Victoria - May 2002 Forecast Outlook, Discussion & Report Page



May 2002 Forecast Outlook, Discussion & Report Page Victoria
Date	Name	Information
		June Forecast Outlook, Discussion & Report page
31	.	Overview: The low has moved off the New South Wales coast and is located in the Coral Sea, directing an onshore flow onto the state. This low is mirrored through the upper levels and is directing a deep, but very slack E-SE flow across Victoria. The high has strengthened in the western Bight and is located near to Esperance. The pressure gradient over the north remains slack, while Upia is now a low. The front crossing the southern parts of South Australia is triggering storms about the Eyre Peninsula while an upper high over Western Australia stabilises conditions over much of the state. The next longwave trough to the southwest of Western Australia is identified by a large strong cold air field. Discussion: The high in the Bight will edge northeast along the coast (like the last one did) with a southwesterly flow being directed across South Australia, Tasmania and Victoria behind the front, triggering showers. This high will remain slow moving and will dominate most of the country's weather over the next couple of days. The southwest of Western Australia will feel the influence of the next trough - front combination approaching as part of the longwave trough later Friday / Saturday. The low in the Tasman Sea will move only slowly southeast, while a wave low along the front crossing the southeast corner may develop west or southwest of Tasmania early Friday. Rainfall potential Victoria: Showers developing in the west Thursday night, spreading throughout during Friday. Scattered showers to follow with light snow on higher parts of the Alps. NSW: Showers along the coast, becoming confined to the coastal fringe & becoming less frequent through Friday. Widespread fogs, with frosts over higher parts. Showers developing in the southwest and south and moving east. Isolated storms. Snow possible over the Alps behind the front. Queensland: Mainly fine. Widespread frosts inland. NT: Fine throughout. WA: Fine in the north. Drizzle patches along eastern parts of the south coast. Showers developing in the southwest later Friday or Saturday. SA: Widespread showers in southern parts moving through Thursday night to be close to the northeast of the state and into Victoria during Friday. Storms over Eyre Peninsula becoming confined to the northeast of the state during Friday & more isolated. Tasmania: Showers, widespread developing Thursday night and spreading throughout during Friday.
30	.	Overview: A complex surface pattern tonight with the weakening high following the coastline of the Bight and extending a ridge through the Tasman Sea with a wave low and front located southwest of Kangaroo Island moving southeast. Another trough and weak front to the west will follow. New South Wales remains under the influence of a wandering upper level low which crossed the coast of South Australia last week and today continues its direction-changing journey through south-central New South Wales. The trough along the northeast coast of New South Wales has deepened. Pressure gradients over the north of the continent remain weak. TC Upia has weakened and is moving southeast. Discussion: The high will strengthen to the west of the Bight and allow a series of weak fronts to cross southern Australia during the next day or two. The upper low over New South Wales is likely to move off the coast during Thursday, and in conjunction with the ridge from the high in the Bight, looks to set up a deep onshore flow which may trigger widespread showers in coastal regions and along the nearby ranges. Heavy falls are possible. A shortwave trough and surface front will move through South Australia and Tasmania during Thursday increasing showers in those states, and into western Victoria later in the day. A broad longwave trough is approaching from the west, but is at higher latitudes that the last series, and is unlikely to introduce significantly colder air directly to the Australian continent. Cold air in the middle levels however, is likely to be brought north across the southeast corner. This air is returning from the New Zealand area and, dependant upon the strength and mobility of the upper low, may reach near to 30°S courtesy of the jet which is likely to strengthen around the upper lows. Rainfall potential Victoria: Widespread fogs, with frosts over higher parts, clearing. Showers developing in the southwest later. NSW: Showers along the coast, extending inland to the ranges. Storms are possible as are heavy local falls. Cold nights inland with fogs, and frosts over higher parts. Queensland: Showers in the southeast corner with isolated storms possible becoming less frequent. Fine elsewhere. NT: Isolated showers possible over the northwestern parts of the Top End. WA: Isolated showers along the south coast, clearing to only drizzle patches in the southwest. SA: Showers developing in the west and south during Thursday after widespread fogs. Tasmania: Showers in the west, extending to the south during the day. Frosts over higher parts.
29	.	Overview: The high in the Bight is quasi-stationary and the baric ridge has edged further south again. The upper cold pool that crossed the South Australian coast has described a shallow curve through northeast South Australia and New South Wales and has triggered storms, particularly in the Hunter with hail reported on the Central coast. This upper low has ensured that Victoria has had a deep (surface to 200hPa) ~ESE-E flow keeping moisture levels high. TC Upia has maintained its integrity through the day. The sub-tropical jet can be traced by the upper cloud through central parts of Western Australia. Cooler air at 850hPa is now getting well into the tropics. Discussion: The high will be edged northeast during Wednesday towards the South Australian coast and a series of fronts will pass well to the south. Much of southern Australia will be affected by this large high, bring colder nights away from the coast. The pressures over northern Australia will remain relatively low, and some showers may be triggered in the east Pilbara and Kimberley by the cloudband carried in by the jet. Showers will remain likely along much of the east coast, a combination of the trough moving east and the moist onshore flow set up by the broad ridging along the east coast. The trough, over northern New South Wales on Tuesday night, is showing signs of vorticity and once off the coast, may deepen. TC Upia is likely to weaken and move southeast. Rainfall potential Victoria: Frost in the north with widespread fogs. Showers along the south coast, mainly in the east. Fine elsewhere. NSW: Showers with some heavy falls developing, mainly along the central and north coasts & adjacent ranges, with isolated storms during Wednesday. Widespread fogs, with frost over higher parts. Queensland: Isolated showers along the east coast, mainly in the south. NT: Mainly fine. WA: Possible light showers in the east Pilbara and Kimberley regions. Drizzle patches along the south coast, mainly in the west. SA: Isolated showers developing on the south coast later. Widespread fogs in the south. Tasmania: Scattered showers in the south,decreasing through Wednesday. Widespread fogs, frost over higher parts.
28	.	Overview: The high in the Bight that weakened to allow the low to amoeba to the northeast across the South Australian coast, now ridges to the south and will help steer approaching systems across the southern coast. A tornado & waterspout have been reported from southeast South Australia. Lows in the upper levels have moved northeast through South Australia and into western New South Wales with Victoria feeling the effects of their proximity with low to mid-level convection in the south and west. A ridge extends along the east coast to the tropics with a trough running down the west of the ranges in Queensland. TC Upia remains at 995hPa near the eastern tip of Papua. The pressure gradient through the northern part of Australia remains weak and the baric ridge in the west remains at ~30°S. Discussion: The high in the Bight will remain slow moving to the northeast and will strengthen slightly while the ridge along the east coast is likely to broaden, weakening the trough through Queensland currently west of the ranges. TC Upia looks to move to the southeast through Tuesday and weaken as it enters an area of stronger shear. The trough over the west coast will move eastwards through Tuesday, crossing much of the state, but looks to be largely inactive. Tropical moisture feeding across the west coast from the Indian Ocean my trigger isolated showers in the Pilbara. The surface low over South Australia will weaken at the same time as the upper features weaken while the entire system moves northeast through New South Wales triggering showers. The southeasterly - easterly surface - middle level flow across Tasmania and Victoria will continue to trigger showers, with cooling in the mid levels enhancing convection & steepening lapse rates. Snowfalls to low levels are likely to in the South Island of New Zealand, with gales in the north. Rainfall potential Victoria: A cold night inland with widespread fogs, with some frosts. Scattered showers, mainly in the south. NSW: Isolated showers, mainly along the south coast. Scattered showers inland spreading to central parts with isolated storms. Queensland: Showers, with isolated storms in the southeastern corner, and along the tropical and central coasts, becoming less frequent through Tuesday. Showers west of the ranges in central parts with isolated storms moving coastward. NT: Fine. WA: Isolated showers possible in the Pilbara, spreading inland at times. Fine elsewhere with the exception of some drizzle along the southeast coast. SA: Isolated showers in the south, scattered showers and isolated storms in the northeast, becoming less frequent. Widespread fogs in the southeast. Tasmania: Showers in the south and east. Widespread fogs with frost over higher parts.
