NATIONAL WEATHER PICTURE - PM EDITION - MONDAY MAY 31ST 2021.

Headlines


  • Showers and strong winds continue along the southern WA coast this evening.

  • High cloud over the east heralds the chance of rainfall increasing mid week.

  • Another frosty night on the cards for southeast areas.

  • Possibly some rainfall returning to the Pilbara later this week.

Showers and strong gusty southerly winds continue for southern WA today, with areas of rain over parts of the SA/WA border this evening. Light falls for the most part along the border, but the heavier falls have been confined to the wrap around rainfall on the western side of low pressure near Esperance. Showers have cleared from the west coast, but it is cool in southerly winds. Some rain is linger over the Pilbara and adjacent inland this evening along the jet stream.


It has been a day of clear weather and loads of sunshine over QLD, NSW and VIC, however the cloud has started to build on the western horizon in all of these states, with a cloud band filtering through the east ahead of a trough moving over eastern WA. The cloud is fair weather, but may also assist in bringing up minima overnight after record cold observed in some locations through the east.


Yet another frosty night is on the cards tonight for the east and the morning could see some more record cold temperatures observed over parts of SE NSW and the ACT. The string of cold nights since Saturday could be the coldest spell of weather on record for this region this early in a season ever! That is quite remarkable given the absence of really bitterly cold air behind a cold front.


The moisture over the Indian Ocean continues to oscillate through the basin with some of the moisture being drawn into the jet stream as it bends and flows throughout the subtropics. This will propel some rain periods to the coast of the Pilbara and Gascoyne later this week.


National Satellite Picture - Monday 31st May 2021.

Cloud fanning throughout SA is mainly fair weather with no rainfall, as the moisture becomes compromised with the copious dry air in place and stable atmosphere. A rain band is in place over the WA/SA border with mainly light falls under that middle level cloud. A low is continuing to move east along the south coast of WA with scattered showers and local hail with squally winds. Elsewhere, low cloud in the east of the nation is contracting offshore. Some cloud and light showers over the eastern parts of QLD and NT. Moisture offshore the northwest is continuing to produce areas of mainly light rainfall about the Pilbara but some of that could become heavier tonight.

Low pressure rotating along the south coast is producing widespread showers with local hail and thunder. Gusty winds continue for coastal areas, but it is slowly contracting east. Rain has broken out in the warmer sector over the SA/WA border with light falls for the most part. This low will begin to weaken a tad through Tuesday with the rainfall coverage easing.

Rainfall has been heavy overnight for the SWLD with around 50-70mm additional rainfall falling along the coastline in that gusty southerly wind regime. On Monday the rainfall has nearly ended for most areas, just isolated showers and drizzle in overcast skies continuing for areas west of Albany.


Rainfall observed in the 24hrs to 9am Monday 31st of May 2021

Rainfall has continued east of Albany on Monday with some moderate falls being observed in some locations on Monday morning. A few locations could see 30-60mm over the coming 24 hours as the low moves east along the coast. Light rainfall is ongoing over the Eucla this morning with a rain band forming in the warmer sector.


Rainfall observed since 9am - Monday 31st of May 2021.

Temperatures this afternoon have recovered nicely over parts of the southeast after a record cold start for a number of sites. Brilliant sunshine making it feel pretty good at lunchtime. In the west more cloud and showers keeping the south coast cool. Fairly seasonal elsewhere, though running below average over the west and northwest with cloudy skies and light rain about the Pilbara.


Temperatures as of 2pm EST - Monday May 31st 2021.

A nice warm up over the southeast after that record cold start.

Note the temperatures of 20C over the Ceduna region, that warmer air will filter eastwards on Tuesday for NSW and VIC.

Rainfall for the coming 10 days is very tricky to forecast with upper lows in place making things very tricky to pin down.


Overall there will be rainfall developing from SA through southern QLD, NSW and into northern VIC from mid week with some moderate to heavy falls in pockets in these states, especially in northern NSW and QLD. The rain will be falling mainly from Wednesday through Thursday and will clear Friday.


Another system next week has the potential to double rainfall for parts of the east and southeast with a major upper low being drawn in on some charts, but it is a low confidence forecast beyond Sunday.


Rainfall for the next 10 days - Valid Monday May 31st 2021.

LOW CONFIDENCE FORECAST APPLIES FOR THIS CHART.

Severe frosts are likely once again for the southeast inland of Australia with a freeze possible over the ACT and adjacent areas north and south along the GDR as we track through Monday Night into Tuesday.


Rainfall for the next 10 days - GFS 00z run - Valid Monday May 31st 2021.

