SE over the next couple of days, helping to maintain a cool SW - SE flow onto the southern & far southeastern mainland coast & Tasmania. Trough moving NE through Queensland having cleared through NSW & stabilised the conditions there. Trough forming along the western side of the ranges in NSW & deepening through Monday & Tuesday. Widespread trough across northern Australia leading to widespread seasonal storm activity throughout. Deepening heat trough & increasing moisture in the west & south of WA leading to scattered storm activity & generally high temperatures through most of the state.Temperatures increasing in SA especially inland as the ridge builds further eastward. Weak trough that formed over WA will trigger isolated storms as it progresses east through SA during Tuesday. Cool & showery conditions to continue in southern & coastal parts of Victoria through Sunday and into Monday. Milder and fine in the north.|
|12||.||Front & associated trough moving up the NSW coast during Saturday triggering isolated thunderstorms as the moisture field improves in coastal areas and on the range , and may extend its influence into southern Queensland during the latter part of the weekend bringing some relief from the very hot NW flow. This trough links up with the monsoon trough over northern Australia & will result in thunderstorms over much of the northern & northeastern parts of Australia during the weekend. Heat trough in WA will keep temperatures very hot in the Pilbara while remaining milder to the W and SW. Seasonal storms to continue in the north. Weak upper trough has developed over southern WA but at this stage is not expected to become active during the next 24 hours. Northern SA is expected to come under the influence of the southernmost part of the monsoon trough with hot conditions & isolated storms. Slow moving high in the Bight bringing a strong SE / SW flow onto the Victorian and SA coasts with coastal showers, cool in the south & mild in the north. S/SW flow over Tasmania behind the trough will keep temperatures mild with scattered showers, mainly in the W and clearing during Saturday. Extratropical low passing to the north of New Zealand looks to deepen during Saturday.|
|11||Harald Richter||I am analysing the
0000 UTC pressure trough (= thermal ridge) along Melbourne's longitude.
A reasonable sharp SW change in the 0030 VIC AWS data occurs along
the line Ballarat - Swan Hill and should arrive in Melbourne shortly. The surface winds are turning from N to SW across this ``discontinuity.''
The 2332 UTC GMS-5 VIS image shows an initial area of cloud W of
Melbourne, with the main convection/stratus following in a
broad band that extends S from SW VIC. The cloud band tapers
off as you go N into WC VIC. Ahead of the change there's a
strong meridional dew point gradient pointing S, i.e. the
coastal areas have the best surface moisture.
The 2300 UTC MML sounding shows an average moisture of 3 g/kg below the mid-level cloud deck at and above ~550 hPa (5.2 km AGL). The lapse rates between 850 and 500 hPa are nearly dry adiabatic, so the dry convection might well be quite vigorous. The 23 Z sounding also shows that some cooling of the mid- and upper layers has taken place since 1100 UTC last night.
One of my questions is whether the post-frontal low-level moisture insertion near the surface will be able to overcome the inversion that will separate the cool moist SW low-level flow from the overlying warm dry NW flow. The 11:47 EDT lightning tracker shows basically no activity in those areas where the change has already gone through, so I'd put my money on (another) mainly non-eventful change. Evaporating precip from high mid-level cloud deck will slowly moisten and cool the sounding from above, while the SW push is going to cool and moisten it from below.
|11||Andrew McDonald||You are definitely right about the dry air with surface DP's hovering between 5C and 0C (with some even dipping into the negatives). I have a few areas in mind for today (although I won't be chasing). One is the eastern ranges (no further N than a line from Eildon to Falls Creek to Gelantipy) and another is the SE coastal area from Wonthaggi to Wilson's Prom. Given the steering flow, any showers or storms that develop over the ranges to the east should drift down to the coastal plains from Sale to Mallacoota. This system should be able to pick up some moisture from Bass Strait as it comes through and there are currently some nice showers (possible storms) near King Island at the moment so the potential is there. I fear the North East and North Central plains will be a tad too dry today and the air aloft will be too warm for anything to develop.|
|11||David Jones||I notice that the
latest batch of models are suggesting increasing moisture
levels in the trough over WA over the next few days. This
could be well worth watching for the middle to latter part of
next week, as the key ingredient missing from the past couple of
systems impacting southern Australia in recent times has been moisture, and anybody living in the SE (besides Tasmania) knows how welcome rain
would be. Presently, only GASP is going for a major rain
event, while the ECMWF model shows a middle level trough
amplifying through WA during around the middle of next week,
which COULD foreshadow significant cyclogenesis by weeks
end... fingers crossed.