27	.	Overview: The high in the Bight has weakened through Sunday and allowed the low to migrate northeast. A weak ridge extends along the east coast. TC Upia has become organised near Papua and is moving southwest. A front is approaching the southwest of Western Australia associated with the next longwave trough,, while cloud crossing the coast near Geraldton marks a strengthening jet.. The high moving in at ~30°S will strengthen as it moves east. Discussion: The high in the Bight should remain weak and quasi-stationary through Monday. The surface low in the Bight looks to continue its northeast trajectory through Monday as will the upper lows, with a cold pool in the middle levels crossing the SE South Australia / western Victorian coast during Monday. Moist onshore flow along the east coast directed by the ridge will continue to trigger scattered showers over northern New South Wales and Queensland. Conditions over the northern parts of Australia will continue showery over the Top End as well as tropical Queensland. Upper shear in the Coral Sea may cause a problem for TC Upia as the system moves southwest. The front approaching Western Australia should begin to slide southeast through the Bight after crossing the far southwest. Image of low southwest of Adelaide Rainfall potential Victoria: A cold night with widespread fogs, with frosts over higher parts. Isolated showers along the southwest coast clearing then redeveloping in most areas south of the ranges during Monday. Thunder a risk. NSW: Scattered showers along the coast mainly in the north. Queensland: Scattered showers along the northern tropical coast with isolated storms developing inland. Isolated showers in the southeast corner clearing. NT: Scattered showers over the Top End, mainly in the northwest. WA: Scattered showers in the far SW with isolated showers in the Geraldton area. Drizzle along the south coast clearing as a ridge builds. SA: Widespread fogs. Showers developing in the south and southeast. Isolated storms are possible. Tasmania: Isolated showers in the south and west. Cold night. Widespread fogs with frosts over higher parts.
26	.	Overview: The high to the southwest of Tasmania has remained quasi-stationary through Saturday and is slowing the low in the Bight, while extending a ridge through the Tasman Sea. A broad trough occupies most of eastern Australia all the way to the tropics of Queensland, with a trough also through the west (still looks like a 'summer synoptic'). A broad upper trough is approaching the southwest of Western Australia. The upper flow across the north of the continent remains highly zonal, while southern parts are under a more meridional flow, which is reflected by the surface pattern being more 'complicated' in the south. The area of convection near the Solomon Islands has moved WSW but is struggling to become better organised. Discussion: As the high in the Bight weakens through Sunday and extends a ridge to the southwest, the low may begin to move east or northeast although it looks to remain weak at the surface. The upper low that this surface feature is associated with will move northeast towards the southeast corner during the next day or so. Weak flow over the north of the continent will continue during the next few days, with the unusual moist southwesterly mid-level flow along the Pilbara - Kimberley coasts which originates from the Indian Ocean near to 20°S bringing possible showers to the northwest. The trough over eastern Australia is expected to move only slowly through Sunday, and, with the high ridging along the east coast, will keep much of the coast and near-coastal regions shower affected. The next 'pattern change' is likely to be early in the week with the baric ridge re-establishing a more northerly location nearer to 30°S than 45°S. This will once again allow low pressure systems and associated troughs and fronts become more west-east mobile as well as to affect southern Australia to a greater degree. Rainfall potential Victoria: Drizzle patches, particularly in the east, clearing. Morning fogs. A mostly fine day. NSW: Showers along the coast and inland areas, mainly in the north. Isolated storms in the northeast. Cold nights in the south with fogs & frost over higher parts. Queensland: Isolated showers in the southeast. Isolated showers over the tip of Cape York. Scattered showers along the rest of the east coast. NT: Scattered showers, mainly in the northwest. WA: Isolated showers along the coast between the Pilbara & Kimberley. Isolated storms possible. Drizzle along the south coast. SA: Isolated showers developing in the south and southeast. Morning fogs. Tasmania: Showers in the south and east clearing.
25	Clyve Herbert	It's interesting to see a persistent arm of the ITCZ running eastward from New Guinea half way across the south Pacific between 10 south and 15 south and so late in the season for the southern hemisphere, also a small disturbance just east of New Guinea (near 10 south) has developed some upper outflow features although surface convergence appears rather limited.
25	.	Overview: The slow moving high is located southwest of Tasmania and ridges strongly through the Tasman Sea and to the northeast with a secondary ridge along the east coast. This coastal ridge cradles a surface trough over northern Queensland (is this May?). Mid and upper level troughing over New South Wales is sagging slowly southwards after a couple of twirls since coming ashore near the head of the Bight a few days ago. The southeast of the continent is under a deep easterly flow (surface to ~300hPa / 30,000'), keeping moisture levels up & giving rise to scattered cumulus along the Victorian ranges. A front is crossing southern parts of Western Australia with a high approaching the west. Isolated storms have been reported in north central Queensland. Discussion: The high near to Tasmania is expected to remain quasi-stationary through Saturday, before beginning to weaken as it shifts east. The troughs (at all levels) look likely to sag southwards a little during Saturday while generally moving east. The south-north pressure gradient across the continent remains slack, and the trades are uncharacteristically weak over northern parts of Australia. High cloud crossing the Pilbara coast with the strengthening jet is not likely to trigger showers. A wave low may develop on the front passing through the Bight on Saturday and will be steered to the southeast around the high. Potential risk: An area of strong convection has developed near the Solomon Islands and is currently improving its organisation. This area should be monitored through the weekend. Rainfall potential Victoria: Isolated showers in the far east, with drizzle patches along the south coast in the morning. Widespread fogs with frosts in higher parts. A mainly fine day with a chance of isolated showers in the north of the state (if the trough sags far enough south). NSW: Scattered showers on the coast mainly in the south. patchy rain through inland areas with isolated storms, moving east. Queensland: Scattered showers and isolated storms, mainly in the northeast and southcentral and southeast corner, associated with the eastward movement of the trough. isolated showers over the northern tip of Cape York. NT: Isolated showers over the north coast, mainly in the west. WA: Drizzle along the south coast behind the front. Only isolated showers from the cloud crossing the Pilbara. SA: Scattered showers developing later, only light in the west. Morning fogs mainly in the southeast. Tasmania: Scattered showers in the west and south, clearing through Saturday.
24	.	Overview: The low over New Zealand is moving east, while the high in the Bight to the southwest of Tasmania ridges through the eastern states, cradles the surface trough which has wandered about South Australia, and ridges also through Western Australia. A trough and frontal system is crossing Western Australia. Discussion: The upper disturbance looks to persist over Australia for the next few days, cradled by the slow moving high currently to the southwest of Tasmania, and moving only slowly east. It is showing signs of possible deepening as it moves towards the New South Wales coast. Widespread patchy rain is likely to develop over the northern inland of New South Wales and southern Queensland under the influence of this trough. The pressure gradient (from south to north) over the continent is very slack for this time of year, with a highly zonal jet stream extending across the continent. The front moving through southern Western Australia will trigger showers along the south coast, while a baroclinic cloud leaf should be watched over the west for signs of vorticity, mainly in the mid and upper levels, which may trigger scattered showers. Rainfall potential Victoria: Isolated showers and drizzle patches in the south. mainly fine north of the ranges, except for an isolated shower near the Murray. NSW: Scattered showers through the inland with possible storms associated with the trough moving in from the west. Showers along the coast in a moist onshore flow. Queensland: Scattered showers developing with possible storms mainly in southern and south central parts of the state. Isolated showers over the tip of Cape York. NT: Isolated showers along the Top End coast, mainly in the west, with isolated showers in the far south. WA: Showers in the south associated with the passage of the front. Isolated showers in the Pilbara. SA: Showers in the northeast with isolated storms, becoming less frequent. Morning fogs, mainly in the southeast. Tasmania: Showers in the northeast becoming less frequent. Widespread fogs with highland frosts.
