September 2002 Forecast Outlook, Discussion & Report Page Victoria |
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| Date | Name | Information |
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| 30 | David Jones | I think the front for the middle of the week (Wednesday) certainly bears watching. While this might not look so impressive, there is a tongue of significant moisture off the western Australian coast at present, extending from near Indonesia to around Shark Bay. The approaching front has an associated upper trough which extends well into this region, and should provide for a good draw of tropical moisture towards Victoria in advance of this front. The trough also tends slow right down on Wednesday, which could see the associated cloud band take a good time to pass through. The BIG question is will it be precipitating much. Personally, I wouldn't be surprised to see a reasonable thundery rainband develop (this bears some similarities with the system of two weeks ago)... anyway one to watch. |
| 30 | . | Overview: The high has
remained quasi-stationary in the head of the Bight during Sunday, while the broadening
cloudband associated with the trough over Queensland and the Territory has moved
northeast. The cold pool which was responsible for the snow falls & hail during
Saturday in Victoria has moved northeast with storms over the central New South Wales
coast later Sunday. The trough down the west coast has deepened through Sunday and the
next high is ridging into our longitudes near to 35°S. Discussion: The high in the Bight will move slowly eastwards during Monday bringing cold nights to southeastern Australia with the risk of isolated severe frosts in protected inland areas. The trough will continue to move northeast while the trough down the west coast will linger near the coast before moving east during Monday. Scattered showers will continue along the northern New South Wales and southern and central Queensland coasts while the high remains over the southeast of the continent. The front approaching the southwest on Sunday night will slip to the south beneath the high and influence only the far southwest. Rainfall potential |
| 29 | . | Overview: A complex
low pressure (at the surface and upper levels) moved across Victoria today
bringing significant snowfalls over higher parts of the ranges and in the south. Sleet was
reported close to sea level. A funnel was reported from Point Hicks in the east. The
surface feature is located in the western Tasman on Saturday night. A high pressure system
has become slow moving and is located near the head of the Bight with a ridge to the
southeast. The trough across the continent from northeastern New South Wales to northwest
Western Australia remains quasi-stationary with moisture continuing to be drawn in from
the northwest. Discussion: The high in the Bight will remain slow moving through Sunday and is likely to strengthen, and affect conditions over much of southeastern Australia by later Sunday and Monday. The complex trough over Victoria will dissipate with the upper trough moving northeast. In Western Australia, the west coast trough will deepen steadily and remain located along the coast during much of Sunday. A front is approaching the southwest corner. The broad trough across the northern half of the continent is likely to trigger further showers and scattered storms, particularly in the northwest as further tropical moisture is brought in from the Indian Ocean during the next day or so. It will also remain quasi-stationary. Moisture is feeding into much of the northern part of the continent from near and east of New Guinea. Rainfall potential |
| 28 | Clyve Herbert | Looking interesting over southeast Aus tonight with rather good vorticity associated with a cold pool moving east northeast just southwest of Mt Gambier, the whole of south east Australia looks favoured for the development of a low pressure system. The cold pool has a 500hpa temp of about -30C not too bad for this time of the year. |
| 28 | . | Overview: The surface
trough over eastern Australia has edged southwards during New South Wales, while extending
across the continent from the east coast to the Kimberley region. A low pressure system
has moved through the eastern Bight to be southeast of Tasmania on Friday night with its
associated front crossing Victoria and Tasmania. An area of enhanced midlevel
vorticity associated with a cold pool in the Bight southwest of Mt Gambier, continues to
move very slowly northeast. Widespread storms along the trough during Friday, mainly
through New South Wales. The high in the west is ridging into our longitudes near to 38 -
40°S, just to the south of the continent. A narrow moisture plume extends from the area
of convection south of Sumatra and can be traced along the southwest side of the trough
through the continent. Discussion: The thermal (cold) trough will cross the southeastern part of the continent during Friday night / Saturday bringing colder conditions and snowfalls over the alpine areas. There is also a deepening upper trough over the region. There are early indications of enhanced vorticity within this area, which should be monitored as it moves (probably) northeast. The thermal trough will be replaced by the strengthening high currently moving through the western Bight, but the high will weaken as it moves across the southeast corner later in the weekend / early in the week. The heat trough over the Western Australian will begin to deepen down the west coast later Saturday and into Sunday. Areas to watch: The area of enhanced vorticity in the midlevels southwest of Mt Gambier should be watched for developing interaction with other synoptic scale features, both over southeastern Australia and to the northwest as well as the moisture plume feeding in from the area south of Sumatra. Things could get very interesting if this system develops further, especially if it moves across inland Victoria. Rainfall potential |
| 27 | Clyve Herbert | Interesting to see the amplification of a mid/upper level trough over eastern NSW this morning, its unfortunate the lower levels are a little on the dry side, but worth keeping a check on, also some respectable radar returns south east of Victor Harbour along the cold front although this cloud band appears to be a bit complex - possibly an upper cold pool mixing into the set-up. |
| 27 | Nick Sykes | Today looks a chance, with quite unstable air coming in from the west, moisture may be a problem. Tomorrow looks interesting with a very cold airmass coming through, the latest sat pic has a nice pool of cold air developing to the SW of Vic. Could be an interesting Grand Final with heavy showers and hail/thunder likely to be around during the game. |