BTW.. as for the current system, curiously the models are now suggesting the possibility of some light to moderate falls (1-20mm) in south central and southeast parts of Victoria over the weekend in moist unstable S to SW flow.
|11||.||Trough & front preceded by hot NW
winds moving through SE Australia during Friday moderating temperatures and triggering
scattered shower activity in southern Victoria and Tasmania. Chance of isolated storms on
the Tasmanian high country, particularly in the west & the NE ranges of Victoria.
Front should be located about the central coast of NSW by evening, accompanied by isolated
thunderstorms. Conditions hot & dry preceding the front except under the
influence of coastal seabreezes, with winds generally shifting W-SW following &
temperatures moderating somewhat. The ridge along the northern NSW & Queensland
coast will weaken with the approach of the trough with conditions in Queensland away from
the coast also under the influence of hot NW winds. The monsoon trough over northern
Australia remaining widespread with seasonal storm activity extending further west &
possibly into the northern Pilbara. WA heat trough reforming & directing hot
E-NE winds through much of the state with a ridge building along the southern coast.
A weak mid-upper level trough looks to form over southern WA during Friday or
Saturday. Conditions in most of South Australia will be moderate in a SE-SW windflow
over the next day or so as the high moves through the Bight during Friday & Saturday
with the exception of the NE which may still come under the influence of the trough with
warmer temperatures & isolated thunderstorms. The weekend in Victoria is expected to
remain cool to mild with SE winds under the influence of the approaching high with
possible scattered showers south of the ranges. Stormchasers should head to the
Queensland tropics for the weekend!
Watch this: The 2 areas of tropical interest east of the Philippines & NW of Fiji are still worth watching. Updates here
|10||Clyve Herbert||Although there is not much interest in the trough and cold front over Victoria for Friday, I wouldn't completely write it off. There is some rather dry air associated with this system and a fair bit of warming between 850hpa and 500hpa ahead of the surface trough, as this system moves east across Victoria it should get into progressively moister air thanks to a bit of a ridge off the east coast and a northeasterly drift. With a bit of heating this might be enough to kick start some thunderstorms (a bit of a wish forecast!!) mainly over eastern Victoria, although even the central district may be a possibility, keep an occasional eye on this trough especially east of a line from Echuca to Sale.|
|10||.||Ridge over Victoria slow moving to be
followed by a trough through SA. Generally southerly flow over Tasmania with temperatures
remaining mild while the rest of the SE of Australia heats up. Ridge along the NSW
coast is keeping winds light but starting to shift NE, which will increase the humidity.
Temperatures remain high in the north, while a little milder in the south. The
SW of Queensland will be dry and hot while the northeast & tropics will remain under
the influence of the monsoon & the last of Bernie. A seabreeze may drive
convection westwards from the northern Queensland coast during the afternoon. Seasonal
storm activity can once again be expected throughout the northern half of the country with
widespread storms from the Coral Sea to the Derby area. Remaining dry through the
Pilbara & central parts of WA. Cooler air is moving through the south of WA in the
wake of the front with scattered showers. SA will heat up as the trough approaches
and N-NW winds strengthen, but will become milder with the passage of the front through
Thursday especially in the south. Victoria tomorrow will remain dry & warm to
very warm especially in the north of the state, with freshening NE-NW winds ahead of the
front due on Friday.