23	David Jones	This small scale upper low rotating around the very much larger upper trough (axis to the east of Tasmania) makes for a very interesting set-up. Also, the cold pool currently moving NE to the south of Western Australia looks like following the SA cold pool, in again rotating around the much larger upper trough (on the weekend). I am quite certain that much of New South Wales will see a two staged major rain event out of this, first in association with the SA upper low, and then the second upper low early next week. For us further south, the big unknown is whether the quite general upper trough is going to amplify through the next seven days (as suggested by the GASP model, for example), and see a developing easterly dip trough and then low intrude into northern Victoria. If this later event happen, we could well see a system like that of April 2001.
23	Clyve Herbert	A quick glance at the Australian synoptic chart today and you may be tricked into thinking it was summer not late May, also the pressure gradient over most of the continent is one of the weakest I have seen for awhile hardly any isobars sorry hectopasklebars, although all or most of the activity is in the upper layers across SA and western NSW.
23	.	Overview: The large low in the Tasman Sea has moved to the northeast but still affects a large section of our part of the globe - from New Zealand to Tasmania. A middle level low with an associated surface low has remained over southern parts of South Australia and has been moving only gradually northeast, cradled by the surface high that has cut it off from the westerly flow. This high also extends a ridge northeast through western Victoria and western New South Wales. A weak area of upper vorticity is located west of Tasmania and is moving slowly northwest. Moist infeed can be traced back to the trough off the Western Australian coast. The upper flow over Australia is strongly zonal with the jet at 300hPa (~30,000') stretching from north of Geraldton to near Brisbane. Discussion: The Tasman low will move eastwards to affect New Zealand tomorrow, mainly the South Island with heavy rain along the west coast and alps. The high in the Bight will strengthen as it moves steadily east to be southwest of Tasmania and the ridge to the northeast will moves through Victoria and New South Wales during Thursday, while the ridge to the northwest will move into western South Australia. The surface low over South Australia, initially moving southeast looks to weaken out to a trough at the surface during Thursday and may then be steered northeast, mirroring the movement of the associated lows in the upper levels. The next long wave trough will approach Western Australia during Thursday, strengthening northerly winds over that state & bringing increasing temperatures before the arrival of the next front later Thursday or early Friday. Potential risks: An area of vorticity is apparent in the upper levels west of Tasmania . This appears to be a westward extension of the cloud area that came around and grabbed onto the east coast of Tasmania today. This area is being pushed north by an upper ridge - will be interesting to see if & how it interacts with the upper moisture presently over the Bight. Rainfall potential Victoria: Drizzle patches along the coast, clearing. NSW: Isolated showers on the far south coast. mainly fine elsewhere after morning fogs with frosts over higher ground. The trough may affect northern New South Wales bringing some showers. Queensland: Isolated showers in the far southwest spreading east through Thursday, and the tip of Cape York. Mainly fine elsewhere. NT: Isolated showers in the south associated with the trough. WA: Isolated showers along the south coast, becoming more frequent in the southwest corner as the front enters the state late Thursday/early Friday. Isolated showers in the Pilbara. SA: Isolated showers associated with the upper lows and surface trough, with possible storms through the centre of the state. Fine elsewhere after early morning fogs, especially in the southeast. Tasmania: Showers in the southeast, becoming less frequent through Thursday. Widespread morning fogs.
22	.	Overview: The large low which has taken up residence in the southern Tasman Sea moved SW during Tuesday and deepened. Southwesterly winds affect much of eastern Australia.The high in the Bight strengthened and ridged under the low developing in the northern Bight near to Esperance. A broad trough extends from the northern Bight and runs to the northwest preceded by a ridge through eastern parts of South Australia and western Victoria. The mid level low is now over South Australia near to Ceduna and has dragged moisture in from the Indian Ocean and then southward. A weak upper ridge is approaching Western Australia. Discussion: The low in the Tasman Sea will weaken through Wednesday and move only slowly northeast. Eastern parts of Tasmania, Victoria and southern New South Wales will still be affected by its circulation with showers continuing in the southwesterly flow. This deep southwesterly flow will also bring 'cool pools' north from the Southern Ocean which are likely to interact with the mid level low moving through South Australia during Wednesday, triggering widespread showers. The high in the Bight will keep the area of low pressure close to the continent by halting its southeasterly movement, and may nudge it northeast. Upper temperatures over southern Australia will continue to rise slowly from the extremes experienced over the weekend, but are unlikely to rise to the levels before last weekend in the short term. Surface temperatures over southern Australia will also remain seasonably low. Rainfall potential Victoria: Scattered showers, mainly in the south and far east. Morning fogs inland and away from the coast. Cloud increasing in the west, with only isolated showers developing. NSW: Scattered showers on the south coast and Alps, falling as snow on the higher peaks. Frosts along the ranges. Mild to warm in the north. Queensland: Cloud increasing in the southwest, with scattered showers developing. Mainly fine throughout the rest of the state except the northern tip of Cape York. Cold nights inland with frosts likely. NT: Isolated showers are possible in the far northeast. Scattered showers developing in the southwest corner. WA: Showers in the southeast with isolated showers in the Pilbara. Drizzle patches in the southwest. SA: Increasing cloud with scattered showers mainly in the south, becoming more frequent with possible storms developing later. Tasmania: Showers developing in the southeast & becoming more widespread through the east. Clearing later Wednesday. Fogs and frost in central and northern area.
21	.	Overview: A complex area of low pressure is located in the southern Tasman Sea with a satellite low over West Gippsland. Another area of vorticity lies just west of Tasmania. A trough can be traced from western Queensland through the Coral Sea & through New Zealand to the low in the Tasman Sea. The high in the Bight, which has ridged southeast to cut the Tasman low off, is sandwiched between this large area of low pressure to its east and the following low just south of Western Australia with the next high entering the south of the state. A trough through the Gascoyne and the Goldfields is feeding a significant amount of subtropical moisture in ahead of the front. Discussion: The low in the Tasman will deepen through Tuesday with one main centre becoming defined and may move only slowly. The high to the west will slow and ridge to the southeast and cradle the low moving through the Bight, while a smaller cell of high pressure may bud off to the northeast of South Australia. Much of the north of the country will be fine with cold nights inland and possible frosts to fairly low latitudes. The long wave trough approaching Western Australia looks to strengthen, with upper flow becoming more meridional. There are signs of increasing vorticity in this area in the upper levels and the baroclinic cloud leaf over southern Western Australia should be monitored for development during Tuesday. Rainfall potential Victoria: Showers, in southern and mountain areas becoming less frequent through Tuesday. Fogs in the south. NSW: Scattered showers in the southeast, falling as snow on the Alps. Queensland: Mainly fine, except for drizzle in the south. NT: Mainly fine. WA: Showers in the south with isolated storms through the Gascoyne & Goldfields area, extending east to the Eucla through Tuesday. Fine in the north. SA: Showers in the southeast. Increasing cloud in the west with possible light showers developing. Tasmania: Showers, tending to periods of rain in the south and east with the influence of a passing by of a 'satellite low' to the east of the state.
