January 2001 Forecast Outlook, Discussion & Report Page

Victoria

Information

A high pressure area continues to persist along the baric ridge south of Victoria. A marked trough has affected eastern NSW and south-eastern QLD with widespread heavy storm - this trough is also supported by a strong upper trough between 500 and 250hpa.  A rather strong upper ridge extends from northern Victoria to eastern Northern Territory.  A marked field of upper divergence has moved seaward from north-western WA.  A mid latitude trough and cold front is moving towards the western Bight region. The split high pressure region west and east of Tasmania will combine into a single identity east of Tasmania later Friday and strengthen a ridge northward off the east coast of NSW and QLD - this effect will pressure force a surface trough westward into inland NSW and central QLD with the upper trough shearing eastward into the northern Tasman Sea, the upper ridge however will suppress activity along this trough for 24 to 48 hours. The trough over WA will combine with the mid latitude cold front moving through the Bight and move into south-eastern Australia on Saturday and Sunday but this system will weaken and stall over Victoria and NSW. The trough over WA will reform and persist. The upper ridge over eastern Australia will gradually weaken from Saturday. The high in the south Tasman Sea by Saturday will be slow moving and probably strengthen, while the baric ridge will be maintained running from south of WA to Tasmania.

TEMPERATURES.....A warming trend will affect inland Eastern Australia from Friday.  A brief milder phase will affect south-eastern SA and southern Victoria on Saturday and Sunday but the remainder of inland Victtoria and NSW will remain very warm to hot with very warm conditions persisting into next week.  Very warm air will again spread into southern Vic from Monday ahead of a cooler trend from next Wednesday. The trough over WA will see a persistence of high temperatures in most of that state. The eastern seaboard of NSW and QLD will experience moist warm northeast to southeast flow patterns.

RAINFALL.....Areas favoured for rainfall are the Top End of the Northern Territory and the Kimberley region -   some good falls are also likely over the Pilbara and a few storms even over the Goldfields region of WA.  A few afternoon storms should affect much of inland NSW and south east QLD through most of the outlook. Stream showers should also affect eastern coastal areas of NSW especially night and morning. The weak trough moving through south-eastern Australia later Saturday and then stalling on Sunday may produce a few showers and the odd storm.

RISKS.The large area of upper divergence moving seaward west of Broome is an area of risk potential for the development of a TC and should be watched over the next 24 to 72 hours. Moisture content over south-eastern Australia has increased markedly over the last 24 hours and this area should be watched for potentially heavier storms on Saturday and Sunday. The weakening of the upper ridge from Sunday over eastern Australia should see showers and storms return to northern QLD from Monday.

Regards from the team at the Geelong Weather Services Clyve Herbert and Lindsay Smail. (NMP)

A forecast top of 43 has to be close to the highest I have seen, although in Jan 1968 (maybe Blair can confirm) the forecast top was for 108F on the 30th or 31st? I recall a max in Geelong that day of about 110F, back to Sunday though there seems to be a build up of mid level cloud to the west of the state, there is an offchance this may cover parts of Vic tomorrow, although much of the hot air will be advected from clear skies over northern Vic and eastern SA.

Over the last hour or so the wind has turned NW at Dunns Hill, in the Dandenong's.  A corresponding rise in temperature occurred and the relative humidity plummeted, with DP's now in the negatives. Other stations near sea level have easterly winds and high relative humidity's.  A classic inversion is developing over Melbourne. The temp will continue to build on Dunns Hill overnight.

During tomorrow morning this inversion will break down and Melbourne's temp will rise from about 20 to well into the 30's in a matter of minutes. I'm tipping 44.2 for Melbourne tomorrow, that's if the cloud isn't too bad. That stuff out west is a bit of a worry, but I think the freshening NW wind ahead of the trough will break it up.

Hi all weather lovers.

A stalling trough over south-eastern Australia will persist over the weekend until this system becomes absorbed into an approaching mid latitude trough and cold frontal system which should approach the southeast of the continent on Sunday.  The surface trough over inland NSW and northern Victoria reflects the presence of a very warm airmass, although an upper ridge has suppressed shower and storm activity across Victoria this situation is now changing and the approaching mid latitude cold front and trough should see some major warm advection across the southern half of Australia during Saturday and Sunday. The same pre trough lower and middle level flow pattern should also progressively bring increasing moisture across south-eastern Australia especially later on Sunday.   An upper trough over and south of Victoria today Friday 12.01.01. has generated some light rain and plenty of mid level cloud - this area of cloud should drift eastward by Saturday.  The baric ridge will rebuild behind the mid latitude cold front from Saturday as this system moves across the Australian Bight with a new high developing over the northern Bight area on Sunday and then extending a ridge towards Tasmania by Monday. The north of Australia will see a continuation of activity associated with the ITCZ, and an area of divergence is still evident just north of the Kimberleys and this area should continue to be watched over the next two days. The passage of the cold front across south-eastern Australia on Sunday should also see the northern portion stalling over northern NSW and inland QLD on Monday.