Watch this: the area north of Papua-New Guinea has continued to become more interesting. Updates here. The area NW of Fiji has also started showing potential.
|9||.||Low in the Tasman starting to weaken
& being followed by a weakening ridge of high pressure being hurried along by a trough
& front passing through Western Australia during Wednesday. The northern
half of the continent will remain under a band of lower pressure with seasonal storm
activity extending from Timor to Brisbane & generally to the north of this line with
some isolated storms also in the Pilbara. The area of storms, that Tuesday night
were south of Timor, originated on the Queensland / NT border on Monday & moved
'upstream' in a NW direction assisted by a mid-level SE flow - rather an unusual direction
of movement. The area of cloud in the Coral Sea has moved southwest & been absorbed in
the outflow from Bernie. NSW will remain warm to hot & dry except along the
coastal fringe where SE - NE will help to moderate the temperature while increasing the
humidity. The low S of Western Australia is expected to deepen for the next day or so, but
then weaken as it moves towards Tasmania & leave only a small cold air field to affect
southeastern Australia later in the week following the passage of the front. The
front passing through WA will trigger showers in the south. The weak ridge currently over
western SA precedes the trough & the subsequent mixing of air down to the surface from
the middle levels will substantially warm SA, Victoria & to a lesser degree, Tasmania
before the arrival of the front late in the week. The prefrontal trough will deepen
as the system moves east & the east-west temperature gradient steepens, bringing
eastern parts of SA & Victoria under a hot, dry NW flow later Thursday & Friday.
Watch this: the area north of Papua-New Guinea (7.5N) has become more organised & is now being watched by JTWC.
|8||Courtesy Robert Goler||Infrared imagery of TC Bernie from earlier this month in the Gulf of Carpentaria|
|8||.||The low, having moved SE of Tasmania over
the past 24 hours will continue to direct a cool southwesterly flow over South Australia,
Tasmania and Victoria with showers in the cooler air towards the south as air from the
Southern Ocean is also captured by this low. A weak ridge moves into SE Australia
during Wednesday. The strengthening 300hPa jet has dragged much of the cloud associated
with Bernie and the southern Tasman low off north of New Zealand but occasional storms
will again be triggered in NE NSW and SE Queensland as the trough continues to move along
the coast & interacts with the last vestiges of Bernie. Seasonal storm activity
through northern Queensland, NT & the northern parts of WA with possible isolated
storm activity over the west Pilbara with the increasing moisture in the area.
Showers becoming more frequent along the south coast of WA following the passage of the
front, while the heat trough will move east as the front moves east maintaining high
Watch these: the convective area to the northeast of Papua-New Guinea for improving organisation. A deep cold pool to the SW of WA may affect the southern parts of Australia later in the week.
|7||.||The front that moved through Victoria & Tasmania overnight Sunday & early Monday has left both states in a rather cooler SW airstream with showers in Tasmania, the south of Victoria with possible thunder while remaining mainly fine north of the ranges.The low has moved southeast overnight bringing S-SW winds across Tasmania and is expected to begin to move eastwards while cradled by a ridge of higher pressure to the south. The trough currently moving NE through NSW and extending its influence into southern Queensland will trigger storms mainly north of Sydney along the coast and to the west of the ranges on Monday with a cooler SW airstream to follow - it is currently interacting with the outflow from Bernie & may produce some heavy falls. Also, the interaction between the remains of Bernie and the monsoon trough will continue to be responsible for widespread storm activity in Queensland. Note the infeed from the tropics north of the Coral Sea onto the northern Queensland coast which may see heavy rain in that area on Monday. The low in the Coral Sea continues to move SW & should be watched for the next couple of days. The cloud over the Indian Ocean which originated as part of the low that developed at ~25S is becoming drawn into the low currently well south of WA by the subtropical jet.. The high in the eastern Bight will weaken as it moves eastwards but is followed by a stronger high currently to the west of WA. Showers will clear from the eastern parts of the south of the state, while a developing heat trough towards the western coast will increase temperatures again. Seasonal storm activity is expected to continue in the north. South Australia and Victoria tomorrow should be cooler with passing showers in the southern districts & strong winds especially in the south of the state decreasing from the west as the high moves through the Bight.|
|6||Nick Sykes||Victoria is looking half interesting
today, well maybe tonight. Today will be hot, there is some cloud over the state but this
is mainly high and once the inversion breaks and the northerly mixes out this should be
blown south. Temps are expected to get into the high 30's, we will see.
Things get interesting later today/overnight. As the front moves across Vic it isn't expected to do much, maybe the odd thundery with the front. It's into the night that things look up. It looks as if the northerly flow ahead of the front will hook up with some of TC Bernie's left over moisture and rapidly inject it south into NE Vic and NSW.