20	Clyve Herbert	Interesting almost "local scale" low just off the northwest coast of Tasmania this morning, appears to be reacting to a small cold pool extension of the overall larger cold pool affecting southeast Aus. This area of vorticity can be traced to a cloud splotch that seems to have circulated around the primary low just east of Tasmania. At one stage this morning the 2300z sat pic showed an almost enclosed central 'eye'! just on the northwest tip of Tasmania. This small system is moving northeast
20	.	Overview: A complex area of low pressure developed over southeastern Australia during Saturday night / Sunday and has moved gradually east, while at the same time a cold pool in the middle levels over the southeast of South Australia this morning has moved northeast. Two returning cloudbands are moving in from the Tasman Sea, one making landfall across southern Victoria and another coming up west of Tasmania. Snow has fallen during the afternoon on higher parts of the Great Dividing Range from northeast Victoria as far north as the Central Tablelands of New South Wales . South Australia has also been affected by the southwesterly flow with scattered showers with hail in the southeast. Temperatures in the upper levels dropped considerably during the weekend, and only slight daytime heating has led to enhanced convective showers. A trough remains over the Indian Ocean feeding moisture across the West Australian coast, but a midlevel ridge and surface high has kept the west of the continent mainly fine except in the Pilbara where a midlevel cloudband associated with a trough has triggered showers. Discussion: Cool temperatures over southeastern Australia will prevail during much of this week. The low will move only slowly through the Tasman Sea and continue to direct southwesterly winds across much of southeastern Australia with widespread showers with some heavy falls. The high to the west will weaken, and will ridge to the northeast and southeast of this low. The far northeast Queensland coast may see some shower activity but most of central and northern Queensland will remain dry as will the Northern Territory. Nighttime temperatures over the north of the continent may be low enough to see frost in some inland areas. The southeast corner of Queensland may see some showers in the southwesterly flow. The next upper trough is already close to Western Australia and looks set to affect the southeast by midweek. Potential risks: There is a risk that the low in the Tasman may become cutoff during the next 24 hours. Rainfall potential Victoria: Widespread showers with periods of rain south of the ranges. Isolated storms. Snow likely to fall on higher peaks. Cold southwesterly flow. NSW: Showers in the south & central parts of the state, falling as snow on the higher parts of the Southern & Central Tablelands. Isolated storms. Mostly fine in the far northeast except for isolated showers possible later. Queensland: Isolated showers or drizzle patches are possible in the southeast and far northeast coast. Fine elsewhere with cold nights. NT: Mainly fine except for isolated showers along the northeast coast. WA: Showers in the southwest corner extending along the west coast as the front approaches, mainly fine in the north. Isolated showers possible in the Pilbara. SA: Showers in the south, more frequent in the southeast. Tasmania: Showers in the west and northeast becoming widespread through the central and south during Monday. Snow over higher parts.
		Images of the complex low pressure system over the southeast
19 (11am)	Clyve Herbert	It seems the vorticity max (VM) is located in the vicinity of Mt Gambier or in the southeast of SA area (upper VM). The former cold frontal cloud band is starting to wrap around this VM area worth keeping an eye on this set up over the next 6 hours.
18-19	.	Overview: The surface low pressure system associated with a deepening upper low, which passed across the southeast of the country during Thursday and earlier today is now located over the southern Tasman Sea, and has been replaced over land by a high which is being forced northeast across South Australia by the low pressure system in the Bight. This low has begun interacting with moist infeed from the Indian Ocean. The next high in this week's quick progression is approaching Western Australia. The trough from ex-TC Errol lies across the Pilbara coast and marks a developing mid level low just off the coast, as well as a strong jet in the upper levels. Discussion: A weak upper ridge will move through South Australia and Victoria during Friday night and early Saturday. The broad upper trough following through the Bight will deepen and increase its north-south amplitude - while signs of vorticity in the cold pool in the Bight are already apparent on Friday night and this system is steered northeast by the strengthening upper flow. The surface high affecting Western Australia during Saturday will strengthen a ridge to the southeast as well as the northeast, steering the deepening low towards the southeast South Australia / Victoria coast. Temperatures will decrease across the southeast corner as a deep southwesterly flow becomes established. In contrast to the activity in the south of the country, northern parts will remain mainly fine under the influence of an upper high. Temperatures through the north are also generally beginning to decline as seasonal heating decreases, and this is also seen in decreasing temperatures in the middle levels. Widespread frosts are possible. Potential risks: Widespread showers, some locally heavy, hail, snow at higher levels, are likely in the deep southwesterly flow establishing throughout the southeastern states later in the weekend. Keep an eye on areas having a deep cold SW flow across warmer waters, especially along the Victorian coast on Sunday. Rainfall potential Victoria: Widespread showers extending from the southwest later Saturday, with the chance of hail south of the ranges & snow over the Alps, extending down to ~1,000 metres at times, mainly during Sunday. Chance of storms. NSW: Showers extending from the west during Saturday, mainly in southern and central areas, with snow showers possible along the ranges as far north as the Central Tablelands at times later in the weekend. Hail at lower levels is possible in the south. Isolated storms. Remaining mainly fine in the northeast corner till later in the weekend. Queensland: Fine throughout. Cold nights. NT: Fine. WA: Scattered showers through the Pilbara & Gascoyne extending southeast through the Goldfields to the Eucla. Drizzle patches along the south coast. SA: Isolated showers in the west, becoming scattered in the south of the state, local hail in the southeast likely with isolated storms associated with the passage of the front & the establishment of a southwesterly flow. Tasmania: Showers in the west and the south early Saturday, clearing temporarily. Showers extending through to central parts Sunday, with hail & snow also likely over higher parts Sunday.
17	.	Overview: A complex area of low pressure is currently located over southeastern Australia. A longwave trough at the 300hPa level (~30,000'), and thermal troughing between 850 and 500hPa (~5,000 - 18,500') are also located over the southeast. Showers, hail, isolated storms & snow at higher levels have featured this afternoon. A trough extends from the southeast to Queensland through New South Wales and triggered storms in Sydney during the afternoon. The baric ridge has shifted slightly south today to lie through southern Western Australia and the northern Bight, before being interrupted by the complex low pressure area. Upper outflow from the convective area in the Indian Ocean (ex TC Errol) continues to feed moisture southeast along a trough across the Western Australian coast, and is then transported eastwards by the strengthening jet. Discussion: The complex low pressure area over the southeast corner will track eastward into the Tasman Sea, and will be followed by a colder air stream which will become generally established over the area. Snow showers over the Alps are possible, with lower elevations having scattered showers following in the southwesterly flow. The trough through northern New South Wales and southern Queensland will move off the coast early Friday, and the outlook for Queensland, Northern Territory and the northern part of Western Australia is generally fine. Showers will continue to be triggered by the moist inflow across the Pilbara coast, extending inland at times along the trough. The front which will cross the southwest of Western Australia during Friday, will intensify shower activity along the coast. Increasing cloud with strengthening NW winds in western parts of South Australia will precede this front which should cross that state later Friday / Saturday. Rainfall potential Victoria: Showers, heavy at times, mainly south of the ranges. Snow showers on the Alps, becoming isolated. NSW: Showers, mainly in the south, with isolated storms, moving off the coast. Snow showers over the Alps, becoming scattered during Friday. Becoming fine in the west of the state as a high approaches. Queensland: Fine throughout except the northern tip of Cape York. NT: Mostly fine, with only isolated showers along the north and east coasts in the morning. WA: Showers through the Pilbara and Gascoyne, extending inland and to the far southeast of the state. Drizzle patches and isolated showers in the southwest. SA: Scattered showers in the south, more frequent in the west with the approach of the next frontal system later Friday. Tasmania: Showers throughout, becoming more frequent and general through Friday.