TEMPERATURES.....Hot to very hot conditions will affect SA, inland NSW and northern Victoria on Saturday and extending to southern Victoria and Tasmania on Sunday. A moderate strength cool change will bring cooler air across southern SA Saturday and most of the southeast and Tasmania on Sunday and Monday.  A persistent heat trough over WA will maintain hot conditions there throughout the outlook period with the baric ridge being forced southward of that state and maintaining northeast to southeast flow patterns. The far north of NSW will also remain hot with little relief from the cold front passing across the southern states. QLD will remain very warm to hot throughout the forecast period and with higher humidity, conditions will be uncomfortable. The northern tropical regions will see seasonal very warm and humid conditions.

RAINFALL.....Areas favoured for significant rainfall over the next four days are the Top End of the Northern Territory, the Kimberley region,  also the Cape York peninsular region. Parts of central and southern QLD may also receive local heavy falls from storm activity.  Surface convergence over the top end of the NT is weaker than last week, however some falls may be sufficient to produce local flooding -   there is some risk of flooding over the north Kimberley region also. The passage of a trough and cold front across SA and the southeast of Australia may see some local moderate falls especially in Victoria on Sunday and Monday - there is also a risk of local heavy falls on Saturday and Sunday over northern Vic and inland NSW due to the risk of thunderstorms.

RISKS.....The area just north of the Kimberleys still shows some weak low level convergence and upper divergence and this area would be worth watching over the next two days.  Another area of interest is the slight risk of a low developing over south-eastern Australia later Sunday and Monday if this occurs rainfall will be heavier over Victoria.

Regards from the team at the Geelong Weather Services Clyve Herbert and Lindsay Smail. (NMP)

A strong high pressure area southeast of Victoria on Tuesday (09.01.01) is slow moving - the baric ridge extends towards the Australian Bight then to another high pressure cell well southwest of WA. This baric ridge is dissected by a weak trough extending southward from WA to the Southern Ocean.  Another interesting feature is a tropical low over the Top End of the Northern Territory - this system has rather well defined high level divergence and good low to mid level convergence. Over land this system will bring good rainfall to this region, however its structure shows that it may develop into a dangerous tropical cyclone if the area of low pressure moves over open sea especially if this occurs west of Darwin. The weak trough over WA will move steadily eastward to reach the southeast of Australia later Wednesday and Thursday and then become slow moving and stall over northern Victoria and inland NSW.  A new trough will develop over WA . The high cell southwest of WA will build along the baric ridge towards the Australian Bight with a new high showing up in that region from Thursday.

TEMPERATURES.....A marked warming trend is evident for south-eastern Australia with high temperatures over SA,Vic and most of inland NSW for Wednesday and Thursday, the passage of a weak trough through SA later Wednesday and the southeast of Australia on Thursday will bring milder conditions to coastal areas only with very warm to hot conditions persisting inland. Very warm to hot conditions will also prevail over much of WA. The remainder of tropical Australia will see seasonal warm to hot conditions, a rather strong ridge up the east coast of Australia will see persistent northeast to easterly flow patterns there with warm and humid conditions. The far Top End of the NT will experience slightly below average maximum temperatures over the next two days under the influence of the tropical low.

RAINFALL.....The Top End of the Northern Territory is very favoured for heavy to locally flood rains over the next two to three days - if this tropical low moves westward the rain influence may spread to the Kimberley region of WA. The trough now over eastern WA will migrate towards southeastern  Australia by Thursday, this system will be accompanied by scattered high based showers and some with thunder.  A small low pressure over the south of QLD will weaken as it moves eastward but convergence in that area may produce isolated heavy falls over the next two days.  With the trough over south-eastern Australia on Thursday,  this system appears to be stalling over northern Victoria and NSW on Friday and Saturday, there should be a marked increase in available moisture after Friday and this may lead to more significant storm activity on Friday and into the weekend for NSW and Victoria.

RISKS....Although a bit of a wild card there is a strong tropical disturbance over the central south Indian Ocean with a marked moisture plume extending towards WA and this should be watched for interaction with midlatitude frontal activity over the next several days, especially the far southwest of WA.

