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

Headlines


  • A deep freeze to start the day in the southeast but sunshine to follow

  • Showers and heavy falls continues for southern WA today.

  • What about the rainfall potential out east mid week?

Absolutely freezing weather to start the day over the east, with clear skies, light winds and sinking air motion allowing the radiational cooling to be maximised. Once we get the stats at 9am, there will be new May records set today across northern VIC and southern and central NSW for overnight minima. A nice day will follow the overnight freeze.


Showers with areas of rain for the south coast of WA continues with onshore southerly winds wrapping rain around a low. Drier weather has developed for the west coast with the rainfall parallel to the coast, however it is cool and breezy across southern WA with a colder airmass moving up from the south. Rain will develop for eastern areas this afternoon.


And that low over WA, that remnant circulation will run into better moisture over the east and north, and start to produce widespread rainfall over eastern SA through the eastern states during mid to late this week. Offering inland areas the best rainfall opportunity for about 6 weeks.


National Satellite - Valid Monday May 31st 2021.

Deep low off the south coast of WA is producing strong winds and showers on Monday. A broad band of cloud with patchy rainfall over eastern WA is moving into western SA on Monday with light falls. Elsewhere it is clear skies with high pressure controlling the rest of the nation.

Widespread cloud and patchy moving through eastern WA and into western SA on Monday. High cloud streaming over SA is not producing rainfall with the air too stable over the east at stable at the surface. Low pressure is moving slowly east this morning with showers and hail with some thunder over the southern coast. Showers will develop over the remainder of the coastline during the next 2 days as the low moves east.

Rainfall has been heavy over the past 72hrs with some locations now up to 150mm for the event along the south coast of WA with further rainfall underway. Top fall of 74mm inland Albany to Sunday morning.

Heavy falls retreated to the south coast with the low winding up east of Albany. Top fall of 70mm east of Albany overnight with further showers underway.

Temperatures to start the day, absolutely freezing with widespread frost, severe in many locations and reports of a freeze over parts of southeast NSW and northeast VIC. Some areas saw temperatures as low as -9C!


Temperatures - 7am EST Valid Monday May 31st 2021.

Temperatures near record values for May over the southeast of the nation with severe frost and freeze conditions. Cold through the interior after a clear start. Still above 20C over the north of the nation with a little more humidity ahead of a dry surge, but a nice 9C at Daly Waters this morning represents the dry surge moving north.

Zoomed in view of the SE of Australia shows that near record cold morning with temperatures well below average. Canberra down to -7C this morning in some locations. -8C in Cooma and -7C at Goulburn as of 7am EST.


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

Upper low over the southern coast of WA will continue to drive showers for the first half of this week. Those showers will run along the south coast of SA and very light falls over the western inland of SA. The upper low will run into better moisture over the east with more rainfall breaking out mid to late week with moderate falls. Another low pressure system in the day 7-10 range over the east may bring additional falls, but it is low confidence on that event.

GFS Rainfall for the coming 2 weeks - Valid Monday May 31st 2021.

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

Modelling and Analysis.

GFS 500mb/18000ft 12z run of the flow pattern showing the movement of weather systems above the surface. Underneath this chart is the corresponding synoptic pattern and rainfall distribution. Valid Monday May 31st 2021.


Monday 31st of May 2021.

Upper low with a trough on the eastern side of WA bringing rain to some parts. A ridge in the east is slowly moving east but is responsible for the very cold start to the day over the south and east. Low over NZ bringing wild weather to that country is moving away and the seas and strong winds easing over the Tasman. That will open the door for the low in WA to move east this week.

Monday 31st of May 2021.

Widespread showers about the south coast of WA bringing moderate falls. Patchy rain moving in from WA into SA today, with light and patchy falls. Relatively dry elsewhere with isolated showers about the eastern coast of the NT and northern QLD, with light to moderate falls possible in these. Dry with very cold starts easing for the south and east.

Tuesday 1st of June 2021.

Upper low is moving east over the southern coast of WA into SA, with patchy rainfall over western inland areas of SA but more widespread showers will be confined to the coastline at this time, with a dry slot of air in place over western SA. The ridge moving off the coast with fine weather still continuing over the east and north of the nation with warming temperatures after a cold start. Another ridge of high pressure clearing skies over southwest of the nation with light winds, meaning cold nights will return.

Low pressure moving into SA waters with gusty showers wrapping into eastern WA and western SA. Rain developing through central and eastern SA with increasing cloud, thanks to a better moisture profile for the low to work with. Showers along the QLD coast will remain light. Cloud increasing over the southeast with a warmer day in northerly winds after another cold start. Light rainfall will increase over SA during the afternoon and evening.

Wednesday June 2nd 2021.

Upper low moving over central and eastern SA with a shortwave passing to the south of this over southeast Australia. A new ridge over southwest WA, helping to nudge the low along to the east. Ridging now moving over NZ with a northerly flow over the east lifting temperatures ahead of the next rain. Warm and dry over the northern states.

