But the southwest of the nation remains the area, escaping the humidity and rainfall, but baking in dry heat as easterly winds, which are bringing the high levels of moisture, dry out over land, and continues the Mediterranean Summer going.

For SA, the potential of severe weather developing as the moisture begins to dig in from the north of the nation and combine with a trough, that idea is becoming a higher chance with each run of the models. However, the position of the trough will dictate where the heaviest of the rainfall and the most severe weather is likely to emerge, this will refine with the coming 4 runs of data, and accordingly my charts will also refine.

Over the north, the monsoon is expected to develop over waters north of the nation. This will increase rainfall as the trough strengthens. But this feature will also add more fuel to the atmosphere already laden with moisture. Widespread rainfall over the north will translate south and east through the nation, potentially guided by tropical lows/cyclones, so that feature is something to watch.

Eastern Australia will not necessarily dry out in the atmosphere, but the airmass turns more stable with a high ridging through the region, so while sunny, it will be more like the tropics. The main trough axis sitting over SA will keep the wet weather there.

Lets take a look at the latest details.


Rainfall Next 10 Days

Rainfall remains a tricky element to forecast well ahead of time, this in part due to the position of the trough, the speed of the trough moving east, or potentially not moving at all, delivering heavy rainfall near and to the south and east of this feature. So for SA, rainfall totals will be tricky to pin down. So stay up to date. The trough is still likely to move eastwards, but it may be delayed by the firm ridge in the east, so wet weather may not arrive in VIC, NSW and the ACT until Australia Day and then into NSW and QLD with coverage after the holiday Wednesday. Up north, the monsoon trough develops and deepens over the course of this week, leading to more rainfall appearing on the charts but also in reality, with cooler weather. Tropical lows may also develop within the trough with significant rainfall located near these features, IF they form, but the chances are higher. The medium term, offering a lot of wet weather, but like the short term, low confidence on pinning down who exactly gets what in this very humid airmass. The west remains dry and stable for now, but even there, the medium term offers more rainfall chances creeping south and west.

Thunderstorm Forecast Wednesday

Thunderstorms will continue along and to the east of a trough through the NT, stretching through QLD and into NSW with the remnants of Tiffany leading to deep moisture levels and the chance of heavy rainfall leading to flash flooding. Up north, the risk of damaging winds is possible in the NT and through outback areas. High based storms possible about a seabreeze front during Wednesday afternoon in the northwest of WA.

Thunderstorm Forecast Thursday

Thunderstorms are expected to continue through the central interior and through to the eastern inland in a moist and unstable airmass. Heavy rainfall from thunderstorms could lead to flash flooding in the Central NT and through western QLD and eastern WA. Thunderstorms may also develop along a new trough sharpening through central SA through to the Agricultural areas, with gusty winds and moderate rainfall.

Thunderstorm Forecast Friday

Thunderstorms will continue overnight for SA into Thursday with severe weather possible, all modes of severe weather also possible, heavy rainfall leading to flash flooding the big concern. Thunderstorms over the tropics may see gusty winds develop inland of the coast.

Tropical Depression Watch - January 20th-27th 2022

Tropical depression may form as early as Thursday up over northern parts of the Arafura Sea and track southwards. The upper level winds and SSTs are favourable for development into a cyclone, but it needs to stay over water and avoid the island chains north of the nation. One way or the other, enhanced rainfall later this week over northern Australia is likely with a developing low off the Kimberly Coast by the weekend.

Severe Thunderstorm Risk - January 22nd-28th 2022

A deep trough over the central parts of SA is expected to form during Friday and across the weekend, deepening further, pulling in high levels of moisture with the risk of severe thunderstorms over a number of days. Storms will carry the risk of heavy rainfall leading to flash flooding and damaging winds. Hail is a moderate risk. Thunderstorms will progress towards the east during over the course of next week and Australia Day.

DATA - Refer to video for more information where I look at GFS.

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

No real change to the guidance last night, very good agreement on placement of the severe weather and rainfall associated with troughs through northern, central and eastern parts of the nation, the timing of that weather and the scale of that weather. What will chop and change is the specific rainfall amounts you are seeing on your apps, throw the apps out in these situations, the data on specific rainfall and temperatures are useless (especially the deterministic data). The trend is what you are looking for, and that trend has not altered that much from overnight.

Euro 12Z - Precipitable Water Values - Next 10 Days

The PW values remain exceptionally high for much of the north and east, with that very humid air extending into SA from tomorrow and remaining in place for a number of days. This higher PW will lead to higher and near record rainfall for outback areas of the nation, especially near the trough over SA and into the NT. The moisture will eventually spill over the eastern side of the country as the ridge keeping things settled for a number of days, begins to relax and falls away to the southeast. This looks to occur from the weekend. Over the north a monsoon trough will continue to pass over northern Australia with a tropical low or two possibly developing throughout the trough. That will lead to heavy rainfall. Drier air stays in place over SW WA.

Euro 12Z - Rainfall Accumulation - Next 10 Days

More information in the video

GFS 12Z - Rainfall Accumulation - Next 10 Days

More information in the video

CMC 12Z - Rainfall Accumulation - Next 10 Days

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Euro 12Z - Rainfall Accumulation - Next 15 Days

More information in the video

GFS 12Z - Rainfall Accumulation - Next 16 Days

More information in the video

I will take a look at the severe weather potential sweeping the nation in greater detail later this morning and a look at the monsoon potential.

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