MEDIUM TERM FORECAST - THE WILD WEATHER POTENTIAL PERSISTS.

The rain and storms experienced over eastern and northern parts of the nation is taste of what is to come over the coming 10-14 days as many head into Harvest 2021. This should not come as a surprise as with the Harvest Outlook Forecasts since August have been suggesting this wild weather potential and now we are seeing that verifying.


The biggest feature across the nation is the high humidity values and moisture content throughout the nation with record humidity values resulting in record rainfall potential for some locations.


Two upper low pressure systems, one over the southwest of WA and another over the southeast of the nation next week pose significant weather risks. Both rather anomalous and these anomalous systems are going to be rotating through some record humidity values, the recipe for some absolutely wild weather. Now the position, scale, timing and depth of these features needs to be ironed out, BUT I need to flag this threat as many are looking at crops in the ground waiting to be harvested.


I really hope the models settle on a solution and also settle down as we move through the coming days, we will have a better handle on that by Sunday.


For now the persistence forecast remains, showers and thunderstorms for most areas of the nation, the wetter states being over the northern and eastern areas, but we are now seeing pockets of the west seeing another round of rainfall, with above average rainfall over the SWLD too as well as Ag Areas of SA on some modelling.


Lets take a look

FORECAST

Moisture Watch This Week - November 4-11 2021

We have already seen the impact of the first major impulse of moisture escape the north of the nation and find a trough bringing rain and thunderstorms through large portions of Australia with many areas copping a clobbering. This humidity is not going anywhere and we have another impulse heading south and east through SA tomorrow and into VIC Friday night into Saturday bringing up rainfall chances for the eastern inland this weekend and next week combining with the left over moisture in place at this time. The north recording humidity values will shift south into WA which could lead to record rainfall. That will seed the third trough at the end of this period.

Moisture Watch Next Week - November 12-19 2021

The third trough and deep moisture profile will continue to move east while another deep low in the southeast will draw more moisture south and east through NSW and QLD with a high chance of heavy rainfall developing with thunderstorms. The tropics continue to see excessive humidity values persist through to the end of this period.

Wild Card Systems - November 11-19 2021

The weather is expected to be dynamic and highly unstable throughout the medium term with a significant risk of large scale rain and thunderstorm activity over QLD, NSW and VIC. The risk is lower for SA but will watch trends. The weather over the southwest will ease as the trough and low pressure system moves eastwards. However this likely to be another impulse of moisture coming through northwest of Australia and spreading into a trough bringing more rain and thunderstorm activity around the 18-19th of November.

Rainfall This Week - November 4-11 2021

Heavy rainfall observed over the southeast, eastern and central as well as northern Australia will continue this week with high levels of moisture and deeper instability values moving throughout the nation. The rainfall is likely to lead to flash flooding, especially with thunderstorm activity through most states. The weather over the southwest of WA remains dry until this time next week when the humidity and an upper trough brings rain and thunderstorm activity into the region.

Rainfall Next Week - November 12-19 2021

The wild weather continues into mid month with the upper level system over WA and another upper level system over the southeast driving rain and thunderstorms, with further heavy falls. The central interior could be very wet with more record rainfall chances and this will eventually spill into QLD as everything eventually moves eastwards as a high nudges eastwards around the 18-19th.

Rainfall Anomalies - November 4-19 2021

Well above average rainfall has been observed through this period so far and will continue from northwest through southeast and east during this period before we may see conditions ease from around the 18-19th.

Temperature Anomalies This Week - November 4-11 2021

The humid and warm weather in the east will be back this weekend before the weather turns cooler with thicker cloud cover and more rainfall emerging from the central interior. A cold pool of air over the southeast may bring temperatures down over VIC and SA if that verifies later next week. The warmer weather over the northern parts of Australia starting to ease with the rainfall frequency and coverage expanding and increasing.

Temperature Anomalies Next Week - November 12-19 2021

Widespread cloud cover with rainfall over the eastern 2/3rds of the nation will continue to move eastwards but the impact on temperatures will be rather elevated, with below average temperatures to persist for large parts of the inland. Those temperatures may begin to recover to seasonal from the west after this period for the last week of November with perhaps warmer weather available for western areas spreading east.

DATA - Refer to video for more details on the below.


18Z GFS Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

18z GFS Precipitable Water Anomalies - Next 16 Days

12z GFS Rainfall Accumulation - Next 16 days

12z CMC Rainfall Accumulation - Next 15 days

12z Euro Rainfall Accumulation - Next 15 days

Be weather aware in the coming days with the severe weather risks and the elevated chances of thunderstorms and flash flooding bringing record rainfall to scattered pockets of northern and eastern Australia.