16	Clyve Herbert	With all the excitement over south-eastern Aus this afternoon lets not forget former TC Errol which just keeps hanging on to life, although appears to be some sought of hybrid extra tropical low this evening northwest of Exmouth. It's being sheared by the sub tropical jet which has dragged some of the moisture all the way to the central QLD coast. It's not often you see such a system like this in May especially with such cold tops at this location - it will be interesting to see if it manages to keep itself together as it approaches the coast, another interesting feature are the very cold tops being generated above the main surface convergence region.
16	.	Overview: The high in the southern Tasman Sea has remained slow moving through Wednesday, and has helped to slow the eastward movement of the trough over South Australia, which has deepened progressively through the day. Moist infeed in the middle & upper levels from the Indian Ocean ~25°S as well as from ex TC Errol can be traced across Western Australia and into the broad area of low pressure currently over southeastern Australia. The low that was TC Errol, is moving southeast north of a ridge building through southern Western Australia. An interesting feature is the line of high cloud extending across Cape York to Timor. Discussion: An upper longwave trough to the south of the Bight will direct cooler air in the middle levels across southern Australia during the next few days. This broad trough will move in to replace the upper ridge that has influenced the weather in southeastern Australia during the last few weeks. With vorticity within the baroclinic area located in the eastern Bight, it seems likely that a surface low will form just west of Tasmania, while an associated middle level trough will deepen, possibly as far north as near the coast between Kangaroo Island and Mt Gambier. While the baric ridge is likely to remain at ~ 30 - 33°S over the west of the continent and dipping to be ~37°S over the Tasman Sea, it will help steer this complex southeast towards the southern Tasman Sea. Meanwhile, most of northern Australia will be fine under the influence of a large upper high while a mid-level trough near the coast of Western Australia is likely to develop & intensify shower activity in the Gascoyne & Pilbara. Rainfall potential Victoria: Rain areas extending east during Wednesday night and Thursday, with showers becoming scattered in the west and south of the ranges behind the front. isolated storms are possible. NSW: Showers developing in the west, and extending east through Thursday, most likely in the south. Isolated storms possible near the front. Queensland: Showers over the tip of Cape York. Mainly fine elsewhere with cloud moving into the southwest. NT: Isolated showers along the Top End coast. WA: Widespread middle level showers and isolated storms associated with the cloudband and developing trough over much of the western and southern parts of the state. SA: Middle level showers in the west, extending further east. Widespread showers in the southeast, clearing through Thursday. Cooler with isolated showers in the south behind the front(s). Tasmania: Widespread showers in the west and north, with local heavy falls, extending throughout.
15	.	Discussion: The high has progressed to be east of Tasmania while the middle level trough over the southern part of Western Australia has been caught by the front associated with the low that has been steered southeast through the Bight. Ex - TC Errol has disintegrated and clusters of convection are now approaching NW Cape. A middle level trough off the coast of New South Wales, sheared away from the front which has now progressed to New Zealand, has triggered showers with isolated storms along the central & north coast during the afternoon. Future Developments: The trough near the head of the Bight is showing signs of vorticity and is likely to develop into a low during early Wednesday and move southeast, steered by the slow moving high in the Tasman Sea. Moist infeed to the trough lying through South Australia and Western Australia will trigger widespread showers with isolated storms through much of South Australia, Victoria and Tasmania during Wednesday and Thursday. This infeed, part of which originates from ex - TC Errol will split, with the northern part of the band heading east through Western Australia north of ~23°S, triggering showers in the Pilbara. A high is approaching SW Western Australia. During Tuesday night and Wednesday, much of coastal New South Wales will remain under the influence of the middle level trough off the coast, which will remain slow moving and continue to trigger showers & isolated storms with occasional heavy falls. Rainfall potential Victoria: Increasing cloud in the west. Showers with isolated storms developing and extending east. Areas of patchy rain at times, mainly in the west and central districts. NSW: Showers along much of the central and north coasts and to the adjacent ranges, with occasional storms & possible heavy falls. Queensland: Isolated showers are possible in the far southeast corner & the top of Cape York. NT: Isolated showers along the Top End coast. WA: Showers with isolated storms along the central west coast and parts of the SW Land Division, moving east, with drizzle on the SW coast. Only isolated showers are possible in the Pilbara, mainly along the coast. SA: Widespread showers, mainly light with occasional storms, mainly in the south, extending east to the Victorian border later in the day. Tasmania: Increasing cloud during Wednesday but remaining mainly dry except for drizzle patches in the north & east. Showers tending to rain periods, mainly in the west & north during Thursday.
14	Clyve Herbert	Over the past two weeks some of you may have noticed the 'mirror' phenomena between the tropical regions of the northern and southern hemisphere...first was the twin TC's over the western Indian Ocean,then the twin tropical lows near to Indonesia's west coast one of which became TC Errol and now there seems to be a another possible twin development east of New Guinea over the northern and southern hemisphere about 5n and 5s. This area has become convectively positive over the past several days and appears connected to the Julian/Madden equatorial wave process. Visible image http://home.cfl.rr.com/tcrist/images/Twin_twins.jpg Infrared image http://home.cfl.rr.com/tcrist/images/MJO.jpg
14	.	Discussion: A slow moving high is located in the eastern Bight, while a front moves along the New South Wales coast and a middle level trough extends through to South Australia with scattered showers along its length. The new baroclinic cloud streak entering Western Australia is aligned along the north-south temperature gradient in the mid levels and also identifies the position of a strengthening upper jet. A surface low and frontal system is approaching the southwest coast. TC Errol has maintained intensity and has moved only very slowly WSW during the last day or two. A fresh surge of moisture from Errol has reached the West Australian coast at ~26°S. Future Developments: During Tuesday, the high will move only slowly east into the Tasman Sea, while the low approaching Western Australia will weaken & leave a trough through the southern part of the state. Moist infeed to this area from the tropical Indian Ocean may trigger showers with an isolated storm possible in the south. The cutoff low in the Coral Sea is wrapping a cloudband across the North Island of New Zealand and is likely to produce some substantial totals. A weak surge southwards from the tropics may be enough to trigger showers along the Top End coast & Cape York while the rest of the northern part of the continent will remain dry. The temperatures in the middle levels (850hPa - 500hPa) are beginning to drop gradually across our longitudes in the south, while moisture levels are steadily building in the same areas. Rainfall potential Victoria: Drizzle along the coast in the morning, clearing. Showers in the northeast, clearing. Morning fogs, mainly south of the ranges. NSW: Showers, mainly along the coast & ranges, extending north. Patchy rain in inland areas is possible with the cloudband. Queensland: Isolated showers along the south coast with scattered showers over the northern parts of Cape York. NT: Isolated showers over the Top End coast. WA: Dry in the north, showers and isolated storms in the south near to the trough, extending east. SA: Warm with patchy could. Middle level showers mainly not reaching the ground in the far west. Tasmania: Scattered showers in the south & west. Fogs elsewhere.
