EVENING WEATHER UPDATE - THE STORM EVENT BEGINS FOR THE EAST - RAIN AND STORMS FOR THE NORTH.

And you know the drill if you are living out west, hot and dry with easterly winds, SA sitting in the subsidence or sinking air motion, warm and dry for a number of days for your region.


For the remainder, no real significant shift in the guidance for where the active severe weather will be and where the cooler and wetter will be either.


As pointed out this morning, we are tracking a number of dynamic days of weather and some areas I am afraid will be belted by significant rainfall and flooding issues, some areas also expected to see riverine flooding for a number of days following the event.


The north of the nation, routine weather for now, but signals for a monsoonal burst growing and developing from mid month onwards which will draw additional moisture across the nation and into the southeast and east. Areas out west will also start to pick up on higher rainfall chances as we move into the second half of January as forecast here for many weeks now.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall still fairly heavy and widespread in the short term with a decent supply of moisture running from north to south into a trough coming into the eastern inland of NSW through VIC producing severe weather potential. We have another port of moisture sitting over the northern tropics near a heat low and trough producing scattered to numerous showers and thunderstorms once again during the coming days, as per the tropical rainfall guide, near impossible to draw how much rainfall you will see up there, but some places could see 70-120mm per day with large thunderstorms. Beyond these two features in the short term the area to watch coming into next week will be the developing tropical lows across the north embedded within the trough. With tropical waves passing through, each of these will need to be watched for development into cyclone activity. The higher chances still exist for the Coral Sea, over Cape York and across the Top End, lesser risks for the Kimberly and Northwest. Any cyclone that forms, crosses the coast and then gets pulled south or southeast into the mid latitude westerly flow will clearly form major rainfall events across Australia, there is a very high risk of this occurring, but a very low confidence in predicting where.

Thunderstorm Forecast Wednesday

Showers and thunderstorms become more widespread during Wednesday with storms tending severe with heavy rainfall leading to flash flooding the main concern. The storm coverage over the north and northwest also on the increase with storms tending severe, gusty damaging straight line winds are possible. Thunderstorms may also produce heavy rainfall.

Thunderstorm Forecast Thursday

The trough over the east amplifies in response to the approach of an upper feature from SA and the absorption of Seth in the east so widespread showers and thunderstorms with heavy rainfall leading to flash flooding the main concern. Thunderstorms extend through inland QLD, though more scattered, may be gusty and heavy also. For the northern tropics, the thunderstorms will likely trend more gusty once again during the afternoon and evening with dry high based storms extending southwest from the tropics into the Pilbara.

Thunderstorm Forecast Friday

Thunderstorms continue for the same areas into Friday with severe weather continuing over the east and southeast with the trough stationary. Heavy rainfall leading to flash flooding and damaging winds are the main issues. The highest risk once again over inland areas of NSW and VIC. The storm coverage over the north remaining unchanged with a deep trough developing over the northern states. The trough will snake back into WA with a chance of gusty storms but mainly light rainfall totals for now through to the Pilbara and Gascoyne.

SEVERE THUNDERSTORM OUTBREAKS TO WATCH

This is the last of the severe thunderstorm watch area for the period, but this chart could be reposted once again for later in the week and into the weekend with another surge of energy coming through in conjunction with a tropical wave, so while we move back to routine weather, the severe weather threat may reemerge over the weekend into next week.

SEVERE THUNDERSTORM OUTBREAK - OVERALL THREAT WEDNESDAY THROUGH FRIDAY.

Thunderstorms are likely to increase from Wednesday but more likely Thursday and Friday with areas of heavy rainfall leading to flash flooding the main concern. This area of thunderstorm activity will remain in place until Friday as the trough slowly moves through and multiple waves of storms are likely to form in this region during this period. So remain weather aware, especially in areas that have seen flooding previously.

Tropical Depression Risk - January 10-17th 2021

There is a heightened risk of tropical activity across northern Australia throughout the next week. This will lead to enhanced rainfall risks near any low pressure that forms, and this will then feed troughs over the nation seeing rainfall increase over central and eastern parts of the nation primarily. However, a tropical low that runs further west of the modelling, may bring up rainfall chances for areas over WA and SA. Currently models are split on where the tropical low/lows form and which one becomes the dominant feature, so this the issue with the longer term forecasts, and trying to pin down who gets exactly what out of that, in terms of impact from the cyclone and then offshoot moisture is generally very poor. I will update this chart again on Wednesday.

DATA - Refer to the video for more information


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

From three tropical cyclones to one now, over the opposite side of the nation. As mentioned over the past week, the bogus TC game play continues on the models, this suggesting a more active tropics and more moisture working it's way south in the coming weeks. In the short term, we have significant rainfall for the southeast which could cause some issues.

00Z CMC - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

Note the difference in the pattern over northern Australia between the two models. This is the low confidence guidance I have been referring to of late and it will continue.

00Z GFS - Precipitable Water Values - Next 16 Days

The moisture content throughout the nation's north and east remains elevated for the best part of this period and the drier air stays in place for most of SA and WA throughout this period, so the pattern refusing to flip if this is right, however I would be very shocked if we do not see SA and WA begin to pick up some rainfall and higher humidity into mid to late month.

00Z GFS - Rainfall Accumulation - Next 16 Days

More information in the video.

Another update coming your way tomorrow from 8am EDT. The modelling is still quite poor so no point in the rainfall wrap this evening, with terrible divergence continuing.