MORNING WEATHER UPDATE - THE COLD AIR IS MOVING NORTH.

The dry air following suppresses rainfall chances nationwide from mid week as high pressure come in, combining with the dry air to bring clear skies and below average temperatures for much of the south.


Up north, Darwin, 37C ahead of the dry shot of air coming in from the south and southeast. That is a sign of the times! Warmer days will descend for most of the nation come the weekend so the cold snap thankfully for the inland is short lived.


Here is the latest.

FORECAST

Rainfall for the next 10 days

Rainfall limited to the southeast of the nation for the coming 2 days, as low pressure works it's way through, but winds will veer southerly and dry, seeing rainfall chances drop away Tuesday and clear the east Wednesday. The remainder of the week is dry nationwide under high pressure. Rainfall chances will return from later this weekend over the east and about the southwest of the nation from this time next week with a trough developing out of the heat through WA. Moisture will also increase from the Indian Ocean and via easterly winds through QLD and NSW, with the SAM tending positive.

Thunderstorm Forecast Monday.

Thunderstorms are possible about southeast SA and along southern VIC with small hail and gusty winds forecast with thunderstorm activity. There will also be some brief heavy rainfall but at this stage flash flooding is low with a dry airmass in place and the cells moving through at pace. Storms will fire along the boundary of cold air during Monday afternoon through southern NSW. Over the northeast of NSW and southeast QLD, isolated mid level thunderstorm activity may develop producing gusty winds and brief heavy rainfall. Severe weather is unlikely for all regions at this time, but in spring time expect the unexpected.

Small Hail Risk - Monday.

Cold air showers and thunderstorms will be capable of producing small hail and gusty winds through Monday, extending north through the afternoon into Southern NSW and the ACT where the hail intensity may be moderate to heavy given the day time heating process. The hail is likely to be below severe thresholds. The risk decreases tonight as the air turns more stable at the surface over inland areas but could persist over southern and eastern VIC and TAS.

Damaging Winds Forecast Sunday into Monday

Damaging winds are ongoing in the tightening pressure gradient as the cold air lifts north into the southeast of the nation. On Monday, strong squalls over 90kmh are possible with a front passing north through the state and into southern NSW during Monday afternoon. Conditions should ease later Monday into Tuesday from the west.

Snowline Forecast - Monday into Tuesday

The snowline will drop well below 1000m during Monday into Tuesday, possibly as low as 500m, however with the airmass quite dry, this will see falls not accumulate, rather more flurries with the passing showers at this time.

Farmers and Graziers Forecast - Monday to Wednesday.

As mentioned for 5 days now, the event is on the doorstep and this period of cold will place the young animals at great risk, especially through southeast SA, VIC and NSW.

Frost Forecast Wednesday Morning

Frost is expected to widespread, I will add in more specifics when we get closer tomorrow, but this is a preliminary forecast and a heads up on potential frost for large parts of the state. Frost also possible along the divide above 800m during Tuesday morning and again on Thursday morning but this day is the most widespread frost over multiple states.

DATA

Euro 00z - Surface Pressure Pattern and Rainfall - Next 10 days

The pattern continues to be in good agreement with the GFS with strong cold front passing through today the main weather to watch nationally away from the high pressure that is sitting over the west and central parts of the nation. The west will be dry and warm to hot this week, perhaps a weaker change passing through in dry fashion to take the temperatures down by the weekend but at this stage, from WA, through inland SA, all of the NT, much of QLD and into northern and western NSW, dry conditions are expected with a good supply of sunshine. We are seeing the pattern shift in line with the SAM with showers returning to the eastern seaboard on most modelling by day 8-10. A change also approaching WA with an inland trough may give rise to showers and storms returning.

GFS 12Z - Surface Pressure Pattern and Rainfall - Next 16 days

Refer to the video for my analysis and comparison and more on the medium term coming up later this morning.

Euro 00z - Precipitable Water Anomalies - Next 10 days

Precipitable Water values continue to be well below average today for much of the nation, note the values are set to peak well below average by mid to late week, this drier air surging north and west through the latter part of the week, bringing about a nice but hot end to dry season for the tropics. The weather is set to turn quite humid over northern and eastern areas later in the weekend into this time next week, easterly winds over QLD and northeast over NT will bring up the chances of showers and storms. Then moisture beginning to increase through the western parts of the nation thanks to a surge of moisture coming in from the Indian Ocean. Starting to see evidence of where the rainfall is likely to increase for the last week of the month.

GFS 12Z - Precipitable Water Anomalies - Next 16 days

Refer to the video for my analysis and comparison - more on this mid morning with the medium term update.

Euro 00z - Rainfall Next 10 days

Once we lose the system over the southeast tomorrow and the east coast Wednesday, the light falls will be over and the nation dry mid to late week as dry air dominates and high pressure takes over, combining to bring a rare settled spell for all states. The rainfall chances return to the southeast Friday night and Saturday with a weak front, perhaps 10mm in the wetter pockets but even that is a stretch, then the major rainfall opportunity will be through the eastern inland next week, mainly over QLD, with an inland trough combining with easterly winds and this could move south into NSW shortly after. Another trough and potential low born out of the heat trough over WA (first one of the season) could give rise to another rainfall event. Then the tropics should begin to wake up again after a nap, showers and storms redeveloping later September into the first week of October, and this should become a persistence forecast.

GFS 12Z - Rainfall Next 16 days

Refer to the video for my analysis and comparison more on this in the medium term update with the latest rainfall spread and data from GFS and other global models. Note the moisture and precipitation over QLD and NSW later in the run and through the Indian Ocean, will take a look at that and talk about what that means for you.

Southeast and East

Southwest and West.

Medium term forecast coming up later this morning and I will take a look at the wintry weather through the southeast in greater detail as well, update the frost risk for the south and east as this could be a HIGH impact event even after the cold front has skated through.



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