13	.	Discussion: The baric ridge runs through New South Wales near Sydney, central South Australia and exits the west of the continent at ~30°S. The low in the Tasman is cut off & marks the location of the cold pool in the longwave trough. A trough / frontal system which has drawn much of its moisture from TC Errol south of Indonesia, is passing through the southeastern states, while a 'wave front' has developed in the westerly flow in the southern Bight. The low to the southwest of Western Australia marks the position of the approaching longwave trough. Future Developments: A new centre of high pressure is likely to form in the eastern Bight during Monday extending a ridge to the northwest, while the eastern trough & associated front will move through much of New South Wales during Monday. The trough associated with the front will destabilise conditions through central Queensland The low in the Tasman Sea will continue its northeasterly track into the Coral Sea. The low at ~42°S approaching from the west will be steered to the southeast by this high. This entire area is interesting and should be watched for the next day or two as the longwave trough has already begun to move eastwards faster in the south, while the northern portion of the trough has become more "negative longitudinal" and can still be identified near to 20°S off the coast of Western Australia. Definition: negative longitudinal = where the low pressure system is located at the southeast, with a trough or front extending from the low towards the northwest. Rainfall potential Victoria: Showers overnight Sunday clearing through much of the state Monday. Drizzle patches in the southwest & Gippsland coasts with local fogs elsewhere. NSW: Scattered showers, mainly on the south coast and adjacent ranges, spreading to the central coast during Monday. Showers in the southern inland are likely. Queensland: Coastal showers in the far northeast and central coasts. NT: Mainly fine with only isolated showers in the northeast. WA: Isolated showers in the southwest as well as the Pilbara, extending inland at times, generally moving east. SA: Mainly fine in the south with just the occasional shower along the coast. Scattered showers with the chance of a storm inland as the trough moves east. Tasmania: Showers in the southwest & west becoming confined to the coast.
11-12	.	Discussion:Friday night gives a snapshot in time of a dynamic setup! A small high over southeastern South Australia is following a wave low now located in the Tasman Sea associated with the upper longwave trough now to the east of Australia and a cold pool in the middle layers. To the west, a deep low is approaching southwest Western Australia, associated with the next longwave trough in the series! - this is the third in a row all of which have peaked in almost the same location, except that this one is slightly more northeast than the previous two. Future Developments: Saturday should see the low in the Tasman steered north with a ridge building to its south, which looks to have a chance of cutting it off from the westerly flow. The high over southeastern Australia looks like it might slow the eastward passage of the low near to Western Australia and steer it more to the southeast during the weekend. Isolated severe thunderstorms with winds reaching gale force at times are likely to be a feature of conditions over SW Western Australia tonight & early Saturday. A significant cold pool follows these fronts. The upper jet to the west, which can be traced by the cloud approaching Western Australia from the convective area over Java and south of Indonesia, looks to strengthen and we may see the development of yet another cloudband triggering showers in SE South Australia, Victoria and Tasmania later in the weekend. Rainfall potential Victoria: Strengthening NW winds during Saturday, with cloud increasing in the west and rain developing during Sunday. Widespread morning fogs Saturday. NSW: Showers along the coast, mainly in the north with a weak trough moving through the area. Cold nights inland with fogs & isolated highland frosts in the central & south. Cloud increasing during Sunday ahead of the next frontal system. Queensland: Isolated showers along the east coast, particularly in the north & becoming more frequent later in the weekend. NT: Isolated showers mainly in the northeast. WA: Showers & isolated storms, some possibly severe with strong winds in the southwest during Saturday. Isolated showers in the central west & Gascoyne. Shower activity diminishing during Sunday. SA: Strengthening NW winds with increasing middle level cloud. Mainly fine during Saturday with showers and isolated storms in the south associated with the front during Sunday.. Tasmania: Strengthening NW winds. Mainly fine Saturday with rain & isolated storms extending from the west later in the weekend.
10	.	Discussion: The high in the Tasman Sea has continued to weaken as it has moved east, with a ridge to another weak high over land at the head of the Bight. A front with associated pre-frontal trough is moving through eastern Australia triggering showers, rain periods with embedded heavier falls in Tasmania, Victoria and southern New South Wales, while a small wave low with associated front crosses Tasmania. An easterly flow has become established over northern Australia. Another in the series of deep lows in the Southern Ocean is passing south of Western Australia. An upper trough is still located over the eastern Coral Sea. Future Developments: The high in the Tasman will continue to move east as will the high in the Bight, which during Friday will move over land at ~35S and move steadily across the southern parts of New South Wales. Another satellite low with an associated front will affect southern parts of Western Australia later Friday or early Saturday steered by yet another longwave trough. Stable conditions will affect South Australia during Friday as well as all but the SW of Western Australia and the NE of the Northern Territory, while New South Wales and southern Queensland will see showers, rain periods and possible isolated embedded storms moving east through the day. Central and western parts of Queensland may also see some showers. Rainfall potential Victoria: Showers in the far northeast clearing. Fine after early morning fogs with drizzle in the south. NSW: Showers, and isolated storms moving northeast through the day & clearing in the south. Queensland: Isolated coastal showers, scattered showers likely in the southeast & central southern parts. NT: Isolated showers along the northeast coast. WA: Scattered showers in the southwest with isolated storms as the front passes. Fine elsewhere. SA: Fine after morning fogs. Tasmania: Showers with periods of rain in the southwest and west with isolated storms possible.
9	Clyve Herbert	Nice looking cloud band approaching Victoria showing weak vorticity just west of Tasmania, although the jet associated with this set is weakening there appears to be reasonable mid level moisture and a marked lifting area just ahead of the clearing edge. Two areas of interest, one just south of the Solomon Islands and another just off the Indonesian coast..... The area just south of the Solomons has some reasonable convective structure, this region has been convectively active for a few days and is sitting on the northeast flank of the far northern tip of a long wave trough, again it's the upper north-westerly shear that appears to be dominating so upper divergence is limited. The other area of activity is at about 100 east and near to 5 south just off the coast of Indonesia (north of the Cocos Islands), this locality has seen sustained and massive convection over the past week or two but is now showing organised convergence and a not too bad upper divergent field, this area has also been sitting at the top of a long wave trough west of WA.
9	.	Discussion: The high that has been located over eastern Australia for the past week has finally begun to move eastwards into the Tasman Sea, with the baric ridge running through central South Australia to another weaker high approaching NW Cape. The deep low in the Southern Ocean continues to move southeast, and in association with the longwave trough located to the west of Western Australia extends a strong zonal westerly flow at the surface as well as throughout the atmosphere to the tropopause. The upper level vorticity centre located just off the Queensland coast has remained anchored for the past 24 hours. Future Developments: The high will continue its eastward movement across the Tasman Sea during Thursday followed by a series of fronts crossing Victoria and Tasmania, which are now able to affect inland areas also as the high's influence weakens over the southeast corner of the continent. Another deep surface low and longwave trough in the Southern Ocean to the SW of Western Australia will continue the zonal flow with more fronts embedded in the westerly stream. Moisture from the tropics will continue feeding into the front moving through southern Australia, with Tasmania being likely to experience periods of rain & isolated storms as this cloudmass slides southeast across the state. The weak trough through inland Queensland may trigger very isolated showers. Pressure across Australia generally is beginning to decline. Potential risks: A low may develop west of Tasmania on Wednesday night and intensify conditions there as it moves southeast during Thursday. Rainfall potential Victoria: Showers extending to rain periods in t he southwest with isolated storms developing during Thursday. Fine in the far east to start. NSW: Isolated showers with a weak trough moving northeast. Moisture increasing across the state from the southwest. Isolated storms possible. Queensland: Showers with along the eastern coast. NT: Fine, except for very isolated showers along the northeast coast. WA: Showers in the southwest corner becoming less frequent. Scattered showers also likely in the southeast of the state with isolated storms. SA: Cloud increasing in the west. Middle level showers with a windshift moving across southern parts of the state during Wednesday night & Thursday. Tasmania: Showers in the northwest & west, extending to central areas. Isolated storms.
8	Clyve Herbert	It has been interesting to follow the progress of the low south of WA now approaching 'super low' status (949hpa), over the past 4 weeks or so a number of very deep lows have been occurring over the Southern Ocean, some as low as 936hpa. The low south of WA has generated a broad trough to the north and strengthened the sub tropical jet, this has resulted in a 'flash' appearance of a moderate sized jet baroclinic streak across the Aus Bight over the past 6 hours or so. This jet streak can be traced back (moisture Plume) to the large tropical cloud area off the Indonesian coast.
