SA - SHOWERS DECREASING OVER THE SOUTHEAST WITH A COLD AIRMASS STILL IN PLACE.

The rainfall with the cold airmass has largely stablised overnight with a clearing sky too over inland areas and moderating winds leading to quite a cold night. Some frost patches have been observed over the north.


The drier air has filtered through much of the state though the southerly winds bring low cloud and a few showers to parts of southern and southeast SA this morning.

Mainly light falls overnight with falls of 1-8mm for many locations in the southeast.

The weather is expected to turn warmer as we track through the middle of the week as the flow becomes variable, reaching seasonal values before warming up further Thursday and Friday.

That is ahead of a stronger front emerging from WA and that front will likely form into a low pressure system over the Bight. From there the low is expected to remain slow moving until picked up by a northwest flow aloft and that may send the low southeast.


The better moisture is sitting over the eastern inland of QLD and NSW and it is expected that the weather will turn wet over the east with a upper trough there, we may end up with coastal showers for now.


The better rainfall opportunities are expected with a system emerging out of the west next week - that long wave is looking better in terms of position and may peak over the southern and the southeastern inland.


12Z GFS Surface Pressure Pattern for the coming 16 days

The low pressure system is beginning to develop offshore the NSW coast this morning, with a much colder day with wet weather over the east. The southeast will see partly cloudy cold conditions today in a southerly with that weather slowly warming up in Wednesday. There will be fine and warmer weather over in the west of the nation with a northeast flow and finally, a drier surge of weather is developing for northern parts of the NT and WA. A front will approach WA with a few showers and storms during Thursday and that system will move steadily east helping to push the pressure systems along the line to the east, including the low offshore NSW. Colder air stays trapped over the eastern inland of NSW and VIC bringing the risk of showers Friday again before a warmer Saturday and Sunday with a northwest flow. That is ahead of a low pressure system that develops out of the front which runs through the Bight. Showers may develop over SA, through VIC and NSW with this system. The most widespread rainfall over the weekend may develop through eastern QLD with an upper trough which could combine with onshore winds to bring a number of days of rainfall. That may persist through next week. A stronger system approaches the west of the nation early next week and that offers better rainfall potential for WA, SA and VIC once again in early September.

12z GFS Rainfall for the coming 16 days

Rainfall is most widespread today, we have already recorded falls over 50mm in many locations overnight. Rainfall of up to 100mm for parts of the east coast today before conditions ease on Wednesday. There will be more rainfall for eastern VIC in onshore southerly winds. Rainfall over the north today with a pulse of moisture pushing through ahead of a dry surge could drop local falls of 20mm over the northern Top End. Then the rainfall focus shifts back to WA with a front approaching the region Wednesday into Thursday. That system will move east bringing showers back through southern Australia this weekend but light falls for now. Up north the wettest part of the nation could be through eastern QLD with an upper trough triggering showers and storms later this weekend into next week. Another front approaching mid next week from WA could bring back widespread rainfall over southern and eastern Australia.


12z GFS Precipitable Water Anomalies next 16 days

You can see the moisture being absorbed into the developing low today and the dry air surging north sending the temperatures down. The dry air then takes a while to be modified across the nation. Moisture surges in from WA and through QLD later this week where the rainfall chances increase. The most widespread and deep moisture looks to be over QLD during this period and that is where we see widespread showers and storms develop over the weekend with moderate falls across a number of days. A stronger system next week may drag that moisture south and east lifting rainfall chances over the south. Then more moisture is likely to descend from the northwest Indian Ocean during the first week of September.

12z Euro Surface Pressure Pattern for the coming 10 days

The surface pressure pattern is in lock step with GFS with rain about today with a low developing over the east. That system moves away. We are then looking at a front developing over the Bight this weekend after passing through WA during the mid week. That system may bring moderate falls to WA mid week but lighter rainfall for SA. The weather turns more interesting over the east, with an upper trough over QLD possibly leading to showers and storms developing later this weekend into next week. A much stronger front over WA this time next week is the one that has the better rainfall potential for SA, VIC and NSW.

12z Euro Rainfall for the coming 10 days

Rainfall is most widespread today over the east which is well forecast and that rainfall will contract further east today. The majority of the nation from Wednesday away from the east coast is dry. The next front that passes through the SWLD may bring widespread showers and storms to the region before developing into a low pressure system bringing showers back to SA and VIC this weekend. Fine and dry weather is likely over much of the nation until this point. The rainfall then breaks out over the eastern inland of QLD with a developing trough combining with onshore winds, that may last well into next week. Then we are tracking a stronger front from WA through SA this time next week, which offers the better rainfall chances for SA, VIC and NSW.

12z Euro Precipitable Water Values next 10 days

The dry surge is moving through the nation today and that will reach the northern tropics by tomorrow clearing the first flare up of showers and storms north. Otherwise moisture redevelops over QLD in easterly winds through later this week, moisture surges in front of a developing wave moving over the SWLD and that spreads east. Then we have moisture building further throughout the nation and that looks to be lifted up by a strong cold front this time next week which offers the best rainfall chances for southern Australia post this system today.

Rainfall for the next 10 days

A few residual showers over the south of the state today with the southerly winds easing. Then we track high pressure through and it leads to fine weather for the remainder of the week. We have a cold front that is to pass throughout the SWLD with showers moving into WA, that system cuts off into a low pressure system south of the state this weekend, bringing the next chance of showers for the south. Light rainfall is expected from this. Those hanging out for more rainfall, the better chances sit at the end of the period, and I will not introduce that into the forecast just yet but note that there is something lurking mid to late next week.


I will have a climate update later this morning along with a 2 week outlook for the nation with more details on the rainfall next week.

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