| 27 | . | Overview: The high
continues to ridge into our longitudes along the southern coast of Western Australia and
into South Australia continuing a weak baric ridge into the Tasman Sea, with lows
and their associated 'short' fronts moving east through the Bight and affecting only the
southern coastlines. The trough extending through southeast Queensland into the
southwestern part of the Top End has triggered storms along much of its length through
Thursday. This trough is moving only slowly. Much of northern Australia
remains under the influence of a weak trough. A midlevel cold pool is located southwest of
Mt Gambier at the head of a strengthening upper trough with colder air being sourced
from the Southern Ocean. Discussion: Further fronts will cross the southeast during Friday and Saturday bringing cooler conditions and the likelihood of snowfalls over the higher parts of the alpine areas. Winds will restrengthen during Friday with the approach of the fronts. The ridge of high pressure along the Queensland coast will remain through Friday, helping to contain the trough which has become quasi-stationary through the inland. Moist infeed from the northwest will help sustain scattered storm activity through Friday. Moisture will also feed onto the northeast tropical coast from an area of convection near to the Solomon Islands which looks likely to trigger showers, some heavy, over the Cape York area during Friday. Areas to watch: a large area of strong convection has developed to the south of Sumatra. Rainfall potential |
| 26 | . | Overview: A series of
fronts has crossed southern Australia lying south of the ridge of high pressure edging in
from the west and weakening. Another low in the series is moving along the southern
Western Australian coast during Monday night. The eastern Australian trough lies through
northeastern New South Wales and into Queensland and the Northern Territory with much of
its length being identified by high cloud, with the lower layers remaining dry. The
exception to this is the northeast of New South Wales and southeast Queensland.
Isolated high based storms occurred along inland parts of the trough, with late storms
near the coast. Fronts crossing southeastern Australia also triggered scattered
storms. Discussion: The ridge building through Western Australia will remain weak during Thursday, with areas of low pressure and troughs moving south of the ridge bringing continued showery conditions with the chance of isolated storms to much of southeastern Australia again during Thursday. The ridge along the Queensland coast, maintained by the high in the Tasman Sea, will continue to slow the eastward movement of troughs moving through the region north of ~35°S, while the fronts will shear away to the east more rapidly to the south. Weak infeed from the Indian Ocean will continue to feed into the trough running through the Territory into southern Queensland and northeastern New South Wales, triggering showers and isolated storms. While the western section of the trough will remain quasi-stationary, the eastern section of this trough will continue to move northeast during Thursday, with showery conditions clearing behind it. Rainfall potential |
| 25 | . | Overview: A complex
trough lies through eastern Australia with a ridge of high pressure extending along the
east coast from the high in the Tasman Sea. A high in the Indian Ocean is ridging through
Western and South Australia along 35°S, while a satellite low and associated front
travelling around the northern side of the broad trough in the southern Bight is moving
along the southern coast of Western Australia. Another satellite low is developing to its
southwest. A trough and front crossed Victoria, southern New South Wales and Tasmania
during Tuesday with showers and scattered storms. Discussion: The complex trough will linger over the eastern Australian region while moving slowly northeast through New South Wales and into inland Queensland. The high in the Tasman Sea will maintain a ridge along the Queensland coast, directing moist onshore flow while slowing the eastward movement of the trough. Conditions over inland Queensland will continue warm to hot. The incoming ridge of high pressure over the west of the continent near to 35°S, will steer a series of lows and fronts towards South Australia and across the southeastern states during the next few days. Northern Australia will remain under the influence of generally low pressure, with a continuing buildup of midlevel moisture through the Northern Territory feeding into the trough through eastern Australia. Rainfall potential |
| 24 | . | Overview: Much of
eastern and southern Australia is influenced by either the trough which has remained
quasi-stationary during Sunday, and moved slightly east during Monday or the trough
approaching from South Australia. Storms affected areas about the ranges and near the
coast from southeast Queensland to northeast Victoria. The high drifted southeast and
weakened during Monday, while the front and prefrontal trough moving through eastern
Western Australia have virtually amalgamated with the trough lingering over eastern
Australia. the low moving through the Bight ahs a satellite low moving along its western
side and a stronger ridge of high pressure is approaching the west coast. Discussion: During Tuesday the trough lying through eastern Australia will dissipate & become absorbed by the more active trough advancing from the west. The front will produce scattered showers over the South Australian coastal area with cooler conditions. Isolated middle level storms may form in the trough as it moves east. Storms are likely along the eastern coast during Monday night, but will become less frequent as the trough weakens and moves off the coast. A front crossing the southwest corner will bring further showers, but the incoming ridge of high pressure will keep much of Western Australia fine. Rainfall potential |
| 23 | . | Overview: Pressure
gradients across the continent remain generally weak. An early season trough sheared away
from the front that passed through southeastern Australia on Saturday and has lagged
through eastern during Sunday, extending slightly southwards into northern Victoria during
the late afternoon. This trough is cradled between a weak ridge of high pressure to the
east and a weak high in the Bight. To the west of this high and its ridge to the south,
another trough extends from the Pilbara region to the southern coast of Western Australia.