8	Clyve Herbert	Although this area of activity appears to be weakening, a weak vorticity area can be seen not far off shore of Brisbane, max vorticity is in the mid to upper levels (17,000 - 27,000). This large area of baroclinic upper level cloud is on the top end of a mid lat long wave trough which can be connected to a super low well southeast of NZ (936hpa two days ago). There is also a positive convective area near to the Solomon Islands on the northeast flank of this Coral Sea cloud mass, it's all very interesting. In regards to tropical cloud areas, a massive region of convection has been operating off the south west coast of Indonesia for the past few days some of which is starting to feed into another long wave trough over WA.
8	.	Discussion: The extremely slow moving high which has been located over the southeastern corner of the continent now extends across the Tasman Sea, while sending a ridge back to the northwest through South Australia. A 300hPa (~30,000') upper trough is located over eastern Queensland and northern New South Wales with an intensifying upper jet over the Coral Sea. A strengthening upper jet is also making landfall over Western Australia with a longwave trough to the southwest. Increasing moisture levels over Queensland and Western Australia are becoming apparent. An easterly flow has re-established over the Top End which is likely to end showers except in the northeast corner of the area. Future Developments: The high looks to strengthen somewhat in its western portion during Wednesday, and maintain its northwesterly ridge, effectively steering any fronts approaching from the west away from inland areas of southern Australia and around its south side. Southern parts of Western Australia will see showers triggered as fronts pass east. A stronger NW flow should set up over South Australia and Victoria tomorrow, once again threatening May maximum temperature records in those states as warm air mixing down to the surface from the middle levels assists. Coastal Queensland will feel the effects of coastal showers in the moist onshore flow, while the large area of cloud over the Coral Sea looks to shear to the southeast, but should be monitored for any 'unusual' movement. The weakening front which moved through Western Australia is sliding southeast & should affect Tasmania during Wednesday. Potential risks: An area of vorticity just off the Queensland coast should be watched for the next 12 - 18 hours. May maximum temperature records are likely to be challenged or broken in South Australia and Victoria, mainly in inland areas. Rainfall potential Victoria: Mainly fine after morning fogs. NSW: Mainly fine after morning fogs. Isolated showers about the northeast corner. Queensland: Showers with along the eastern coast and scattered afternoon showers over the interior associated with an upper trough. NT: Fine, except for very isolated showers along the northeast coast. WA: Showers in the southwest corner becoming more frequent with the passage of a front. Showers also likely in the northern parts of the SW Land Division, extending inland, as moisture levels build through Wednesday. SA: Cloud increasing in the west. Mainly fine and warm. Tasmania: Showers in the south & west, extending to central areas. Morning fogs in the northeast.
7	Clyve Herbert	A large baroclinic area over the Coral Sea is starting to show upper vorticity just off the tip of Fraser Island. There also seems to be an upper cold pool associated with this system which extends westward over central QLD - worth a watch on this wildcard.
7	.	Discussion: The high has weakened over the Bight and allowed the rather rapid eastward movement of the cloudband associated with the deep low near to Western Australia, to be located east of the head of the Bight by Monday night. The ridge to the northwest has helped steer the low away from the coast. The low deepened through Monday and moved to the southeast. Dry air has now wrapped in around the low. The cold air field associated with this low & longwave trough reaches as far north as the sub-tropics over the Indian Ocean (~20S). The southeast of the continent remains under the influence of the high, while in the north of Queensland, a moist NW flow from the tropics has generated scattered showers & isolated storms over the northeast tropical coast and the Coral Sea. Future Developments: The high will remain anchored over southeastern New South Wales (at the surface and in the middle levels) with a ridge extending to the northwest through South Australia and Western Australia. Showers associated with the tropical flow across northern Queensland looks likely to continue while extending southeast into the Coral Sea under the jet. Significantly colder air in the middle levels will cross the coast into Western Australia during the next 24 hours, and this may see some 'wintry showers' over parts of the SW Land Division. South Australia will see a windchange as the front progresses east, but it will slide away to the southeast and only affect coastal areas. Temperatures rising in the southeast during Tuesday. Potential risks: May maximum temperature records are likely to be challenged or broken in South Australia and Victoria, mainly in inland areas. Rainfall potential Victoria: Mainly fine after morning fogs. NSW: Mainly fine after morning fogs. Isolated showers about the northeast coast. Queensland: Showers with isolated storms along the northern tropical coast. Fine elsewhere. NT: Fine, except for very isolated showers along the northeast coast. WA: Showers on the west coast becoming less frequent, with a band of widespread showers and occasional storms moving through the southeast of the state during Tuesday. SA: Cloud increasing in the west. Mainly fine and warm. Tasmania: Showers in the south & west. Morning fogs in the northeast.
6	.	Discussion: Although weakening, the high has remained over the southeastern corner of the continent with multiple ridges extending along the east coast, through South Australia and the northern parts of Western Australia and more strongly through the Bight. A deep low, associated with another longwave trough is approaching the SW Land Division of Western Australia. A front is crossing Victoria and Tasmania Sunday night. Future Developments: The high will begin to edge slowly northeast while ridging more strongly to the southwest through Monday, but this is a temporary change as the baric ridge will weaken steadily through the week. This initial ridging on Monday may block the eastward movement of the low (a similar pattern to last week). This low looks most likely to deepen while moving southeast through the Bight. Tropical activity has virtually ceased over the north of the continent, and showers, if any, are now only very isolated. The thermal trough currently to the west of Australia over the Indian Ocean, extends as far north as 28 deg S, and may possibly bring significant temperature decreases to southern Western Australia. Large active storms are associated with this extensive area of cold air and severe storms are possible along the coast as the colder air moves over warm waters off the Western Australian coast. Potential risks: If the baric ridge shifts further north, the low may be able to maintain a more easterly track for the next day or so. Rainfall potential Victoria: Isolated drizzle in the south, fogs then mainly fine elsewhere. NSW: Isolated showers around the northeast corner, with morning fogs clearing to a fine day for most of the state. Queensland: Isolated showers along the coast. NT: The risk of isolated showers along the NE Top End coast. WA: Scattered showers with the risk of a thunderstorm associated with the passage of the front through southern regions. Fine in the north. SA: Fogs in the southeast, clearing. Tasmania: Scattered showers in the west and the south.
5	.	Discussion: The high off the south coast of New South Wales remains quasi-stationary, while the middle level 'cool pool' that was over the north of the state yesterday has moved southwards along the coast triggering heavy showers and hail. Ridges of high pressure remain along the coast as far north as the Queensland tropics, and through South Australia and around the head of the Bight. The low in the southern Bight is moving southeast, while the front approaches the South Australian coastline. Showers are triggered in the moist air over Western Australia. New Zealand sees a strong temperature gradient from the SW to the NW with associated strong winds. Future Developments: The high will remain over the southeast of the continent and be the dominant surface feature through the next few days. The middle level cool pool, should be watched during Sunday, as shower & thunderstorm activity may be triggered in its vicinity. Tropical showers are likely over Cape York in the moist northwest flow, and showers are again likely over the Queensland east coast, and extending as far south as northeast coast of New South Wales. The high is likely to build a ridge to the southwest through the Bight and continue the blocking of the approaching low currently southwest of Perth. The front moving through South Australia and Victoria during Sunday is likely to trigger only isolated showers. New South Wales may only see the very northern extension of this front in southern areas. Potential risks: the middle level cool pool near the New South Wales coast should be watched during Sunday. Isolated showers & the possibility of storms is likely to be associated with it. Rainfall potential Victoria: Morning fogs. Showers developing in the southwest. NSW: Showers along the coast, mainly in the north. Queensland: Scattered showers along the coast. isolated showers over Cape York. NT: Isolated showers over the Top End coast. WA: Isolated showers in the south, moving east through Sunday. Showers developing along the southern parts of the west coast later. SA: High cloud increasing but only isolated middle level showers likely. Tasmania: Scattered showers in the morning, mainly in the west and south, becoming less frequent.