Widespread rain breaking out over eastern and southern SA moving east into western and northern Victoria with light falls but more moderate rainfall over western and northern NSW and southern QLD is expected. Isolated thunderstorms bringing heavier falls through the western inland of NSW. Cloud building over the remainder of the east, with light and patchy rainfall developing later in the day, but some parts of southern NSW and central and eastern VIC may miss out on rainfall. Showers will clear the southern coastal areas of SA during the day. Fine and mild over the west and north with clear skies under a ridge.

Thursday June 3rd 2021.

Upper low progressing eastwards through NSW with unsettled weather continuing. A shortwave passing through the southeast of VIC will bring a cooler change with showery skies. Colder airmass will move over TAS during the evening with the chance of snowfalls returning. Upper ridge over WA strengthening with warm weather developing as winds veer into the east.

Widespread rain and a few storms over southeast QLD and eastern NSW will clear from the west, with some moderate falls. Showers developing for the southeast with colder air to follow with hail and thunder for TAS. Light falls generally for the southeast, but some heavier falls for western TAS. Snowfalls developing to 600m during the evening. Fine out west and across the north, however some cloud may increase over the Pilbara with evening rain possible.

Friday 4th of June 2021.

Upper low absorbed off the east coast but the fast moving cold front from the SE of Australia during Thursday and progressing east. A new ridge building over southern parts of Australia with dry skies and cold nights returning. A little weakness in the ridge hanging back over parts of central NT and QLD will likely remain in active for now.

Cold front and low move offshore the east coast, with residual showers in a southerly wind as high pressure ridges in over the southeast. That high will keep the rest of the nation dry with light winds and cold nights. Warmer out west. Some patchy rainfall is possible about the Pilbara coast but light falls if it makes the region.

Saturday 5th of June 2021.

Ridging over most of southern Australia, with again relatively fine and dry skies. Long wave passing to the south of the ridge in a zonal flow keeping frontal weather to the south of Australia for the weekend on this current guide, but there has been multiple looks at the weekend from various models, so it is a low confidence forecast. Upper low over western QLD will become slow moving and also contribute to cooler day times.

Most of Australia will be dry on Saturday under the current guide, once again after cold nights with frosts, some severe. A cold front starting to move north out of the westerly flow to the south of the nation, may bring some showers to the southwest of WA later in the day and showers increasing for TAS as the same front sliding over the region with moderate falls across the west coast.

Sunday 6th of June 2021.

Ridging moving over southern and eastern Australia, it is progressive as a westerly wind belt rears up from the southern ocean. Upper trough over NT and northern QLD will remain in active will little moisture to work with at this time. Another ridge is building southwest of WA may continue to bring cloudy skies to the south coast in the wake of a new wave pushing through Bight waters.

Strengthening northwest winds over southern Australia with showers developing for southeast SA, southern VIC and rain areas with moderate to heavy falls for western Tasmania. Showers developing about the FNQ coast with onshore winds and that weak upper low over the inland. Showers may also develop over the far northwest Pilbara with moisture lurking offshore, but cloudy skies may spread across the nation with the jet stream pulling in the moisture in the upper northwest flow. It will be dry away from the southern coastline of Australia through the weekend after cold starts.

10 days out - Wednesday 9th of June 2021.

High amplitude pattern with a strong ridge in the west and a strong long wave passing over the east with a fast moving flow. Upper trough still sitting over the central and northern QLD coast. Otherwise heights where they should be across the north.

Cold front moving through the southeast bringing cold and windy weather with widespread showers developing. A large high over the west will be the dominating force with clear skies and light winds over the west and north of Australia. Temperatures over the nation will be warmer in the north and northwest, and colder than normal over the east and south. But it is a low confidence forecast with again, this model suggesting widespread rainfall in the east in the last run overnight.

The Euro model in comparison for the same day looks very different with a deep upper low over the eastern inland driving rain and thunderstorms and a much colder airmass. GFS, ACCESS and CMC have all had this same look so this will continue to evolve in the outlook period. I would expect GFS will bring that back in some form in the future runs.


500mb/18000ft Euro Model - Wednesday June 9th 2021.

Upper low with very cold air driving unsettled cold weather over the eastern inland. Ridging, not as pronounced over the west of the nation will support this system to move north in an upper southerly airflow. The zonal flow that GFS has is well to the south of the nation. Heights also well below average over northern Australia with cooler temperatures.

As a consequence more rainfall is being picked up by the Euro model during the 7-10 day window. But it is a low confidence forecast as we go through Sunday onwards. For now we will focus on the first event that comes this week, but know there is something lurking next week as well which could bring mixed blessings to the east.


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

Need more weather information for your part of the world? Email me at karllijnders@weathermatters.org for those tailored forecast packages.

0 views0 comments