A front is crossing the southwest corner late Sunday. Another front passed across
Tasmania. Discussion: The trough over eastern Australia will remain quasi-stationary during Monday, moving only slowly east, while the front crossing Western Australia will combine with the trough in the west and move into South Australia. The weak high that was located in the Bight during Sunday night between these troughs will be eroded further by the low pressures across southern Australia and may even lose its identity over our region. The ridge of high pressure will be maintained along the Queensland coast by the slow moving high to the eastof New Zealand. Rainfall potential |
| 22 | . | Overview: Pressure
gradients across the Australian region at the moment remain weak. A high in the Tasman Sea
is building a ridge along the Queensland coast with an area of high pressure over the
eastern half of New South Wales. The weak front that passed across the southeast during
Saturday has sheared away to the east and left a trough lingering through Victoria, New
South Wales and South Australia. A high is ridging through the Bight near to 35°S with a
front passing through the western Bight close to the southern West Australian coast. The
trough over the northwest of the continent is encroaching the ridge and patchy cloud
developed in the south of the trough during Saturday afternoon. A weak mid-level
disturbance has moved into New South Wales while another is located over southeast
Queensland during Saturday, but has remained largely inactive. Discussion: The trough through the eastern states will become quasi-stationary through Sunday, and will move only slowly eastwards. A high over South Australia and the Bight will remain weak and locked between troughs to its east and the west. Much of the continent will remain fine with pressure gradients remaining weak and systems moving slowly to the east. A front will cross the southwest corner during Sunday bringing showers. Rainfall potential |
| 21 | . | Overview: The high has
weakened and moved east to lie near the coast of New South Wales by late Friday. A weak
upper trough lies just off the coast of southern Queensland. General low pressure at the
surface (with an upper high overlying) affects the north of the continent with a localised
afternoon high pressure apparent in the Gulf of Carpentaria. A trough lies through central
Australia ahead of a front moving through the Bight. The high to the west is ridging
along the southern coast of Western Australia near to 35°S with a broad westerly flow to
its south through the Bight. Discussion: The trough and front will move through the southeastern states Friday night and during Saturday and may stall during Sunday. The high will move away through the Tasman Sea, strengthening and building a ridge along the Queensland coast. The upper trough near the southeastern Queensland coast is likely to remain in the area during Saturday. The trough over the northwest of the continent will extend southwards inland of the west coast, encroaching upon the ridge lying along the southern coast. A persistent patch of midlevel moisture over the Kimberley will linger. A satellite low on the western side of a deep low in the Southern Ocean (948hPa) will move northeast through the western Bight, but is unlikely to affect the southern coast apart from the passage of the front associated with it. Areas to watch: an area of mid and upper vorticity exists along the front moving through the Bight on Friday night. Rainfall potential |
| 20 | . | Overview: The high
remains slow moving near the head on the Bight influencing the weather over much of the
continent. The deep southwesterly flow between the low south of Tasmania (946hPa at
10amEST) and the high in the Bight has continued to affect Tasmania during Thursday with
heavy snowfalls to very low levels, with snow also falling over the mainland alpine
resorts. A low in the western Bight extends a front through the southwest of Western
Australia. A trough lies over the Top End with a weak infeed of tropical moisture
over the Kimberley and northwest Territory. Discussion: During Friday the nigh in the Bight will move across eastern Australia bringing settled weather to much of the eastern states. The weak front to its west will move through Western Australia and much of South Australia tonight and tomorrow with northwesterly winds, strengthening over Tasmania ahead of this system bringing a return to mild to warm conditions. The north of the continent will remain under the influence of a weak trough with the next high ridging in to the west along the southern Western Australian coast. Rainfall potential |
| 19 | . | Overview: Strong to
galeforce winds have been widespread throughout Wednesday across southeastern Australia.
Gusts to 148kmh at Cape Grim (Tas) & gusts to 144kmh over the mainland alpine
areas and along exposed coastlines were recorded. Showery conditions with isolated hail in
a deep southwesterly flow (100knots at 500hPa - 18500') have established across the
southeast during Wednesday. Snow to low levels in Tasmania on Wednesday night. A broad
pool of very cold air covers much of the eastern Bight, Tasmania and the southern Tasman
Sea. An area of weak vorticity off the New South Wales coast early Wednesday has moved away to the east. A broad trough extends across the north of the continent with a weak mid-level infeed of moisture into the northwest Top End, with a ridge pushing along the southern coast of Western Australia. This ridge is directing the southwesterly flow and embedded fronts northeast towards the southeast of the country. Low pressure systems follow the high ridging into the west near to 40°S. Discussion: The ridge of high pressure will bud off to form a cell near the head of the Bight with a ridge to the south. The deep southwesterly flow across the southeast will moderate during the day as the high moves further east. Snow over higher parts, especially Tasmania will fall to low levels tonight, becoming less frequent during Thursday. A front will cross the southwest of Western Australia. Much of the north of the continent will remain fine with the exception of the Kimberley area which sees a weak mid-level infeed of moisture from the tropics. Rainfall potential |
| 18 | . | Overview: A front is
moving through New South Wales followed by a cooler southwesterly flow across the
southeast of the continent. A broad area of high pressure is ridging through southern
Western Australia and a strong and deep band of westerlies lies to its south through the
Bight. A number of fronts is embedded in the westerly flow. A trough remains over the
northwestern Top End with some infeed from the tropics, and can be traced to the southeast
corner of Queensland, but remains dry through the inland parts. A low is approaching the
