NATIONAL WEATHER PICTURE - SUNDAY 23RD MAY 2021

Headlines


  • Wet and windy in the west.

  • Warm and dry in the east and south.

  • Hot and dry over the north of the country.

After what has been a cold and prolonged cloudy spell over southern Australia, the weather has finally turned warmer with a good northerly flow developing around a high that is in the Tasman. It has brought a stunning weekend of weather to the eastern states.


Out west, a cold front has already passed through on Saturday bringing up to 70mm of rainfall in some locations in the SWLD. Another front is in the process of moving through this evening with rain and thunderstorms ongoing, with a much colder airmass. The pattern, well and truly flipped out west.


Over the east, a couple of showers dancing offshore today have crossed over various parts of the coast producing light falls, with weak onshore drift. They should be gone early in the new week.


The north, well above average in terms of temperature with humidity hanging on again.


National Satellite - A large cloud band navigating the jet stream is producing light rainfall through outback WA with most of it fair weather high cloud for now - the high in the east, weakening the rainfall potential for now. A piggy back cold front through SWLD of WA is producing showers and thunderstorms, this is the system to bring the rain and windy weather into the SE states during Monday-Wednesday.

Widespread rainfall of up to 70mm fell in SW WA overnight and a further 10-20mm has fallen today. Gusty winds, hail and thunder will continue overnight before a stablising high pressure ridge moves in later Monday.


Rainfall for the last 24 hours - WA Rainfall

Rainfall to 3pm WST

The overall pattern will turn wet and windy for the southeast of the nation with a gusty change moving into the southeast. Well above temperatures ahead are expected to be replaced with a colder change Tuesday. Sheep graziers should be advised of a dramatic shift in temperatures once again.


Temperature anomalies - May 24th 2021. Temperatures are well above average with the pattern breaking down as we go through mid week. Much colder weather developing later on this week over the east.

This is the temperature anomalies Friday showing that push of very cold air that will likely spread north through the Tasman with the wettest weather staying in NZ, but the high will help loft that into the east and the north around the high circulation. This will see a nice push of dry air and cooler weather hit the NT and QLD.

Rainfall wise, we are tracking wet weather for a good part of this week over the west of the nation, that will likely be the wettest part of Australia. Moderate falls initially for SA, VIC and TAS with some heavier falls about western TAS. Light falls for NSW with some moderate falls over the slopes.


Rainfall for the next 2 weeks - Weather Matters. Valid Sunday May 23rd 2021.

The overall sequence for rainfall is becoming focussed over WA. There is a large long wave that has passed through Sunday, with that wave weakening as it travels east. Another strong wave of low pressure approaches later this week, with the potential for a severe weather event to unfold as a low pressure system deepens over the SWLD.


Heavy rainfall leading to areas of flooding and strong winds are possible under current guidance, but more refining will be needed before I begin issuing forecasts on specifics, which will likely be available here on Tuesday.


But no doubt over the coming 2 weeks, a wet phase will continue for the west coast, with dribs and drabs further east.


Essentially dry for much of QLD at this stage.


However, a deep layer of moisture may be pulled into the central and southern inland parts of Australia during the early part of June. This could lay the foundations for more cloud and rainfall spreading over wider areas as we begin winter, which may involve QLD. So that system should be watched.


Precipitable Water Values - next 2 weeks. Note the large amount of PW coming through the interior in early June connected to a low moving south. If that low can move more east than south, then more rainfall will develop over southern and central parts of Australia. One to be watched. GFS 00z Precipitable Water Values - Valid Sunday May 23rd 2021.

So for areas that have missed out, there is still opportunity for rainfall to develop as we kick off winter. The bulk of the rainfall, with the heaviest falls will remain coastal for now, but a rogue system is all it takes at this time of year, to bring a month's worth of rainfall to inland areas. This rainfall pattern at this time of year is very different to summer rainfall, and if you live away from the coast, you can expect long dry spells. That is very normal in neutral climatic years.


For snow lovers, there is not much on offer for the Australian region, with the airmass either too dry and cold in the wake of frontal weather with incorrect rain bearings, or too much tropical moisture coming into the jetstream and warm air advection stifling snow bearing systems across the region, so it may be cold, but at this stage, not much snow is on offer.


Snowcast - Next 2 weeks - GFS 00z run Sunday May 23rd 2021.

The pattern is trendy more wavy as we go into June with cold fronts likely peaking further west over WA for now, with the position of the long wave trough but areas of southern Australia will pick up on rainfall and gusty conditions too. The east coast may experience it's driest spell of the last 12 months coming up, with not too much rainfall anticipated....for now.


Mean Sea Level Pressure Pattern - Valid Sunday May 23rd 2021.

With that wavy flow, the weather should be much drier over northern Australia with cooler air and a much drier southeast wind moving in which is fantastic for those who have been battling this long term humidity that won't leave!!!


You can see from above the rainfall really kicks out towards the equator, where it should be at this time of year, leaving the north of Australia nice and dry.


Want more weather information that is helpful for your part of the world? Email me at karllijnders@weathermatters.org for more information on how I may be able to help you.



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