LI's are progged to be in the -4 to -6 range, a lovely moisture tongue feeding into the frontal line, a dry slot behind, and dry @ 500mb!!!
|6||.||The low in the Bight will remain slow
moving as the ridge which passed through Victoria on Saturday moves into the Tasman. The
outflow from ex TC Bernie continues to move southeast through Queensland and
central-northern NSW & is being taken rapidly eastward by a strengthening 300hPa jet.
Bernie has retained a tropical signature even while over land. Rain periods in
northern NSW & the majority of Queensland are expected with embedded storms. The
monsoon trough is stronger from Bernie's location to the Coral Sea than over Western
Australia, but scattered storms are to be expected in the north of Western Australia while
the southern part of the state is affected by the passage of the low to the south &
the high coming in behind it, directing cool SW winds onto the southern coast. The trough
will move through SA during early Sunday shifting the winds around more to the SW &
dropping temperatures. The passage of the trough may trigger isolated thunderstorms while
the influence of moisture from Bernie may result in rain areas in the NE of the state. As
the trough moves through Victoria, rising temperatures & strengthening winds will see
a rapid drying of the state ahead of the westerly change which will trigger local storms
with its passage & swing the winds around to the SW.
Watch these: the large area of cloud over the Indian Ocean approaching WA is bringing moisture down from the tropics & is associated with a developing low at ~25S as well as responding to the strengthening subtropical jet over the area. The area of low pressure to the east of Honiara is starting to show signs of development.
|5||Courtesy Michael Bath (NSW)||Links to imagery of the waterspout that
fouled the Sydney - Hobart last month
|5||.||Ex-TC Bernie looks to continue moving SSW
& will become absorbed into the general troughing across the northern part of
Australia which extends from Western Australia, through Queensland and into northeastern
NSW. Moisture from the Coral Sea is combining with the upper outflow of Bernie &
will assist in the development of storms over the Queensland central and coastal regions
as the trough continues to move eastward. A significant increase in moisture levels
over northern NSW & southern Queensland has encroached further south through to
the central coast of NSW as a weak mid-upper level trough over northern South Australia
maintains its current alignment (NW-SE) & these areas will see storm activity through
Saturday while the rest of NSW remains dry with cooler conditions to the south.
The first significant 300hPa trough for some time is currently to the S of WA, with an associated cold air field in the middle levels as well as at the surface moving up from the Southern Ocean. Southern parts of WA can expect cooler showery conditions with a continuation of seasonal storm activity through the north of the state particularly in the Kimberley. Warm air through the mid-levels with this system will advect ESE & may trigger isolated shower & storm activity in South Australia today but with more widespread activity expected through Victoria during Sunday. Mixing from the warming mid layers down to the surface will see temperatures in SA & Victoria rising with the approach of this trough.Tasmania will see an increase in showers mainly in the west with isolated storms particularly in the northwest & central high country.
Watch these: The area of convection north of New Caledonia should continue to be watched. This system has remained stationary for days due to a lack of upper steering flow but is expected to move WSW over the next few days into the Coral Sea.
|4||.||TC Bernie has remained quasi stationary in the Gulf of Carpentaria since yesterday but is showing strengthening upper divergence particularly in the southeast quadrant while moving slowly SSW. Outflow moisture from this TC can be seen over most of Queensland and parts of South Australia. Another low is currently south of Tasmania & is being followed by another to the south of Western Australia. Isolated showers & storms should remain in the northern parts of WA and in the south, the passage of the front will trigger an increase in activity in the southern part of the state later today. A mid-upper level cold pool is becoming apparent over central South Australia marking the position of the 300hPa trough. The front approaching SE Australia is expected to only trigger passing showers in the southern part of Victoria but more-so in Tasmania. A weak ridge of high pressure extends across SA & NSW. The entire south east of the continent will start to warm over the next couple of days. The trough running from the Gulf towards the southeast of Queensland will trigger storm activity during today, more particularly on the west of the ranges, extending into NE NSW.|
|4||Clyve Herbert||The synoptic set-up over southern Australia is on the change and is showing meridional tendencies, it seems at last that the long spell of mid lat westerlies is on the wane.|
|3||.||Low SE of Tasmania weakening and moving
away towards New Zealand. A further low moving across the southern end of the Bight
and a low at 40S south of WA has developed. The monsoon trough activity is increasing
currently across the north of Australia. Low in Gulf showing signs of better organisation
with improving upper level outflow, but is currently moving towards the land
surface. Showers & thunderstorms associated with this low should influence
the majority of tropical Queensland and Northern Territory over the next couple of days.
