NSW - SHOWERS AND STORMS INCREASING FOR THE STATE TUESDAY AND LATER THIS WEEK.

The severe weather up north continues, but the stagnant pressure pattern and onshore winds, troughs in our region is set to provide us with another set of stormy days, maybe not as wet as last week, but the storms will equally pack a punch where they form with all modes of severe weather possible.


For the far west, remaining mostly dry for now, but the coverage of storms will be placed a little further west than the last event so perhaps some areas picking up on rainfall for the first time in a few weeks.


In the medium term, the remains of Tiffany over the north will dictate the weather, so broadly speaking remaining unsettled for the east, but how wet it becomes over NSW in relation to the tropical influence remains to be seen. There are some solutions that are drier, but many are a lot wetter than what is publicly available. So just be prepared for your forecasts to change quite dramatically as we move along in the coming 5-7 days.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall remains very much hit and miss, more so than last week when we saw the trough in the east produce widespread areas of rain, thanks to more dynamic support in the form of an upper low. This system will be surface based with atmospheric waves rolling over the top so more showers and storms in fits and bursts rather than broadscale rainfall. So keep that in mind, your number will vary. As we go further along into the medium term, there may be more widespread rainfall developing for the east coast of the nation and through much of eastern and central NSW depending on the pressure pattern, but confidence remains low at this point. One way or the other it is not looking dry, it is a matter of how wet does the weather turn in relation to the tropical moisture floating around up north.

Thunderstorm Forecast Tuesday

Thunderstorms are likely to be back during the afternoon and evening, and likely to turn severe in pockets over the Great Dividing Range and points west. Storms will carry the risk of heavy rainfall leading to flash flooding, damaging winds and a lower chance of larger hail in the stronger storms. These storms will move swiftly to the northeast and east so a good coverage is expected across the state.

Flash Flood Risk Tuesday

With the high moisture levels in place, thunderstorms will have the capacity to produce localised bursts of rainfall in the order of 30-50mm/hr with some places likely to respond quicker than others to flash flooding so just be weather aware tomorrow especially through southern and southeast NSW where storms have already dropped 2-3 months worth of rainfall in some locations.

Damaging Winds Risk Tuesday

With strong winds aloft and a good chance of heavier precipitation, damaging winds are a good chance across the southern and central plains during the afternoon and evening, making the Great Dividing Range later. The higher risk is on and west of the divide.

Large Hail Risk Tuesday

There is a low to moderate risk of large hail developing with the stronger multicellular storms that pop up during the afternoon and evening. Storms may carry hail in excess of 3cm. Maybe isolated stones in excess of 5cm with any supercells that form but the risk is low.

DATA - More details on the GFS and CMC guide in the video.


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

This is a low confidence forecast as we work out where the steering currents take Tiffany and ultimately that will drive the weather nationally as mentioned throughout the day.

00Z GFS - Precipitable Water Values - Next 16 Days

The deep moisture profile is something that all models have in place but the difficulty will be in teaming the deep moisture with adequate areas of low pressure, where does the tropical system go? Many of these parameters need to be answered before your rainfall and temperature forecasts will carry more confidence. So keep that in mind.

00Z GFS - Rainfall Accumulation - Next 10 Days

More details can be found in the video.

00Z CMC - Rainfall Accumulation - Next 10 Days

This is the more plausible solution and more details can be found in the video.

00Z GFS - Rainfall Accumulation - Next 16 Days

I am leaning away from this solution, but note that this will change a lot in the coming days and your number will change constantly. The drier areas will be the west and south, the wetter areas will be north and east.

A closer look in - note that I am siding with other models, but this gives you an idea of what is on the table as we move through the remainder of the month.

More details coming up tonight on all things models and rainfall from about 9pm EDT.




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