4	.	Discussion: The high just off the southeast coast of New South Wales weakened through Friday as it edged offshore. Broad ridges extend northwards along the coast and through South Australia to the northwest. The front through Western Australia is slipping southeast through the Bight leaving a trough through the state, while another high ridges in from the Indian Ocean. An area of convection has developed over the Arafura Sea to the north of Darwin, while an upper trough through the Coral Sea contributes to increased cloud through northern Queensland. Future Developments: The high off the New South Wales coast will remain almost stationary through the period with the upper trough through western New South Wales, Victoria and Queensland edging slowly east into moister air. The surface high, combined with a strong upper ridge looks to ensure virtually unchanged conditions through Saturday over the eastern states. A 'cool pool' in the middle layers over northern New South Wales, may be trigger some isolated shower activity over the coast and on the ranges inland. Tropical inflow from the Indian Ocean continues to feed into the trough through Western Australia which may trigger showers in the Pilbara and inland, but further southeast, showers will become more isolated as the front and associated cloud moves into the Bight. The low looks to restrengthen as it moves southeast through the Bight. Rainfall potential Victoria: Morning fogs, then fine. NSW: Scattered showers along the coast, mainly central and north, with showers also over the northern inland associated with the 'cool pool' over the area. Queensland: Isolated showers, along the coast, more frequent over the central parts & the adjacent hinterland. Scattered showers possible in the southeast corner. NT: One or two showers possible over the northeast of the Top End. WA: Scattered showers and isolated thunderstorms through the south of the state, becoming less frequent as the front slides southeast. Isolated showers and storms in the Pilbara and adjacent inland areas with the trough. SA: Morning fogs in the southeast, then fine. Cloud increasing in the west. Tasmania: Morning fogs, clearing to fine, but with increasing cloud later.
3	.	Discussion: A quasi-stationary high is planted over the southeast corner of the continent ridging along the east coast to the tropics and to the northwest through the head of the Bight. This ridge has remained weak enough for the low approaching Western Australia to remain north of 40S. A strong front associated with this low is approaching the Western Australian coast. Bands of high cloud are located over the Queensland tropics as a moist northwesterly flow crosses Cape York from the New Guinea region. A weak upper trough is located over South Australia. Future Developments: The high will slowly move along the New South Wales coast during Friday and Saturday, while a strengthening ridge to the northwest will steer the low near to Western Australia southeast through the Bight. Strengthening winds are likely across Tasmania, especially in the south. The moist northwesterly flow over northern Australia looks likely to continue for the next while, but is unlikely to trigger more than isolated showers in the north. The upper trough over South Australia will move east into Queensland, New South Wales and Victoria during Friday and much of the weekend, but only very isolated activity can be expected except in the SE of Queensland, while a strong upper ridge will replace the trough over South Australia and become established during Friday. Potential risks: the cold pool SW of Perth may become detached from the front. Rainfall potential Victoria: Morning fogs, then fine in the east. NSW: Scattered showers along the coast, mainly central and north. Queensland: Isolated showers with the risk of a storm in the southwest, isolated showers Cape York and isolated showers along the coast. NT: One or two showers possible over the northeast of the Top End. WA: Widespread showers and isolated storms through the south of the state, becoming less frequent through Friday as the front slides southeast. SA: Morning fogs in the southeast, then fine. Tasmania: Isolated drizzle in the southwest, morning fogs & frosts elsewhere, clearing to fine.
2	.	Discussion: A dominant high is located just west of Tasmania and sends a broad ridge through the eastern states to the tropics of Queensland, while also ridging to the northwest through South Australia. A low (analysed from the surface to the 300hPa level - ~30,000'), is drawing moisture from the Indian Ocean south of Indonesia, while cold air from the Southern Ocean is beginning to wrap around it. Through Wednesday, this low has moved due east and the front is approaching the southwest Western Australian coast. Future Developments: The high is expected to remain slow moving in the southeast Australian region for the next few days, and a ridge through South Australia and northwest through Western Australia may steer the approaching low to the southeast, with the front slipping away and only affecting the SW coast of WA if this happens. Occasional showers are likely to linger over parts of Cape York and the Top End with the northwest flow bringing an increase in moisture levels. Most of the southeast of the continent will experience fine (no rain, but not necessarily no cloud) weather after morning fogs & occasional frosts in elevated regions for the next few days. Isolated showers are likely to persist along the northern New South Wales and Queensland coasts in the southeast onshore flow. Potential Risks: An area of strong convection north of Vanuatu has developed and is of interest. Rainfall potential Victoria: Morning fogs, clearing. NSW: Showers along the coast, mainly in the central and north. Fogs & isolated frosts clearing to a fine day. Queensland: Isolated showers along the east coast, mainly in the north & also over northern parts of Cape York. NT: Isolated showers over the Top End. WA: Widespread showers & scattered thunderstorms associated with the front in the SW Land Division and moving southeast. SA: Morning fogs, mainly in the southeast, clearing. Tasmania: Isolated drizzle patches in the southwest, fogs elsewhere with highland frosts. A fine day.
1	Clyve Herbert	We should all move to southwest WA over the next few days, nice cold frontal band with embedded storms moving southeast towards that region, looks like the area south of Perth appears to be favoured for some good falls of rain, plenty of moisture especially in the mid levels. The low to the west has an impressive cold pool associated with it at 500hpa and seems to have reached its farthest northerly location before wrapping around the maturing low today ,there's a slight chance of this cold pool becoming cut off over the next 24 hours especially if a strong ridge develops to the south.
1	.	Discussion: The high located just to the east of southern New South Wales in the Tasman Sea has strengthened westwards into the eastern Bight as well as extending a broad ridge along the east coast to the tropics. The trough lying through eastern Australia has moved west and weakened. The northern tropics are still affected by tropical moisture originating from a trough through the Arafura Sea, but only isolated shower activity along the coasts has occurred. The trough through southern Western Australia remains slow moving and a complex longwave trough with an associated extensive cold air field is approaching Australian latitudes centred at 40degS. Future Developments: The high will remain over the eastern Bight area, through Bass Strait into the Tasman Sea during Wednesday while strengthening westwards. The current setup looks like the resident large high may block the approaching low and steer it to the southeast, with only the SW of Western Australia feeling the effects. The middle level 'cool pool', which passed over Victoria on Tuesday will continue to move northeast during Wednesday, identified by the presence of upper cloud, but should remain inactive. Showers are likely to continue along much of the east coast in the onshore flow set up by the ridge. Scattered showers and isolated storms are likely to continue through southern Western Australia associated with the trough, while the northern parts of the state and the Northern Territory remain mostly dry with only very isolated showers likely. South Australia and Victoria will be dry and mild after early fogs, while SW parts of Tasmania may see drizzle patches in the wake of the front. Potential Risks: If the high currently residing in the Bight ridges to the southwest, there is a chance that the complex low approaching may be steered towards our coastline. Rainfall potential Victoria: Valley fogs, then fine. Possible drizzle along the coast overnight. NSW: Coastal showers, more frequent over the central and north coasts. Queensland: Isolated coastal showers, also over Cape York. NT: Isolated showers over the Top End. WA: Scattered showers and isolated storms associated with the trough in the south, SA: Fogs in the southeast, clearing to a fine day throughout. Tasmania: Drizzle clearing from the southwest. Fine elsewhere after fogs.
.	.	April Forecast Outlook, Discussion & Report page
.	.	Victorian Weather Glass