western Bight near to 35°S. Discussion: The trough moving northeast through New South Wales an Queensland will move offshore during Wednesday morning with showery conditions clearing. There are signs of vorticity within this trough off the New South Wales coast. The high in the west will ridge northeast across the continent during Wednesday, with the westerly flow becoming more southwesterly and a front also affecting the southeastern states. Very strong winds are likely with showers developing. The low in the west will pass south of Western Australia. Areas to watch: keep an eye on the very strong upper jet moving through the Bight which is showing speeds in excess of 180knots and looks to move across the southeast of the continent during Wednesday. Rainfall potential |
| 17 | . | Overview: The high in
the Tasman Sea has remained quasi-stationary with a ridge extending along the Queensland
coast. A complex trough extends from the far southeast of the country to the western Top
End and is followed by a strong thermal trough with a broad area of very cold air in
the lower layers extending across the central and eastern Bight and onto the southern
coast. Moderate falls over much of the southeast have been triggered by this trough,
as well as very strong to damaging winds. A large high is moving onto the southern Western
Australian coast, bringing clearing conditions to the west. A deep westerly flow is
forming to the south of this high. Discussion: The high in the Tasman will move away during Tuesday, with the ridge along the Queensland coast weakening. The northern end of the trough through the country will continue to linger over the Kimberley - western Top End while the southern portion moves through New South Wales and Queensland. Showers, tending to rain periods with embedded storms are likely within the trough. Colder conditions will prevail over the southeast with snowfalls developing over alpine areas (both on the mainland and Tasmania) during Monday night or Tuesday with hail likely near to the coast, mainly on Monday night. Winds in the southeast will moderate somewhat and turn westerly, before restrengthening later Tuesday and into Wednesday. The high to the west will move along the southern Western Australian coast, while the West Australian trough will begin to reform near to the west coast. The deep westerly flow developing to the south of this high will affect Tasmania and the southeast of the continent later Tuesday and into Wednesday. Areas to watch: keep an eye on the upper jet just making an appearance to the southwest of Western Australia which is showing speeds of 180knots and looks to move across the southeast of the continent in the next 2-3 days. Rainfall potential |
| 16 | . | Overview: The low in the
central Bight has deepened to 981hPa, with a front and prefrontal trough extending into
South Australia. Very strong winds have prevailed across South Australia and much of
Victoria during Sunday with blowing dust in the west and snowmelt over the alpine areas.
The high in the Tasman extends a ridge along the Queensland coast, while to the west of
the continent another high is approaching with a ridge extending through the Bight and
south of the low. The thermal (cold) trough over the southwest of the Western
Australia behind the front has triggered widespread light showers with some hail. The trough extending from the north to the south of the continent has remained anchored near the Kimberley and western Northern Territory while moving east over the southern parts. The Tasman Sea sees the lower levels under the influence of a high while the upper levels remain influenced by a trough lingering off the southeast Queensland coast. Convective cloud generated near the Solomon Islands is being carried to the southeast by the jet, responding to a deepening low (945hPa 10am 15/09) well to the east of New Zealand. Discussion: The low in the Bight will move southeast during the next 24 hours, while the front, which is moving faster than the prefrontal trough and is likely to combine with it, will move through Victoria and western New South Wales on Monday (and Tasmania later Monday) preceded by strong to galeforce northerly winds tending west to southwesterly and moderating later. Showers are likely to become widespread with some reasonable falls possible. The high in the Indian Ocean will approach Western Australia near to 35°S and bring clearing conditions, while to its north the trough extending through the Northern Territory will likely become broader and extend eastward towards the Gulf Country. The ridge from the Tasman high along the Queensland coast will direct southeasterlies onto the coast with scattered showers.. Rainfall potential |
| 15 | . | Overview: The low that
has moved into the western Bight southwest of the continent has moved only slowly through
Saturday while deepening slightly. Very strong winds, both at the surface and in the
middle levels are associated with this system. A strong thermal (cold) trough to the west
of the surface feature is beginning to wrap cold air around the northern part of the
trough. To the east, a quasi-stationary midlevel trough extends from the western Top End
to the Bight (tilting as the southern part is moves east faster than the northern part).
The slow moving high over the Tasman Sea extends a trough along the Queensland coast. The
upper trough continues to linger just off the southeast Queensland coast, and has
also remained slow moving through Saturday. Discussion: The high ridging into our longitudes will maintain the ridge to the southeast, helping to slow the southeasterly movement of the low in the Bight, and may even cut it off from the westerly flow to its south. Strengthening north to northwesterly winds across South Australia and the southeastern states through Sunday will bring warmer conditions ahead of this front. Very strong winds are possible with this system, and there will continue to be a steep east - west temperature gradient helping to maintain the strength of the front. This southern part of the trough through central Australia will slide east, while the northern end will remain over the Kimberley and western Top End. The high in the Tasman will maintain the ridge along the Queensland coast, and the upper trough will continue to linger in the area, with showers likely over much of the eastern coast north of 30°S. Areas to watch: The strong frontal system moving across the southwest of the continent Saturday night may catch up with the moisture associated with the slow moving trough through central Australia. If this happens, rainfall totals may be moderate to good over a large part of southeastern Australia early in the coming week. Rainfall potential |
| 14 | Clyve Herbert | An interesting cloud band extending from near Darwin to the head of the Bight is rather unusual, appears to be convection affecting the mid levels and the presence of a weak trough. |
| 14 | . | Overview: This past week
has seen a dramatic change in the synoptic setup through our longitudes - we have
progressed from snow to low levels in Tasmania to showers over the Top End and a
persistent trough over northern Australia - spring and its rapid changeability is come!