CMC 00z run Rainfall for the next 10 days - Valid Monday May 31st 2021.



Frost Risk Forecast - Tuesday 1st June 2021

Freeze Risk Forecast - Tuesday June 1st 2021.



Model Analysis


An upper low is expected to move eastwards across the southern parts of the country with a trough associated on it's northern and eastern flank producing a lot of cloud and patchy rainfall during Tuesday. Due to the dynamics associated with the low pressure system becoming weaker as we go through the coming 24 to 36hrs there is a chance that rainfall may decrease for western and central parts of SA.


As the upper low begins to move eastwards into the eastern inland of SA and then on into western NSW and QLD, the system will encounter a new surge of moisture coming down from northern Australia, which will in turn be lifted into widespread cloud and areas of rain with a few thunderstorms.


GFS Precipitable Water Values - Next 5 days - Valid Monday 31st May 2021.

Showing that moisture coming down the pipe through the upper northerly winds from the NT through outback SA and into the eastern inland ahead of the upper low, lifting a large mass of moisture into areas of rain and a few thunderstorms.


The upper low and trough will get a kick along by a shortwave mid week through southeast Australia, which may in turn help invigorate the low pressure system as it passes east through the eastern inland. The low pressure system as it strengthens will lift off the east coast and conditions will stabalise through inland areas into the weekend with a return to frost in the east.


Out west, things will be fairly quiet this week with high pressure ridging through the region. Over the northwest, moisture oscillating offshore will continue to meander around the Indian Ocean with some rainfall moving onto the land from time to time, not being ruled out for the Pilbara and Gascoyne regions.


For the QLD coast and into the eastern Arnhem Land regions, scattered showers will continue at times with easterly winds continuing throughout the period. A weak upper disturbance next week could see showers increase for the QLD coast north of Bowen.


Next week it remains a low confidence forecast with model madness continuing relating to another strong upper low and strong long wave trough moving over southern and eastern parts of the nation. Some modelling has had widespread cloudiness and rainfall with colder conditions at one time or another, then the next run it is gone. This is expressing uncertainty next week and for now the general rule on here is carrying the low confidence forecast as we go through the coming week from Sunday.


GFS 00z run - Valid Monday May 31st 2021 - 500mb/18000ft flow pattern.

Underneath will be the surface pressure pattern and the associated rainfall distribution expected.


Tuesday 1st of June 2021.

Upper low in the Tasman Sea moving away, ridging over the southeast and east, moving eastwards sending a warmer flow into the eastern states. Another upper low over southern WA is moving east into SA during the day with cloud building over much of the central portions of Australia. Another ridge building into WA is clearing skies and easing winds for the SWLD, though cloud and rainfall may persist with a trough offshore the coast of WA. The typical high amplitude wavy flow.

Showers, with local hail and thunder for the Eucla coastline will continue on Tuesday with a cold windy day. Showers easing from Esperance eastwards during the day. Cloud increasing over central and eastern SA with patchy rain developing. Showers about parts of the NT coasts during the morning and along the QLD coast north of Mackay will be light and isolated with falls less than 5mm. After a cold start for the southeast and east, partly cloudy and warmer with a northerly flow developing.

Wednesday June 2nd 2021.

Upper low moving to the east and weakening a little as it approaches Ceduna. Areas of cloud and rain developing as it crosses east into SA. A ridge in the east moving off to NZ will keep the region warmer in a northerly flow. A new ridge over the southwest of WA will keep skies clear and a cold night and morning is expected with light morning frost possible but sunshine to follow. Still have cloudy skies over northwest areas of the nation with a trough offshore. Heights where they should be over the north of the country.

Rain and a few thunderstorms breaking out over SA and the southern NT then onto southwest QLD into western NSW with a trough picking up moisture that is sitting through the upper and middle levels, drawn in upper northerly winds ahead of the low. Showers about the south coast of SA may have small hail and a rumble of thunder, especially near the centre of the surface low. This run a little stronger with the low over SA. Showers developing along the QLD coast as winds veer into the east. Cloudy skies over parts of northwest WA and a morning shower possible off the Darwin and Dundee coasts in the NT.

Thursday 3rd June 2021.

Upper level low begins to move into western NSW with a broad area of circulation. Long wave trough approaching Bight waters will start to see the system gather speed over NSW. A ridge over southwest WA will bring further cold nights but lovely days. Zonal flow over the north keeping the weather dry with the main wave action to the south.

