MONDAY MORNING WEATHER - A NEW WEEK AND WE START OUT SETTLED. MORE RAIN IS COMING THOUGH

Updated: May 16

Who gets exactly what is the more interesting point, as it could be areas that have missed out, picking up on some beneficial falls while areas that don’t need any more for a little while, could be getting more interruption to the planting season and damage to crops with further falls coming through?

Looking at the coming day and most of Australia is settled today. We have a few showers up over the QLD coast, a few lingering over the southeast coast in onshore winds, and a few thundery showers possible over the northeast tropics with the onshore winds.

There is some cloud cover thickening over western interior parts of the country thanks to a jet stream that is feeding a weak trough in the region. Some patchy rainfall is possible over parts of the Pilbara and Gascoyne and the adjacent inland but not much to write home about.

The next weather makers on the board are over in the west with a low-pressure system approaching the SWLD and invigorating a trough. The other weather maker, in the east, a developing trough along the coast is being pushed inland and fed by moisture from the jet stream and the easterly winds leading to a broad cloud band developing here with rainfall potential.

Starting with the western system and this one is complex. A trough over the interior stretching back over the Indian Ocean is forecast to bring a large cloud band into place and once the low approaches the southwest, this is where we see a band of rain develop and increase in size as the low rolls into the moisture. Some locally heavy falls are possible trough the central and western interior but these will sit mainly north of the Ag Areas.

The SWLD should see widespread showers and scattered thunderstorms with the chance of hail moving through as the broad low washes over. No severe weather is expected at this time with the system sitting above 1005hPa.

This system is forecast to move east and into SA mid week with areas of rainfall moving into the state via the cloud band to the north and the low moving into the Bight.

Over in the east, the showers are expected to increase in coverage as a trough moves through the region from east to west, propelled by the easterly winds. Scattered showers along the coast with possible thunder will see rainfall totals exceed 10-20mm in many areas from mid-week. Once the trough stalls out over the interior, we will see a band of showers and thunderstorms develop for the Central districts extending southwards into inland NSW with some moderate to heavy falls possible, that could take place from the weekend..

The southeast looks to sit under a stationary high for a number of days leading to cold nights and sunny days with frosty mornings but lovely days. Rain free days look to last to about early next week.

The strongest cold front of the year is also on the board as well for WA this weekend with strong winds and heavy rainfall with a high amplitude pattern developing.

Let's take a look at the latest details.

FORECAST

Rainfall Next 10 Days

Rainfall has contracted to be mainly along the QLD coast with onshore winds. The rainfall over in the northwest is patchy at best today with the trigger for widespread rainfall, not quite present, but it is on that approach, that means a broad rain event will start to emerge from tomorrow for the west. The rest of the nation is dry and quiet through mid week. Now the western system, as mentioned above evolves from tomorrow night through Wednesday and advances eastwards into SA via the jet stream and into the southeast or eastern inland with light and patchy rainfall and thick high cloud. The heaviest of the rainfall is contained to the highest instability which will be found over the SWLD of WA and with the upper trough over the interior. So these areas can expect moderate rainfall. For the east we have onshore winds providing a few showers today but these increase with the trough deepening as it heads westbound into the interior. Some moderate to heavy falls are possible with thunderstorms if they develop over inland areas as the trough stalls out mid to late week. Showers are set to increase along the NSW and QLD coasts with moderate falls possible. There is the chance that rainfall does become more widespread over the QLD coast and central interior with a trough deepening. How far the rainfall moves west remains to be seen but the ridge could begin to hold firm. The next major rainfall event looks to be over SWLD WA with another cloud band expected to form on its northern flank over interior WA. That could be the strongest cold front of the year, and if so, SA and VIC into NSW should pay attention to the rainfall coverage with this feature as well. While dry in these areas this week, we could see better rainfall chances to end the month with some luck.

THUNDERSTORM FORECAST

Thunderstorm Forecast Monday

Thunderstorms are forecast continue along a deep moisture feed across the northwest to the southeast of the nation. Thunderstorms are forecast to be non-severe. Thunderstorms are also possible near a weak trough over the northwest inland of WA with some moderate falls over the Pilbara. A front approaching TAS with a cold air field could produce some scattered showers and thunderstorms with small hail. Chance of a morning storm offshore the NT coast.

Thunderstorm Forecast Tuesday

A trough deepening over the western interior of the nation is forecast to produce showers and thunderstorms with moderate falls, that extending southeast towards areas west of Giles to Warburton. A low-pressure system approaching the SWLD may produce a few showers and thunderstorms later in the day. A weak trough could produce a few thundery showers near the Wide Bay during the day.