Heavy showers over the Darwin area (up to 42mm), surface dewpoints in the double negatives
(ie: very dry air) over Victoria while the air at higher levels was saturated for ice and
conducive to the formation of contrails, 30°C at
Giles and snowmelt over the alpine areas. The high over New South Wales moved east through Friday with a ridge remaining along the Queensland coast. The trough over northwestern Australia triggered occasional showers over the Kimberley, western Territory and Top End. A complex low lies well to the south of Western Australia, with associated fronts grazing the southwest corner during Friday. Discussion: The high will strengthen as it moves over the Tasman Sea with the ridge remaining near to the coast through Queensland. The trough moving east through the state will slow and possibly stall through Saturday. Strengthening north-northwesterly winds over the southeast of the continent during Saturday and Sunday will increase both temperatures and the rate of snowmelt. A satellite low developing in the cold air southwest of Western Australia looks likely to move northeast towards the Western Australian coastline during Saturday, bringing very cold air from the Southern Ocean around its western side as the upper trough deepens. This low will pass through the western Bight just to the south of the state. Areas to watch: the area of convection near the Solomon Islands is moving southeast with the upper jet which feeds into a deep trough well east of New Zealand. This pattern is, in theory, similar to that of last year, which helped keep much of the Coral Sea clear of of TC activity. Rainfall potential |
| 13 | . | Overview: The high
drifting across eastern Australia near to 35°S has remained slow moving through Thursday
and extends a ridge along the Queensland coast. A broad trough over northern
Australia has a southward extension through South Australia which has been triggering
light to moderate falls with a band of storms to the west of the main rain area through
the centre of the continent. This trough extends through the Bight to the Southern Ocean
and is east of the next ridge which crosses the west coast near 30°S. The trough moving along the northeast New South Wales / southeast Queensland coast triggered isolated storms during Wednesday night and Thursday morning. A very large active trough (with a surface low of 947hPa at 10am EST) is located in the southern Indian Ocean to the southwest of Western Australia. Discussion: The active trough through central Australia will move slowly in a generally east to northeast direction across New South Wales and Queensland under the influence of the upper jet. The high over New South Wales will move little through Friday with mainly fine conditions in the east and increasing high and middle cloud in the western part of the eastern states, but little rain is likely as the trough weakens out. Northwesterly winds ahead of the trough through Victoria will bring a steady rise in temperatures, with snowmelt in the alpine areas becoming probable. The trough over the northwest of the continent will remain through Friday with lingering moisture sufficient for isolated storms possible in the Kimberley and western parts of the Northern Territory. The front approaching the southwest corner will bring showers tending to rain periods with a deepening upper trough and colder conditions to follow. Rainfall potential |
| 12 | Clyve Herbert | Along comes an interesting and large cloud band through central Aus and as far south as northwest Vic, seems to be associated with mid and upper level baroclinic tendencies coupled with an upper trough. |
| 12 | . | Overview: The high in
the Bight has moved very slowly through Wednesday and lies near Mt Gambier, influencing
conditions over continental southeastern Australia. A trough extends through the
Tasman Sea to the northeast New South Wales / southeast Queensland coast to an upper cold
pool over the northeast coast of New South Wales, a combination which has been triggering
widespread scattered storms through Tuesday night and today. The trough over Western Australia has deepened through the day and bisects the baric ridge, while the trough currently moving through the western Bight has also intensified during Wednesday afternoon. Moisture from the northeast across Papua-New Guinea is moving onto the Australian continent over the Top End then feeding southward into the trough moving over the Western Australian Interior and Goldfields areas. There is also a moisture infeed from the Indian Ocean Discussion: The high will drift across eastern Australia bringing very cold conditions overnight to the southeast of the continent. The trough extending to the east coast will move northeast through Thursday, triggering showers and storms through southeastern Queensland - the cold pool is also likely to move north-northeast. The infeed of moisture across the Arafura Sea and the Indian Ocean will continue with showers and isolated storms developing as the trough moves east through South Australia during Thursday. A front ahead of a large cold airmass in the southern Indian Ocean is approaching the southwest of the continent to the south of the next ridge. Rainfall potential |
| 11 | Matt Pearce (NSW) | EC has downgraded the intensity of the
thermal gradient across the front, GASP has intensified its post-frontal cold pool and
therefore its thermal gradient, and also slowed down the eastwards movement, and AVN has
also slightly intensified. AVN seems to be very similar to GASP in the rain
totals/locations it is progging. Somehow I do not think there will be as widespread high
totals as is being progged by these models as there does not appear to be the tropical
moisture infeed needed for a substantial cloudband. However, areas on the
northern/northwestern side of the ranges in VIC and NSW(including Alpine areas) could see
some substantial orographically assisted totals(eg 50mm+) from Sunday to Tuesday. Other
inland areas may see 5-10mm during this time. The system then looks like it might degenerate into a replica of what we have just had by mid next week, with a cold SW burst moving up across the mainland, associated with little moisture. |
| 11 | . | Overview: The high in
the western Bight has drifted east during Tuesday to be located in the centre of the Bight
late in the day. A deep southwesterly flow directed over southeastern Australia has
resulted in snow falls to low levels in Tasmania with snow over the mainland resorts. An
