The humid and unsettled weather continues after a noisy night for many in the east, north and west. The weather dominated by high humidity and low pressure wafting about.

The weather is largely unchanged for Monday. Scattered to numerous showers and thunderstorms are expected to develop during Monday afternoon and evening over QLD, NSW and the ACT with a deep trough lingering.

Scattered to numerous showers and thunderstorms are expected to form over inland WA and the NT with a deepening trough in combination of a decent moisture supply.

The tropics also remaining very active with scattered showers and thunderstorms, extending south through the outback and into the trough coming through WA.

The drier locations, VIC and SA with drier weather for now, but that won't last long as the trough moves in from WA from later Tuesday into Wednesday.

Lets take a look


Rainfall Next 10 Days

Rainfall guidance is unchanged and we have the soupy airmass draped over much of the nation with heavy additional rainfall expected over the eastern states with a trough today and then a large scale system later this week which will bring a drier surge of air across the weekend. That larger scale system may produce severe thunderstorms from southern and eastern WA through western SA and parts of the NT today, before the storms flatten into areas of rain with a few heavy falls for WA and the NT. The rainfall and thunderstorm activity continues to move east mid week, some heavy falls possible for the Ag Areas in SA and the outback as a deep low rolls through. More storms for QLD mid week dipping into northern NSW. Then Thursday and Friday the low clears from SA but brings heavy rainfall and severe thunderstorms to QLD, NSW and VIC. Scattered falls over 40mm likely as the low moves through these states. The low pops off the south coast of NSW and then clears away with an unstable southwest flow and showery weather to follow for the southeast with snowfalls developing for Alpine areas. Most of the west and central parts of the nation dries out once the low moves away to the east, taking the deep moisture with it. The tropics, unsettled but likely to see the storms contract back to the northern areas of WA and the NT this week.

Thunderstorm Forecast Monday

Thunderstorms are expected to continue from this morning into this afternoon and the evening with locally severe thunderstorms expected over northern and eastern parts of NSW, southern and central QLD extending to the coast, through the southern and central interior of WA and through southern NT. Heavy rainfall leading to flash flooding the main concern over the eastern inland of the nation with the deeper moisture layer. All modes of severe weather likely over the western interior. Some locations may see 1-2 months worth of rainfall from thunderstorms.

Flash Flood Risk - This Week.


12Z Euro - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

The pressure pattern is unchanged in terms of dominated by low pressure and very humid air. More details can be found on the day by day breakdown and looking at the passage of that low pressure system this week in greater detail. No surprises if you have been on this site for a while. The BoM have already stated in media this morning that it is related to the developing La Nina. It is actually connected to deep moisture that has been surging in from the northwest Indian Ocean infused into the low pressure system coming out of the west and the above average SSTs over the Coral Sea and the tropical waters over the north of the nation with the positive SAM. The La Nina impacts will be felt more greatly from after Christmas.

12Z Euro - Precipitable Water Anomalies - Next 10 Days

The anomalies are quite outrageous in what is a humid period for QLD and the NT, when we see blues and whites on the chart in a wet time of year, coupled with the instability, we will have trouble and flash flooding is a significant risk over the coming 5 days with waves of low pressure passing through this very moist air. Though a drier airmass will surge through the east and south from the weekend with a reduction in rainfall and thunderstorm activity.

12Z Euro - Precipitable Water Values - Next 10 Days

Near record values are being experienced this week over QLD and northern NSW with that reflected in record rainfall being observed overnight through parts of northern NSW and many areas achieving their monthly average so far. But remember some locations can still miss out on rainfall even while being humid and that occurs EVERY TIME! But the broad diagnosis is for heavy rainfall and thunderstorm activity and that is the forecast we stick with for much of this week for the east. For the west, once the low pressure moves off to the east, a drier southerly flow moves in and that will bring the temperatures down and conditions turning cooler for many southern areas in the wake of this feature. So farmers and graziers be aware of the pattern shift coming up this weekend after a period of wet and humid weather, drier and colder windy weather is expected. The tropics, staying very humid but the outback will dry out for a period before moisture returns in about 10 days time.

12Z Euro - Rainfall Accumulation - Next 10 Days

More details can be found in the video.

12Z GFS - Rainfall Accumulation - Next 10 Days

12Z CMC - Rainfall Accumulation - Next 10 Days

I will have the latest severe weather potential coming up this morning plus a look at the medium term to see how long we get a break from the rainfall, given that more rainfall is back on the cards for the end of the month.