Dry & hot in the southern & eastern areas of Queensland. More showery weather for
Victoria in a moderating W-SW flow, cool in the south & fine in the north of the
state. Remaining cool with isolated showers in South Australia's southern regions.
More showers for Tasmania in a SW flow. Cooler SW flow becoming established across NSW
through the day, dropping temperatures but not helping the low humidifies that have been
experienced over the last week or two. Decrease in storm activity in southern areas
of WA. The heat trough will move off the coast directing a warmer easterly flow to
southern parts of the state.
Watch these: area of tropical activity currently south of Sri Lanka feeds moisture into a low developing west of WA. The area of convection north of New Caledonia should be watched for improving outflow.
Two areas of interest for TC watchers, the Gulf area is still showing positive development although inflow convergence is variable with occasional weakening and redevelopment, the surface low is difficult to pin down but seems to have moved or redeveloped over the central Gulf area which may favour better organization today. What seems to be a better prospect is a rather strong looking development centred near 10south 165east near to Honiara and only moving slowly, this development is at the far north-western end of a trough extending from southeast of NZ. This system is showing signs of vacuum cleaning the area around its circumference. The former TC well east of NZ has fully transformed into an extra tropical low.
PS. At the other end of the scale the cold air region over Tasmania and Victoria will become increasingly more unstable today with the risk of the odd strong cold air storm, even the possibility of wet snow above 1500m.
|2||.||The low south of Tasmania
is continuing to move east & exert its influence over Tasmania & Victoria.
Slow moving trough in NE NSW. Tropical areas of Qld, NT & WA continuing to come
under the influence of the monsoon. Upper trough developing west of the SW land area of WA
will destabilise areas including the northern Goldfields & the Gascoyne with activity
being rather more to the north of these areas today as the ridge along the southern coast
brings onshore winds. Continuation of seasonal storm activity in the north.
South Australia will remain under the influence of cool, moist onshore winds in southern
areas bringing scattered to occasional showers, with conditions warming in the north.
Victoria should see a continuation of yesterday's showery weather in the south with the
possibility of hail & thunder in the cool air field. Temperatures in the south will
remain low for this time of year as the low moves away, directing a more southwesterly
flow over the southern part of the state. Fine in the north. Tasmania remains under the
influence of the low to the south & is likely to see showers tending to rain with
occasional thunder. NSW will remain mainly dry & warm to very warm before a cooler
southwesterly surge moves through the southeast of the state later today. The
eastern & northern parts of Queensland come under the influence of the moisture infeed
from the tropics, and showers & storms will be likely through the whole region
today. Southern Queensland will tend dry & hot, although with the moisture
infeed to the area improving later today, isolated storms may occur.
Risks: the small isolated cloud patch currently over the central NSW coast & located within the trough area should be watched for further development during today. Although the circulation in the Gulf of Carpentaria is disorganised at present, the system is showing signs of cyclonic 'turning' & should be watched.
|1||.||Fronts embedded in the westerly airstream will affect Victoria and Tasmania over the next couple of days. The trough moving through NSW should trigger storms on the Northern Tablelands, Northern Rivers and southeastern Queensland. Tropical storm activity through the Northern Territory north of Tennant Creek and tropical Queensland will continue as a broad trough remains over central Australia directing a moist westerly flow over the region. The high ridging through the Bight looks to weaken. Western Australia can expect storms to develop under the influence of the deepening surface trough combined with an upper level low to the west of the SW land region. Seasonal activity looks set to continue through the Kimberley & adjacent areas. South Australia can expect showers with possible thunder in the westerly airstream with the mid levels continuing to cool. The deep low south of Tasmania is moving only slowly east & will continue to affect Tasmania bringing stream showers, particularly heavy to the west coast with the chance of thunder. Southern NSW will remain under the influence of the fronts passing through Victoria & may see occasional light showers with cooler temperatures than the rest of the state.|
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