upper jet (located between 350 - 600hPa levels*) continues to move across the continent
and is marked by cloud stretching from near Perth to north of Brisbane. A trough extends through the Tasman Sea along the Queensland coast, with the atmospheric setup over eastern Australia further complicated by an upper trough. A cross-equatorial surge of moisture across Indonesia is turning southeast toward our northwest coast. The West Australian trough is located inland of the west coast and is drawing moisture in from the Indian Ocean. Discussion: The high will drift across the southeast of the continent during Wednesday, with very cold conditions and widespread frosts. Scattered showers along the east coast will contract northward through Wednesday with the northeastward movement of the upper trough. The Western Australian trough will bisect the baric ridge as it deepens southward toward the south coast ahead of the approaching upper trough. A front further west is stronger and is associated with a complex and deepening surface low (950hPa 10amEST) and upper trough. Rainfall potential *350 - 600hPa = ~4350 - 8450mASL in the west to 3700 - 8000mASL in the east. |
| 10 | Nick Sykes | EC has really strengthened the system due through Victoria on Sunday and is predicting some extremely strong winds with and ahead of the fornt. This system has Monday of last week written all over it, wind wise, with the possibility of severe winds. Looks like a huge northerly fetch ahead of this system so moisture from the north looks likely, combined with the warm airmass, we could see some storms as well, and some good rain. |
| 10 | . | Overview: A weak trough
(more an area of generally lower pressure) occupies the northern part of the continent,
with the high ridging into the Bight to the south of Western Australia. A deep
southwesterly flow has pushed colder air across the southeast of the country, but the
inversion and little available moisture in the midlevels has limited precipitation,
especially over the continent. A broad upper trough lies to the south of the Bight. Falls
of sleet and hail have been reported along the higher parts of the Victorian ranges with
light snowfalls over the higher parts of the alpine areas. The baroclinic area that formed
over central Australia during the weekend has continued to drift east with the jet and the
Queensland coast has seen scattered showers and storms later in the day. Discussion: The high will move east through the Bight during Tuesday and send a ridge to the east. To its west, the trough over Western Australia will dip south to lie along the west coast ahead of a front moving into the southwest. West to southwesterly winds will moderate over the southeast of the continent although Tasmania will continue to experience strong to galeforce winds, particularly in the west during Tuesday. A broad and cold airmass will continue to influence the southeast through Tuesday with continuing showers and cold conditions, particularly in the south. Patchy showers are likely along the exposed parts of the Queensland trough, especially near the baroclinic area moving across the coast. Rainfall potential |
| 9 | . | Overview: A weakish
surface ridge of high pressure has edged across the south of the continent to central
South Australia. A broad trough covers the north of the continent, interrupted by a 'very
small' high in the Gulf of Carpentaria!! A complex low southwest of Tasmania is
moving east with a cold front to cross both the southwest of Western Australia and
southeastern Australia during the next 24 hours (the alignment of this front is WNW -
ESE). The trough has moved (almost) off the Queensland coast, but is lagging along the far northeast coast. The high in the Indian Ocean has slipped south and is now ridging towards the western Bight. There has been an increase in atmospheric moisture over much of Western Australia and South Australia during the weekend and the area of baroclinic instability that became apparent during Saturday has expanded and drifted generally east with showers and isolated storms in southern parts of the Territory during Sunday. Discussion: Cyclogenesis during Monday on the western side of the current low in the Bight will bring much colder conditions to the southeast as air from the Southern Ocean is directed towards the southeast of the continent. The high ridging into the western Bight while also ridging southwards will assist this cold advection. Lower pressures will continue over the north of the continent in a broad trough, with showers over Cape York and the northeast of the Top End. The trough over central Australia will continue to drift generally east, triggering showers over western parts of (mainly southern) Queensland. Areas to watch: There is a risk that some of this moisture (on the southern edge of the baroclinic area) may be drawn into the frontal system currently moving through the Bight as it passes over eastern Australia. Rainfall potential |
| 8 | Matt Pearce (NSW) | Starting in TAS tomorrow, then VIC Mon/Tue and NSW Tue/Wed/Thu. It will definitely be cold enough for snow to low levels...it is just an issue of whether there is enough moisture around. TAS will obviously fare the best on this front, with the mainland struggling to get anything from the southwesterlies. The NSW coast has the potential to get a few showers depending on the direction of the winds. GASP originally was hinting at a strong southeast flow with a substantial upper trough which would have produced quite a nice rain event. However, it has now fallen more into line with the other models in taking the high further north across NSW, rather than through Bass Strait. For this reason, I think most of the showers will be restricted to the coastal fringe, if they even get that far. It should be quite cold and cloudy though on Tue and Wed in Sydney. |
| 8 | . | Overview: The high in
the central Indian Ocean remains quasi-stationary while extending a ridge further onto the
continent than during the past fortnight. The trough through Queensland has triggered
storms near the coast in the southeast during the afternoon and evening. This trough is
linked to the heat trough over the northwest of the continent. A front crossed Victoria
and Tasmania and is moving along the east coast on Saturday night. Another in the series
of satellite lows is moving northeast through the Bight around a low in the Southern
