The overall confidence in forecasting is low - not uncommon for Spring and especially when we have a high amplitude meridional pattern (north-south movement of weather). This pattern is expected to persist for at least another week before a more zonal pattern returns.
So lets take a look at the latest data and see if we can get some questions answered.
Moisture Watch This Week - October 22-29 2021
Most models are unchanged in the coming week in terms of moisture distribution. As you can see in the video, the GFS keeps the moisture out of the eastern inland, with an upper ridge/high over the region. The moisture circulating on the periphery of this system. The tropics very humid and that air moving south and become stagnant over central and northwest parts of the nation leading to above average rainfall chances. The east humid with easterly winds. A weak front today through Saturday bringing moisture through southern areas of Australia.
Moisture Watch Next Week - October 30-November 6 2021
And even in the medium term, the moisture still being analysed similar to yesterday across models, but the issues comes down to where the lifting mechanisms are to see the rain and thunderstorms develop. This will become clearer and change by the time we get to next week so watch your forecasts closely.
Rainfall This Week - October 22-29 2021
Dry over the central eastern inland with an upper high and over the northwest interior of WA with dry air dominating these regions. You can find the rainfall on the periphery of the upper high through northern and eastern Australia. The moisture will be up against it as it tries to move southeast and east over the course of this week, but some models are more aggressive than others when it comes to rainfall potential later next week for SA, VIC and NSW. The southwest of the nation will see reasonable shower coverage early in the week with a cold front passing through Monday. The tropics very wet and unsettled with that above average rainfall threat spreading south through the NT and eastern WA. The east coast showery with storms inland over northeast NSW and southeast and central QLD.
Rainfall Next Week - October 30-November 6 2021
Moisture continues to pool over the NT with widespread showers and thunderstorms leading to above average rainfall potential. The forecast confidence for the remainder of the nation is low confidence so as mentioned in the video, pay attention to the forecasts over the next 4-5 days and still prepare for major changes to these outlooks with the guidance at the moment quite poor.
Rainfall Anomalies - October 22-November 6 2021
Rainfall anomalies are expected to remain neutral for much of the southeast even though we see some models showing not much, the confidence is poor. The higher confidence in rainfall being above average is over northern and central parts of the nation and the east coast. The southwest could see another round of rainfall but falls not exceeding the average, however rainfall this week for some parts of SWLD of WA could tip some locations into new records in terms of October rainfall which is incredible.
Temperature Anomalies This Week - October 22-29 2021
No change to the guidance through this period with the warmer weather being felt today for much of the nation. The northern flanks of cold fronts will be injecting cooler air over southwest and southeast portions of the nation from time to time, but inland areas are remaining warmer than normal. The conditions over the north remaining hot but there is a shift coming.
Temperature Anomalies Next Week - October 30-November 6 2021
The pattern is likely to flip, a flat ridge over the southern parts of the nation will keep the warmer weather over southern portions of he nation but with the copious amounts of rainfall and cloud cover forecast, temperatures coming down! That is a sign of the pattern shifting to the wetter and stormier phase as we go through the next 6 weeks.
DATA - More details in the video.
18Z GFS Surface Pressure Pattern and Rainfall Distribution - Next 16 Days
18z GFS Precipitable Water Anomalies - Next 16 Days
18z GFS Rainfall Accumulation - Next 16 days
12z CMC Rainfall Accumulation - Next 15 days - MODERATE CHANCE.
12z Euro Rainfall Accumulation - Next 15 days - MODERATE CHANCE
12z GFS Rainfall Accumulation - Next 15 days - LOW CHANCE
I will have your state based forecasts this evening. Have a great afternoon.