Many regards Clyve Herbert and Lindsay Smail. Geelong Weather Services .(NMP)

The marked activation of the ITCZ north of Darwin today (Thursday 4.01.01) will also aid in the strengthening of the baric ridge from a high pressure cell southwest of Perth to the Australian Bight region. This baric ridge will progressively over the next several days push to the south of Victoria and into the Tasman Sea by Sunday.  A weak thermal low over central Victoria on Thursday will dissipate and become absorbed into a stalling trough over north-eastern Victoria and eastern NSW. This trough will persist over inland NSW and north-eastern Victoria throughout the outlook period.  A marked ridge should persist just off the east coast of Australia - this ridge should be strengthened as a new high pressure cell develops in the Australian Bight area on Friday and then progresses along the baric ridge towards the Tasman Sea by Sunday.  A trough (heat) over WA will persist over the outlook period. Weak mid latitude cold fronts should skirt the southern areas of Tasmania.

TEMPERATURES......The western half of Australia (WA and northern and Western SA) will experience high temperatures with extreme heat developing over central WA especially from Saturday.   The north of Victoria and most of inland NSW and western QLD will remain very warm to hot - milder conditions will affect southern Victoria from Friday although it will remain rather warm inland away from the coast. Tasmania will see cool to mild conditions persisting.  Much of the east coast of NSW will remain warm and humid with moderate north-easterly winds.

RAINFALL.....Areas favoured for significant rainfall will be the Top End of the Northern Territory & the Kimberley region of WA.  Some locations within these regions may see locally very heavy falls over the next three days. Isolated moderate falls may also affect parts of inland WA along the persisting trough line with mid level activity sporadically spreading into SA.  A stalling trough over eastern Australia extending from western QLD to northern Victoria may generate scattered afternoon thunderstorms some of which may be heavy - a few storms may also spread from the dividing range of NSW onto the central coastal regions with isolated heavy totals possible.

RISKS....The rapid intensification of the ITCZ should be watched for localised convergence areas especially from Saturday to the north and west of Darwin.

Many regards Clyve Herbert and Lindsay Smail. Geelong Weather Services .(NMP)

Hello all weather watchers.

A slow moving high pressure centre west of Tasmania is the main feature affecting south-eastern Australia ( 29.12.00 ) - this high pressure cell will very slowly weaken over the next 3 days as it "amoebas" eastward just to the south of Tasmania and into the south Tasman Sea by later Saturday or Sunday.  A major trough should clear the eastern side of the continent overnight Friday and Saturday. The far northern portion of this trough however looks rather interesting and appears to be showing a tendency to stall over the far north of QLD on Saturday and Sunday, there is also some weak divergence at 300hpa to the north of this tropical disturbance - interestingly this area of tropical surface convergence has persisted for a number of days and originated from the remains of tropical cyclone Sam.

Elsewhere in Australia most of the interior is experiencing mainly fine conditions under the influence of a rather strong upper ridge extending from Victoria to the west of Alice Springs - this upper ridge also has rather dry air near the surface.  A trough moving through SA Saturday and Sunday is rather weak and should reach the southeast of Australia later Sunday and Monday and remain a slow moving feature during its journey.  A high pressure system in the south Indian Ocean extends a ridge to the southwest of WA -  this ridge should remain rather weak.  A small new high should bud off this ridge later Sunday or Monday to become centred in the Australian Bight area.

TEMPERATURES......The prolonged cold spell over south-eastern Australia is now coming to a close and a warmer trend is expected from Saturday with progressively increasing temperatures to at least next Tuesday.  Very cool conditions will linger in Tasmania to at least Sunday a few frosts can be expected over inland Tasmania Saturday and Sunday. The north of Australia will see above average temperatures for most of the outlook with hot conditions moving into SA on Saturday. The southwest of WA will remain mild until Saturday and then warm to hot conditions will redevelop from Sunday as a surface ridge builds to the south of that state. The east coast of Australia will experience mainly average temperatures with a warming trend from Sunday.

RAINFALL......The only areas showing indications for heavy rainfall is the east coast north of Cardwell and the Cape York Peninsula. Some very heavy falls are possible over these regions on Saturday and Sunday with the possibility of some flooding.   No significant falls appear likely for the remainder of Australia at this stage -   the trough over SA will only move slowly over the next three days and a few afternoon showers should develop near to the trough line, as this trough moves into south-eastern Australia later Sunday,  a better moisture supply should see showers and the odd storm develop over the mountain regions of Victoria and NSW with the risk of more general storms on Monday and Tuesday.  A heat trough should also persist over eastern QLD with a few storms over the southeast and central divide of that state. The upper ridge will suppress storm activity over the Top End of the Northern Territory and the Kimberley region on Saturday and Sunday but activity should become more frequent again by Monday.

RISKS.....The area of convergence over the Cape York area continues to be of interest and should be watched over the next 24 to 48 hours..

A VERY HAPPY NEW YEAR FROM THE TEAM AT GEELONG WEATHER SERVICES

Regards from Clyve Herbert and Lindsay Smail.....(NMP)