Ocean. Another series of lows and fronts is moving towards the southwest of the
Bight, but may pass slightly further to the south and through the Bight rather than across
the continent. An increase in the moisture availability across the northern part of the continent is partly the result of a broad cross-equatorial flow extending from the Coral Sea west to Indonesia. Discussion: The broad upper trough will remain to the south of Australian latitudes, with cold air continuing to be driven north through the Bight. A weak ridge will bud off from the main centre which is likely to remain in the central Indian Ocean. A front will affect the southeast of the country during later Sunday, continuing the cool unstable westerly flow across these latitudes. The baroclinic cloud over Western Australia looks to be on the southwest side of the upper jet, but with the moisture feeding into the area from the northwest, should be monitored as it drifts east. In summary, Sunday is likely to see showery conditions over the southeast, a slow moving trough over southern and central Queensland, increasing atmospheric moisture over the north of the continent and snowfalls over the alpine areas, with snow levels lowering overnight Saturday and early Sunday. Rainfall potential |
| 7 | Nick Sykes | After this mornings look through the models it continues to look quite promising for a cold outbreak Monday/Tuesday of next week in Victoria. Thickness values around the 532 mark and 850 temperatures around the -4 mark (cold). |
| 7 | . | Overview: That closed
low over the Gulf of Carpentaria has reappeared!! The trough continues to lie through
eastern Australia with a strong ridge along the Queensland coast from the stationary high
north of New Zealand. A trough passing through southern and central New South Wales has
triggered isolated storms over the Southwest Slopes and Central Tablelands during the
afternoon. A satellite low of 970hPa in the Bight is moving to the south of Tasmania and the front extending northwards is approaching southeast South Australia and Tasmania. A weak heat trough lingers over northwestern Western Australia while the high in the Indian Ocean continues its attempt to ridge along the southern coast. Discussion: The blocking pattern which has kept a series of ridges and troughs moving through the southern parts of the country has begun to unlock during the last 12 hours. The trough over eastern Australia will move to the northeast as the high near New Zealand moves away and the ridge along the Queensland coast weakens. A front will cross the southeast of the country Friday night / Saturday morning followed by a deep west to southwesterly flow with cooler, showery conditions to follow. The Indian Ocean high will attempt to ridge into the continent and it looks likely to bud off a weak area of higher pressure while the main centre moves slightly east of its current location. The lows and troughs may begin to move through our area at higher latitudes as the high approaches the continent, while in the south of the Bight, the upper trough will also begin to edge east. Rainfall potential |
| 6 | . | Overview: A front
crossing southeastern Australia during Thursday night extends from a low of 951hPa
(10amEST) in the far southern Bight to near 30°S preceded by strengthening northwesterly
winds. The trough over New South Wales, into Queensland has remained quasi-stationary
during the last 72 hours, with an immobile high just to the north of New Zealand ridging
firmly along the Queensland coast and halting its progress. Moist infeed over the Top End,
as well as another weak infeed from the Indian Ocean to the northwest has helped maintain
shower and storm activity within the trough through Thursday. Another immobile high in the central Indian Ocean extends a ridge into Western Australia near to 30°S. These ridges weaken over land, and a series of fronts continue to slide along the southern side of the ridge, then interrupting the baric ridge to its east. The upper longwave trough remains over our longitudes. Discussion: There will be little movement of the major synoptic systems during Friday, with areas to the south of 35°S continuing to experience a progression of fronts, with satellite lows forming in the Bight and moving around the broad trough. These fronts bring waves of colder air to the southeast, especially in the middle levels, destabilising conditions as the fronts pass with showers and isolated storms resulting. The high in the Indian Ocean will continue to weaken slowly with a ridge remaining along the southern coast of Western Australia. The trough over Queensland and New South Wales will remain quasi-stationary in its eastward movement (although ambling about the eastern part of the continent as the pressure fields surrounding it shift), trapped by the ridge along the coast. An upper cold pool is likely to destabilise conditions further within this trough, and may move southeast during the day. Scattered showers and storms are likely to continue through Friday, with some large storms possibly developing nearer to the coast and ranges. Rainfall potential |
| 5 | . | Overview: A ridge
extending from the high north of New Zealand along the Queensland coast, has stalled the
eastward movement of the trough over northeastern New South Wales and Queensland. A front
through the southeast of the country later Wednesday triggered scattered showers,
spectacular sunsets and isolated storms, with sleet and some snow over higher parts of the
alpine areas as well as heavier falls over the resorts in Tasmania during the afternoon
and evening. A deep westerly flow around the northern edge of a broad upper trough to the south of the Bight is bring showers to exposed coastlines. Another in the series of fronts is approaching southwest Western Australia, while the quasi-stationary high in the Indian Ocean maintains its ridge (although weakening) just to the west of the continent - the westerly pattern that is dominant at present is preventing the high from building strongly across our longitudes. Discussion: The ridge along the Queensland coast will maintain the trough across the state through Thursday, while the southern extension will move northeast out of New South Wales. The high in the Indian Ocean will send a budding ridge into the south of Western Australia during Thursday, with a series of fronts and colder air directed northeast from the southwestern Bight in the southwesterly flow to affect the southern states. Tropical moisture from the Arafura Sea will feed into the trough over Queensland, with increasing cloudiness over the Northern Territory mainly over the Top End, and scattered showers near the coast.. Areas to watch: An area of moderate convection over the northeastern Coral Sea is edging southwest, with a convergence line of upper cirrus to its northwest (across Papua) mirroring its movement. There is also a cross-equatorial surge of midlevel moisture over Indonesia which is turning to the southeast, and should be watched. Rainfall potential |
