The weather settled for the most part into the weekend as a ridge and dry air remains over the inland, but as we can see today, there is a sliver of unstable air ahead of the dry and cold surge moving through the southeast and eastern inland leading to a few showers and thunderstorms. That trough will remain in place over the eastern areas of the state into the weekend with a few showers and storms persisting, but the remainder of the state settled with increasing humidity.

That will lead to cloud increasing across the state with isolated to scattered showers breaking out from later Saturday in the north and then extending south on Sunday with that rainfall coverage becoming more widespread and heavier as the moisture sweeps into the state from the northeast flow.

As the upper trough develops from the NT and SA and continues to slowly evolve into low pressure system, this will bring more widespread heavy rainfall over the inland areas via thunderstorms. I say heavy in comparison to seasonal averages, some areas could see falls well over the average for May during this period, continuing the highlight the influence of La Niña, this being forecast here for a number of months now so it should be no surprise.

The upper low that forms will invigorate a trough along the coast, and this will lead to widespread heavy rainfall along sections of the coast as well, leading to a broad flood risk once again along the coast and inland of the state.

As we move through next week, the upper low is forecast to remain slow moving leading to areas of rain and thunderstorms but the coverage of rainfall will begin to sweep eastwards as the drier air gets pulled in from the south into the western flank of the low-pressure system.

So, with the slow movement of the low-pressure system and deep moisture in place, this will be a multi-day rainfall event. The rain will ease eventually by next weekend, but it may not totally clear the east of the state.

Let's take a look


Rainfall Next 10 Days

Rainfall is set to continue over the southeast of the state tonight along a stalled boundary. This boundary is forecast to meander near the coast through the weekend with showers persisting for some communities along the coast and a thunderstorm may be possible for some adjacent inland areas. The upper low over the western interior begins to kick off showers and storms from Sunday through many districts as moisture feeds into the system from the north and east. By Tuesday into Thursday, widespread rain and thunderstorms should cover a good chunk of the state with heavy falls about. Showers along the coast also increasing as a trough moves inland from the coast, with that system possibly leading to a flood risk increasing during next week for coastal areas. The rain and thunderstorms over the inland will slowly move east with the passage of the upper low during next week. The position, scale, depth and speed of the low will determine the rainfall coverage whichn remains to be seen so understand, your rainfall numbers on modelling and forecast packages will be somewhat different from run to run but the idea is the same, widespread rainfall is forecast to move across the state with a flood risk.

Severe Weather Risk - Tuesday through Friday

A deepening upper trough which will likely cut off into an upper low will combine with deep moisture to produce widespread rainfall, some heavy through the inland with the risk of riverine and flash flooding. A separate trough over the coastal areas between Cardwell to Hervey Bay may trigger torrential rainfall through this period but the confidence is not high.

Flood Risk - Next Week

The flood risk is expected to increase through the middle to latter part of next week, especially the closer you are to the coast between Ayr and Bundaberg along the coast. A low to moderate risk extends well inland and will be connected to where heavy thunderstorms emerge.

MEDIUM TERM - May 12th-19th 2022

Rainfall Anomalies

With the bulk of the heavy rainfall event with the upper low now moving into the short-term forecast, the anomalies are looking less dramatic for the east though lingering heavy rainfall early in this period will continue for the east before easing and clearing. The north of the nation likely to see further above average rainfall potential with the SAM remaining positive sending in more humid northeast winds. Over in the west, the rainfall should be leaning above average through this period with the long wave trough settled over the region if not offshore producing cold and showery weather. Most elsewhere should be seasonal with a mixture of rainy days but mild sunny days too.

Temperature Anomalies

The cooler bias is unchanged over in the west with the persistent onshore flow with windy weather and showery conditions. The east warms up following the widespread high impact rainfall event. With the winds out of the northwest in advance of cold fronts and a ridge to the southeast and east of the nation, a warm tongue of air could become established over the north and east for a good chunk of this period.

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 information can be found in the video at the top of the page to cut down on your reading but overall, the cold outbreak continues to work through the southeast inland of the nation. The dry and warm weather over the west and north will continue through the weekend. A few showers and storms may also continue for parts of eastern and southeast QLD before an upper trough approaches from the west of QLD and that will lead to increasing rainfall and the high moisture levels will be utilised into widespread rainfall with heavy falls through next week with severe weather potential. Over in the west, a strong cold front also needs to be watched with severe weather potential with heavy rainfall and strong winds. That feature to become better modelled by the weekend. The medium term offers more frontal weather over the south and more humidity for the north and east. So the mechanics and ingredients for further severe weather is possibl

00Z GFS - Precipitable Water Values - Next 2 Weeks

The moisture content is somewhat below average over the southeast and southern parts of the nation thanks to a broad cold outbreak that is continuing to unfold across the region. The cold and dry air will stop short of moving into QLD but it will move through the remainder of the country. The moisture is forecast to deepen further this weekend over the northeast and this moisture will spread south and west overriding the drier air in place at the moment leading to elevated rainfall. The moisture will then spread through much of the south and southeast lifting rainfall chances next week for QLD, NSW and the ACT. The next pulse of deep moisture is forecast over the SWLD of WA leading to higher rainfall chances next week. Some of that moisture could make it across to southern parts of SA and then into the southeast. Moisture also creeping up over the northern tropics as well through next week and into the medium term and we have another shot of moisture coming into the jet stream from the medium term as well over WA which will too spread eastwards.

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 is to be highly variable from model to model and run to run and this won't settle down for a few days so expect more changes to come and refer to the broader updates here for understanding and analysis while we wait for more consistent data.

I am travelling tomorrow morning early to Darwin and will have the next video at some stage tomorrow. There will be weather information throughout the day so look out for that plus a climate refresher. Have a great evening!

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