NATIONAL WEATHER WRAP - SATURDAY 7TH OF AUGUST 2021

HEADLINES


  • The west of the nation turns wet today as the east slowly clears. A sharp cold snap expected in the coming days for WA.

  • The gloomy skies over the eastern inland gradually improving today but the coastal areas of VIC and SA will have to wait until Sunday.

  • Warm and sunny over QLD, temperatures set to rise through most of the southeast and eastern inland next week with a cold front approaching.

  • Dry season continues over the northern tropics for a few more days before the humidity starts to rebuild.

The weather is benign if you are living away from WA. A chance for a breather after what has been a very active 5-6 weeks. I certainly have enjoyed the quieter weather. But it will not last long, so make the most of the drier period before things ramp up again from mid month onwards.


National Satellite

Clear skies across most of the country, though there is still a blanket of stubborn low cloud west of the divide through southern and central NSW. The cloudy skies also engulf much of VIC and southeast SA today, but conditions should start to improve from this afternoon. A cold front, the first of four to move through SWLD of WA is approaching with a moisture in feed as well, thick middle level cloud is impacting parts of the coast there. Winds will turn into the southeast today and start to sling that low cloud offshore NSW onto the coast.

Temperatures as of 7am

Cold starts through the southeast under clear skies, but where the cloud has lingered overnight, it has been milder with not much movement in the day time and overnight temperatures in recent days. Fine weather and clear skies also bringing a cold night to parts of QLD and the NT. Warmer over the northwest and west with humid air and warm northwest winds, only down to 21C at Exmouth this morning.

Colder starts in the eastern shadow of the GDR, frost has been widespread from Cooma through to Bathurst this morning with some locations down to -5C. Travel to the west of the divide and you increase by 10-15C from those lows.

Rainfall for the next 10 days

It is a benign week of weather for most in comparison to the previous 6 weeks. That is not always a bad thing, but if you want rainfall through the southeast, mainly light falls expected. However there is a pocket of heavier rainfall expected down through southeast NSW towards the ACT as the front links up with moisture coming southwest from QLD and northern NSW. That will lift the rainfall totals through a pocket of southeast NSW, especially over the GDR. Light falls for VIC and SA, though where the front crashes onshore over southeast SA there could be some falls towards 15mm this week. The southwest coast is wet this week, multiple fronts though they are not carrying as much moisture as the previous events, so moderate rainfall for each front as the pass through, clearing later in the week. The east coast likely to become the wettest part of the nation, for FNQ and areas exposed to the southeast to easterly winds, some locations easily clearing 40mm in the coming 10 days.

12Z GFS Rainfall next 16 days

Rainfall guide from GFS remains low confidence in the medium term, but for the short term has the widespread showers along the east coast in two waves, one that come through early in the week and another later in the week as high pressure cells move to the south of the region freshening the easterly winds. One system to come through southern Australia will link up with that moisture from the east and see rainfall turn moderate over the southeast of NSW. Showery over the southwest this week will net 40-60mm in some areas of the SWLD and 10-20mm for the west coast. Then the medium term, moisture starting to pool over inland areas of the nation but as I keep saying from run to run, it keeps shifting where the rainfall ignites. This time it has another rain event for NSW.

12Z Euro Rainfall for next 10 days

Euro for the next 10 days is a lot drier than the GFS and has less rainfall nationwide away from the SWLD of WA. Still, expect showers for the east coast early and later this week as high pressure rolls through, the front to escape WA and brings a band of showers of the SE States and then moisture rolls back in over WA next weekend with another front.

12z CMC Rainfall for the next 10 days

Similar to the other global models but not quite picking up the frontal weather well and the shift to the high pressure dominating the nation, it usually lags behind the main global models used, but you can see a similar spread over the coming 10 days. A bit more moisture for the eastern inland of QLD.

12z KMA Rainfall for the next 12 days

This model has deeper moisture settling over WA in the medium term with widespread rainfall at the beginning and end of the run. Showers for the east coast, not as robust as the other models above. Showers through the southeast mid week, heaviest over the Alpine areas and southeast NSW. Dry elsewhere.

12z GFS Upper Level Pressure Pattern next 16 days

I have not used this product for a while, but you can see the stark difference as the pattern flips over the coming 4 days. The dominance of the colder upper levels, gone. The high pressure moving in, a return to easterly winds over the east coast. Weak upper troughs lurking over northern Australia, instead of the bulky upper high. Cold fronts are further south. Now we will start to see the pattern play out with that moisture increasing in the next week and then the shorter term global models picking up on that signal and starting to introduce more rainfall into the outlook. This is an encouraging sign for those wanting more rainfall, warmer weather for feed to grow and less frosts!

12Z GFS Surface Pressure Pattern next 16 days

The surface pressure pattern really highlights the dominance now of that sub tropical ridge of high pressure moving south, setting up camp over the southern states, allowing easterly winds to develop for QLD and the northern parts of the nation. This is where will see the moisture values increase markedly in the coming week and perhaps play out with widespread rainfall for the second half of August for inland parts. We wait and see where that kicks off! WA still the front runner for moisture to be lifted into widespread rainfall first.

12Z GFS Precipitable Water Values next 16 days

PW values of 20-30mm coming into WA today can be seen reflected in the thick middle level cloud developing ahead of the front moving east. Rainfall, moderate at times, developing for the coastal regions between Geraldton and Exmouth today. The moisture will return to the northern and eastern inland of the nation from mid week, the cold front from WA running into a surge of that moisture heading south, hence why the rainfall increases over southeast NSW and bypasses VIC and SA. The medium term has a deeper moisture profile over much of the north of the nation, being dammed by a large belt of high pressure. The longer it builds into the outlook, the better it will be for the rain event that develops over inland areas. in the second half of the month. Note the moisture continues for the eastern parts of QLD and NSW in onshore winds.

Another update this afternoon. Enjoy you Saturday.


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