NSW - SHOWERS DEVELOP ALONG THE COAST THIS WEEKEND, MAY EXTEND INLAND. FROSTY STARTS SOUTHEAST.

The weather is offering a bit of everything for everyone this week, with a pressure trough forecast to develop off the northern NSW coast before extending into QLD. The result will be showery periods from the weekend and into next week with moderate falls.


In the meantime, we have cold and clear nights on the way with a ridge sitting over the southeast of the nation, this supporting the formation of frost and many locations recording the coldest mornings of the year so far. The weather is forecast to warm up slowly through the outlook period with temperatures during the daytime turning well above the average. The humidity will also increase, and this should offset the frost risk during the weekend.


Next week, the showery weather will persist over the coastal areas in onshore winds and they may become heavier as the flow tends more northeasterly. The moisture is forecast to present further west through the state and there may be a few showers about during Sunday into next week with light falls generally, but the bulk of the wet weather is forecast to be coastal.


Out over in WA and SA, there is a series of fronts forecast to approach and pass through with a deeper moisture supply being fed into the long wave, leading to a broad cloud band developing with areas of rain spreading from west to east across the country. This weather will offer the inland the next chance of more widespread rainfall, especially if the frontal weather merges to with the moisture being drawn in via the northeast winds.


So there is potential for heavier rainfall next week and a colder shift to end the month, so plenty of weather on the horizon and given the high amplitude pattern in play, severe weather is possible.


Let’s take a look

FORECAST

Rainfall Next 10 Days

Rainfall totals should start to increase from about Friday over the northern coast from Taree into QLD, with moderate falls via easterly winds possible about the QLD border. Saturday and Sunday, the shower coverage should extend southwards along the coast to about Sydney with moderate falls possible to about there, and lighter falls through to the VIC border. Inland areas, especially the northern and western inland could see a few showers and possibly a thunderstorm with a weak trough in the region but falls patchy at this time. As the high shifts slowly east ton the southeast during early next week, we could see the flow turn more northeasterly leading to heavier rainfall along the coast and then the falls becoming a bit more scattered over inland areas. Once we get a strong cold front approaching the state we will likely have moisture and cloud increasing from the northwest, merging with the existing moisture and a broader band of rain will spread across the state. A colder shift with widespread showers to follow and local hail and snowfalls over Alpine areas is also gaining traction towards the end of the month and to kick off June.

Coastal areas could fair quite well in terms of further rainfall later this week into the weekend with a deep moist onshore flow combining with a weak upper trough over QLD. Between the high to the south and the system up north, there could be moderate showers over about 4-5 days, some locally heavy rainfall possible closer to the QLD border. Rainfall should begin to wind down by next week as the flow turns northwesterly.

Frost Risk Forecast - Thursday to Saturday.

The frosty nights start tonight and continue through to the weekend with some pockets about the ACT and Southeast of NSW into far eastern VIC, looking at the first severe frost of the season. Once we get the northeast flow developing with moisture being drawn in over the weekend, this will lift overnight temperatures and fog areas will replace the frost followed by more lovely sunny weather.

MEDIUM TERM FORECAST

May 25th-June 1st, 2022

Rainfall Anomalies

There is more agreement that once we lose the strong cold front and rainfall at the end of next week through the southeast that further showers will follow in a westerly wind regime over southern Australia but seasonal expectations for now. The weather turns wet again from the northwest of the nation through to the southeast with some chance of further above average rainfall likely for the interior of WA, through SA and into western NSW possible. Further rainfall knocks on the door over the southwest of WA during this time as well.

Temperature Anomalies

The warmer bias strengthens over the east with the northwest flow strengthening ahead of a series of cold fronts. The western interior still cooler than normal with the westerly wind regime starting to progress into SA through this period with that expected to move further east during the end of the month into early Winter. So, this could be the last few days of 20C+ weather over a widespread area in the south and east until about September.

DATA - Refer to video for more information


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

More information can be found in the video tonight to break down the quite volatile picture that is giving you the larger rainfall spread right across the nation. I will have more in the models and rainfall update coming up from 8pm EST.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The dry cold shift over the southeast will lead to areas of frost tonight with some of that severe in places. Deeper moisture spreading through from WA into SA hits a brick wall and little rainfall will move beyond where it is right now, though high cloud will drift across the nation. Deeper moisture coming in via easterly winds will feed an upper trough over QLD bringing heavy rainfall from the weekend before clearing, but showery warm soupy easterly winds continue into next week. Next surge of deep moisture from the Indian Ocean reaches the west of the nation Sunday and traverses the state before moving into the Bight along a weakening cold front. Another surge of deep moisture reaches the west of the nation again on Wednesday next week and once again later next week with one or both of these waves to spread rainfall chances across the nation from west to east.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z Euro - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - rainfall numbers will continue to bounce around for the inland and hence why there is not much change to the charting from me tonight but certainly keep abreast of the forecast notes and videos morning and night to follow the trends. This will change from run to run so don't count what the yr.no apps etc say as gospel.

More coming up from 8pm EST with a look at the models and rainfall


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