Surface low situated over southern NSW may bring a reasonable band of rain and thunderstorms through southern QLD, through much of NSW and northern VIC on Wednesday into Thursday with moderate falls. Showers continuing for coastal areas of SA, southern VIC and TAS with a weak front approaching. A few showers for the QLD coast. A morning shower possible off the Daly coast in the Top End otherwise dry elsewhere under high pressure ridging in over the southern and central parts of the nation, leading to cold nights once again over the WA and western SA regions.

Friday 4th of June 2021

The upper low begins to lift out of NSW helped along by a cold front over Tasmania. Ridging over the southwest beings to strengthen and take hold of much of WA's weather. Upper level heights below normal over QLD, with below average temperatures possible during the day time with colder air in the atmosphere.

Rain will be ending early in the day over eastern QLD and NSW, with clearance from the west with improving temperatures. A few showers moving through southeast Australia with light falls for VIC and TAS in a southwester. Snowfalls are possible in TAS with local hail and thunder in the south and west. Cloudy skies over NW WA with the bulk of the rain sitting offshore. Elsewhere, fine dry and temperatures near seasonal after cold starts through inland WA and SA.

Saturday 5th of June 2021.

A new upper low forms on the trough over eastern QLD with unstable air. A strong flat ridge moving through southern Australia, beginning to clear skies over VIC and SA through the day. Heights about normal through the northern parts of the country with temperatures near average in dry weather. A weak front will approach the western coast of TAS later in the day.

Showers easing over the east coast of NSW and QLD with the secondary upper low moving off. Cold starts over inland WA, SA, VIC and NSW with light winds and clear skies. Fine over northern Australia with a drier easterly, fresh at times during the day, lifting fire dangers. Showers and strong northwesterly winds by afternoon and evening for western TAS. Winds may freshen over southwest VIC later in the day with some late cloud.

Sunday 6th of June 2021.

Flat ridge being pushed north over mainland Australia with a long wave trough beginning to lift north through the southern ocean. A cold front will move over TAS, VIC and southeast SA. A zonal flow over the nation is fairly stable for now. Heights about normal on the north of the ridge over northern Australia with seasonal temperatures and dry air.

Cold front draped in the westerly parallel to the wind flow will move through southern WA and snake across the Bight to clip southeast SA, southern VIC and TAS with windy weather and showers, heaviest in TAS. High pressure elsewhere will keep things dry for the majority of the nation with increasing clouds possible over the northwest of the nation with moisture building offshore.

A week from today - Monday 7th of June 2021.

Ridging over the east beginning to weaken. A long wave trough beginning to strengthen south of SA with a strong cold front riding up from the southwest. A mildly unstable northwest flow aloft may produce cloud. Ridging back over in WA redeveloping west of the state continuing the dry weather.

That front slams through the southeast with a band of rain and much colder air through southeastern areas, possibly the coldest air of the year so far. Showers increasing with local hail and thunder with snowfalls down to low levels over TAS extending to the mainland later. High pressure over WA keeping the state dry with cold temperatures overnight. This high positioned here will help enhance the southerly flow from well down south bringing in that cold air. Elsewhere, dry and seasonal ahead of that cold surge through the east.

That is a very cold look for the SE with thickness values down well below average for the region. Strong high over the west, really propelling that southerly flow across the eastern states.

The Euro Model is also on board for this system riding through the southeast next week with some very cold air moving over the southern and eastern inland. Strong winds, heavy showers hail and thunder would be in place. Snowfall down to low levels too. So this would easily bring the heaviest cold weather of the year thus far.


Euro 00z 500/18000ft flow pattern Tuesday June 8th 2021.

Euro and GFS diverge in what to do with the system beyond this period with GFS moving it through as a wave while Euro cut it off into a large upper low again over northern NSW and QLD with very cold air. A low pressure system would form on the coast with heavy rainfall along the NSW or QLD coasts under such scenario. It is a severe weather look for the east. Out west the dry would continue under a strong high.


It is a high amplitude pattern that is establishing next week, with low confidence at this time on who sees what.


Euro 00z 500/18000ft flow pattern Thursday June 10th 2021.

Rainfall for the next 10 days - Euro 00z run Valid Monday May 31st 2021.

Heavy rainfall attached to the deep low next week can be seen over NE NSW and SE QLD. Rain also off WA needs to be watched to see if that comes onshore and links up with a cold front mid month for the west coast with climate models suggesting heavy rainfall redeveloping out west mid month.

Southeast areas could benefit from days of showers and cold gusty southwest winds in the wake of the system next week, with reasonable falls about SA, VIC and TAS.

Want more weather information for your region? Email me at karllijnders@weathermatters.org for more details.


0 views0 comments