Thunderstorm Forecast Wednesday

A cloud band is forecast to move through the western interior with moderate rainfall. The moisture injection producing a large cloud band. The low-pressure system is forecast to move through the SWLD with the chance of thunderstorms producing small hail and gusty winds.

Thunderstorm Forecast Thursday

Thunderstorms are forecast to continue over the eastern inland of WA with a low-pressure system dragging a cloud band through the state. The low may produce a few thunderstorms with small hail.

Thunderstorm Forecast Friday

Thunderstorms are possible near a developing trough along the east coast of QLD between Hervey Bay and Townsville. Some thunderstorms may produce some moderate falls of rain, but no severe weather is expected. An odd thundery shower or two over the central inland of WA is possible with a lingering upper-level trough.

Frost Risk Forecast - Tuesday through Friday

A drier airmass is forecast to settle in from Monday and with clearer skies and the high-pressure ridge moving in, there is the chance of frost developing. The peak of frost is forecast from Wednesday and Thursday before easing later this week.

Medium Term - May 22nd-29th 2022

Rainfall Anomalies

Northwest cloud bands look to continue over the nation with moderate rainfall extending underneath the cloud band. The moisture may merge with moisture from easterly winds in a warm airmass leading to widespread rainfall above the average once again a decent chance over parts of eastern QLD and through NSW. The SWLD with persistent onshore winds and frontal weather moving through bringing bursts of showers and colder conditions. Generally seasonal rainfall is forecast over southern parts of the nation with light to moderate rainfall.

Temperature Anomalies

A warmer phase looks to be in place over much of the nation with a broad area of high pressure in the east directing warmer than normal weather from northwest Australia into central and eastern areas of the country. Higher humidity values over the nation will support warmer nights as well. The cooler bias looks to continue over western parts of the nation with thicker cloud and the chance of further influence from the Indian Ocean. But the position of the high-pressure system over the southwest of the nation will continue to pump in onshore winds.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.


SOUTHERN ANNULAR MODE - TURNING BACK POSITIVE

The overall trend is for the SAM to move back to a positive phase throughout the outlook. This will lead to showery weather along the east coast and the chance of showers and thunderstorms developing over eastern inland areas of QLD and NSW. The frontal weather is forecast to move towards southern Australia, but the positive SAM will suppress the frontal activity for the period which is quite normal for late May.

12Z Euro Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

It is looking much more settled for large areas of the nation thanks to the high pressure sitting over the southeast and east this week. So that ridge will cover much of SA, VIC and NSW/ACT. Cool to cold starts and sunny mild days are forecast this week once we lose the showers today in the southeast and the cloud clears from mid week. Much of the inland away from the coast generally fine for the next week. Out west, the wettest part of the nation is right here with a deep trough over the inland drawing upon moisture from the northwest leading to widespread showers and thunderstorms with locally heavy falls. A low pressure system that is moving in from the west is forecast to spread moderate showers but disorganised coverage with some areas recording reasonable follow up over the SWLD but others seeing mainly light falls. Then the system falls apart heading east as it hits the ridge and blocking pattern in the east. A low pressure system may form off the QLD coast during the weekend or early next week as showery easterly winds increase with the high moving into the Tasman. The low pressure system is foreacst to move west over land on some modelling, but not all models agree making the forecast very low confidence. Overall the west of the nation looks wettest, scattered falls possible in the eastern inland but the southeast through to the central and northern inland looking driest for now. There may be some rainfall eventually come into SA and VIC later in the period but this remains to be seen.

12z Euro Precipitable Water Anomalies - Next 10 Days

A drier westerly change is forecast to move through the south and southeast of the nation today which will allow temperatures to fall away from where it has been, especially overnights, which have been running well above average for many of you through SA, VIC, NSW, QLD and the ACT. The temperatures will return to seasonal values with the drier air moving through. But for the west, the humidity values are set to increase once again as a deep moisture plume surges in from the Indian Ocean leading to thickening cloud and rainfall chances but warmer overnights but cooler days. Next week, the moisture returns over eastern parts of QLD and NSW with onshore winds. This will see the days turn more humid and the rainfall chances increasing once again and by the early parts of next week, the nation is once again set up to turn wet with above average moisture folding over most areas.


12z Euro Rainfall Accumulation - Next 10 days

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12z GFS Rainfall Accumulation - Next 10 days

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12z CMC Rainfall Accumulation - Next 10 days

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12z Euro Rainfall Accumulation - Next 15 days

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12z GFS Rainfall Accumulation - Next 16 days

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More coming up throughout the day with your Winter Outlook for your state and territory later this morning and state-based forecasts tonight. The Winter information is very important as we are looking at a rough time for many!