| 4 | . | Overview: The high in
the Indian Ocean remains quasi-stationery and continues to steer troughs towards the
Australian continent. The low in the southern Bight has deepened to 944hPa, with a further
group of lows to its southwest at 950 - 960hPa being steered along the southeastern side
of the high. Very cold air follows the front approaching the southeast during Tuesday
night as evidenced by the convection over the Bight and the broad thermal (500hPa) trough
to the west of the low. The trough and frontal system which was responsible for galeforce
winds through Victoria on Monday night is moving through New South Wales, triggering
showers and storms in northern New South Wales and southern Queensland. Discussion: Wednesday is likely to see the trough move slowly through Queensland with further showers and storms generated. The slow moving high to the east of New Zealand will continue to maintain a ridge along the Queensland coast, which will slow the eastward movement of the trough. The broad upper trough to the south of Australia will help to encourage the movement of further troughs and fronts to the northeast through the central Bight with showery conditions likely to continue along much of the southern coast and across Tasmania. Areas to watch: The large area of low cloud over the southern Indian Ocean can be traced around the globe. Rainfall potential |
| 3 | . | Overview: A strongly
baroclinic area lies ahead of two strong fronts moving through the eastern Bight
Monday evening. Storms within this area, are more frequent in areas of full depth, rather
than midlevel (between ~750 and 520hPa) moisture, and closer to the fronts. In the Bight a
deep low (949hPa) has a satellite low (960hPa) to its northeast with an attendant front,
while the first front extends from a low (954hPa) near Antarctica to near 25°S. A weak ridge of high pressure lies over the east coast near to Brisbane, while the remnant trough over inland Queensland (connected to the low in the eastern Tasman) is also connected to the upper outflow from the baroclinic area over southeastern Australia. Discussion: A series of troughs and fronts will cross southern Australia during the next 24 - 36 hours. Strong north-northwesterly winds will shift westerly and later southwesterly during Monday night - Tuesday. Scattered storms are likely overnight Monday across the southeastern states, with areas of patchy rain developing with scattered storms continuing. Snow showers are likley to develop over the alpine areas Tuesday. The slow moving high ridging towards Western Australia near to 25 - 30°S is likely to maintain the pattern of the last few days, steering troughs and fronts northeast from higher latitudes towards the mainland. Areas to watch: a very large area of low cloud over the Indian Ocean to the southwest of Western Australia appears to be associated with the interaction between the large high and a front to its east. Unusual! Rainfall potential |
| 2 | . | Overview: Cyclogenesis
occurred overnight - a cold pool and low now located off the coast of New South Wales
extending a trough northwest through Queensland. A ridge is moving across the southeast of
the continent during Sunday afternoon and evening followed by a large and complex surface
trough moving through the western Bight followed further west by a thermal (500hPa)
trough. Pressure gradients at the surface are tightening over this area. During the past few days, the upper circulation across our longitudes has become strongly meridional. The alignment of the high (positive longitudinal) in the Indian Ocean (which is strengthening slowly) continues to direct lows along its southern side and towards the Australian continent. Discussion: The satellite low to the south of Western Australia on Sunday night will continue to move around the deep low in the southern Bight and move southeast through Monday. A series of fronts will move east through the Bight and begin to affect South Australia during Monday, and Victoria and Tasmania later in the day, with strengthening northwesterly winds ahead of the system bringing very mild temperatures to the southeast. To the west of these fronts, a deep west (becoming southwesterly) flow will bring showers tending to patchy rain to much of the southern parts of the continent and Tasmania with snowfalls developing after Monday. The slow moving high in the Indian Ocean will continue to direct troughs along its southeastern side and to the northeast during the next few days - the development of a ridge to the southeast will also help. Areas to watch: the first 'serious' convection to the northeast of the Solomon Islands should be noted Rainfall potential |
| 1 | . | Overview: A trough, with
a front moving through Bass Strait and southern Victoria, extends north to New South Wales
from the low in the southern Tasman Sea to the southeast of Tasmania. A high to the north
of New Zealand extends a ridge along the Queensland coast. Pressures generally have begun to decline over northwestern Australia and there is a buildup of moisture north of 15°S over the Top End and the Kimberley area. A strong low (962hPa at 10am AEST) is passing to the south of Western Australia with a front approaching the southwest of the continent. The Indian Ocean high has strengthened and continues to ridge into our longitudes near to 20°S. Discussion: As the surface trough and associated upper cold pool drifts eastward during Saturday night / Sunday it is likely to show signs of cyclogenesis as it moves off the coast. A weak ridge will follow it across the southeast of the continent. The front crossing the southwest of Western Australia will trigger widespread shower activity extending along the west coast to near Northwest Cape with isolated storms likely, mainly in the south. Galeforce winds are likely in the northwest quadrant of this low as it deepens. Rainfall potential |
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