SA - RAIN CLEARS EAST TONIGHT. WARMING UP AHEAD OF MORE RAIN FRIDAY. MAYBE MORE NEXT WEEK.

The active weather starting to unfold as advertised here some months back, after a relatively quiet start to Autumn, conditions would start to shift with rainfall chances increasing as we move into the seasonal change, and unlike last year, this year's rainfall for those who have had it, much heavier.


As one rain event moves east, the weather will start to warm up and dry out as a weak ridge pushes into the state. But with the next rainfall event knocking on the door, the airmass cannot quite dry out, as we are looking at the next front slamming into deep moisture leading to another fairly decent cloud band forming right on top of the state.


Timing is everything, and the timing of the front is forecast to favour heavier rainfall developing with storms over eastern areas of the state, so bypassing much of the Eyre Peninsula, getting it's act together from about the Mid North but bringing more persistent rainfall over the eastern areas bordering Victoria and NSW.


The front may develop into a low as it passes into the southeast which could enhance rainfall over the eastern and southeast areas but that is a low confidence forecast right now.


Moving into the weekend proper and things dry out. We will still have jet stream cloud moving over northern and eastern districts with a little rain but the bulk of the wet weather should be gone.


Another upper level disturbance is forecast to emerge from the south next week and as the flow turns easterly once again across the nation, we may have a similar rainfall event to the one previously experienced, where inland falls become excessive and spread south and east ahead of the next cold front.


So a very busy period coming up.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall is forecast to be heaviest in the far east tonight but should clear by morning. A few showers may remain in random pockets of the inland tomorrow and Thursday. A warmer and more humid airmass will establish itself ahead of the next front that is due in by Friday. It will bring a chance of a batch of showers and storms, some strong to severe if the front is delayed a little and can move through during the peak of the daytime heating process. Now that system should move through fairly swiftly into the eastern inland of the nation leading to drier weather developing across the state by the weekend with the chance of a few showers over northern districts. The weather may turn more humid again next week with the chance of a few showers and thunderstorms returning next week, an upper low may form over the state resulting in the next rain event unfolding once again for northern and eastern areas. It could bypass the southeast and southern areas, but it is a week out and we must watch trends closely.

Southeast Areas

Rainfall is forecast to return during Friday afternoon along a cold front bringing showers and gusty winds. There may be some strong to severe storms over the Upper Northeast with heavy rainfall and damaging winds a risk.

Yorke and Eyre Peninsula

The rainfall likely to return for the region from Friday with a front approaching. Scattered showers and thunderstorms from the morning increasing the further east you are where the dynamics and moisture are more supportive of widespread activity. Storms may be severe.

Severe Weather Watch Friday

The risk is mainly for Friday before moving into the east on Saturday. Thunderstorms could turn severe with gusty winds and heavy rainfall for mainly eastern areas of the state.

MEDIUM TERM - May 4th- 11th 2022

Rainfall Anomalies

Rainfall signals remain above average for large areas of the north and east as well as pockets of the southeast and southern inland of the nation. Moisture persisting over the tropics likely being drawn into the jet stream will be lifted by areas of low pressure through the nation leading to above average rainfall. This pattern has been repeated time and time again this year and we are likely to see more of this occurring. A cloud band developing over northwest WA is possible if we see a tropical incursion approach the northwest of the country.

Temperature Anomalies

Not much change from yesterday with the cooler and drier air over the southwest leading to the below average temperature smear. Over the northern tropics, the above average humidity values will lead to above average temperatures during the days and nights with the above average rainfall signal. The east, higher humidity should keep things relatively seasonal, but wet and humid.

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


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

More details in the video but we are staring down the current rainfall event in the east, a rainfall event to come over the weekend through southeast and eastern parts of the country with a cold front running into the moisture. Deep moisture to return next week lifting the chances of follow up rainfall for the southeast inland of QLD and northeast inland of NSW. More rainfall could emerge for SA with an upper system next week. The rainfall over the tropics also tending above normal for this time of year and that could run through the northwestern interior with above average rainfall chances as well. The southwest will be dealing with cold fronts and the possibility of moisture being drawn into the westerly wind belt from the Indian Ocean into the medium term.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The values are anomalous over the east and that has lead to the excessive rainfall of recent days, but you can see the moisture easing in intensity over the next week. But further moisture may be drawn in from the northeast and north of the nation southwards next week into another upper level system. This could set the scene for widespread follow up rainfall. The tropics could be covered in very high moisture content into dry season leading to more above average rainfall. That moisture if it gets to the northwest of the country, could be propelled south and southeast through the nation via the jet stream.

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 tricky to forecast for SA with this next system over the course of Friday, where it peaks determines the spread of rainfall, but it does appear to be further east. More chances of rainfall developing next week with another upper system.

More coming up from 8am EST tomorrow. Have a great night.

47 views2 comments