NSW - SHOWERS AND STORMS TUESDAY - WIDESPREAD RAIN WEDNESDAY.

A wet phase about to unfold through the state with a deep moisture supply coupled with a strong trough with dynamic forcing aloft, this will set the stage for an outbreak of spring thunderstorms. The chance of thunderstorms turning severe is low on Tuesday as the air is marginally unstable but this changes during Wednesday and Thursday.


Widespread rainfall with locally heavy falls are expected too, so lets get straight into it.

Rainfall for the next 10 days

Rainfall guide for the region is quite significant with a multiday rainfall event underway from Tuesday and persisting through until later this week. Thunderstorms are key to areas clearing 50mm along the divide (the area is broad but your number will vary from place to place!). Some areas over the Southwest Slopes could record 100mm of rainfall before the weekend arrives. Flooding obviously a concern for those regions and along and west of the divide. More rainfall is possible later in the weekend with another system passing through from the west but the dynamics not as robust with that feature at this time but needs watching.

Central West Region

Northwest NSW

Southeast NSW

Southwest NSW

Thunderstorm Forecast Tuesday

Thunderstorms are likely to develop during the afternoon and evening with some storms strong with gusty winds and heavy rainfall but they will all most likely be below severe thresholds. The storms will advance towards the GDR range in the southeast with the storms weakening the further east they travel, thanks to the dynamic support being further west. This changes Wednesday.

Flash Flood Risk Tuesday

Flash flooding is a low chance with thunderstorms over the inland and mainly confined to the peak of the daytime heating process. The risk increases Wednesday and Thursday.

Damaging Winds Risk Tuesday

A low end risk of damaging wind gusts on Tuesday hence the severe thunderstorm risk is less than 10% but you have to expect the unexpected during storm season.

Riverine Flood Risk Wednesday through Saturday

The flood risk is elevated for those communities on and west of the divide and particularly in catchments that have been under flood watch and warning in recent weeks and or months. The weather is expected to be supportive of more flooding developing in areas that have not been under warning in recent months up and down the GDR and points west. Further rainfall next week may keep the water table very high in catchments slowly receding from this week's rainfall.

DATA

Euro 00z - Surface Pressure Pattern and Rainfall Distribution Next 10 days

The pressure pattern is largely unchanged as we track a deep trough into a moist airmass sitting over the eastern inland of the nation. This is leading to a significant increase in rainfall across the eastern states during the coming days, starting with showers and storms throughout the east and parts of eastern SA on Tuesday. A weak trough will likely move east to clip the SWLD of WA bringing a few showers during Wednesday ahead of a stronger system during Thursday. Meanwhile, Wednesday through Thursday is where we see the east coast event peak with significant rainfall and thunderstorm activity across QLD, NSW and VIC. Some of the storms could be severe and flash flooding is a high risk. SA could see some reasonable rainfall as the low slowly moves over the region, meandering about with one or two storms or the Ag Areas, better rainfall for the eastern districts. Over in the west, we will see another system pass through on Friday with areas of rain and a few thunderstorms about, this rainfall the most widespread of the week and likely extending east and south throughout the state. This system will quickly run across to be near the Eyre Peninsula during the weekend bringing gusty winds and showers, then onwards to the southeast by Sunday. Another system is likely to then move through the eastern states bringing a burst of showers and gusty winds for the region. Yet another system is likely to approach WA at the end of the period bringing further rain periods.


Euro 00z - Precipitable Water Anomalies Next 10 days

The PW Anomalies are largely unchanged with a decent supply of moisture running down the GDR this evening, and starting to already be picked up by a trough producing showers and thunderstorms. Some of the storms are putting out a decent amount of rainfall through southern QLD. The moisture will continue to be drawn south into NSW and VIC on Tuesday with showers and thunderstorms breaking out. The moisture may creep into eastern SA and then be wrapped into the low pressure as it rolls into the southeast, backwashing moisture over SA Wednesday and Thursday with increasing showers. A deep pool of moisture sits over the eastern inland during the second half of this week, and it will not be until Saturday that the moisture begins to move out. Another surge of deep moisture comes through the SWLD of WA, this will be the focus of the most widespread rainfall for the region this week. Some of the rainfall could be heavy thanks to the deeper moisture out of the Indian Ocean. Over the tropics the moisture should begin to deepen once again and likely to run southwards next week.

Euro 00z - Rainfall Distribution Next 10 days

Rainfall is largely confined to southern and eastern portions of the nation, the heaviest of it coming through this week over the eastern inland of Australia. Flooding is a concern for areas along the GDR in NSW, particularly the catchments over the central and southern reaches of the range. The flood risk also high over northeast VIC. QLD can expect the best rainfall chances for inland areas since July. The weather does not quite clear the eastern inland through the weekend, with still scattered showers about, but the rainfall intensity will be diminished somewhat. The rainfall will be most widespread over in the west of the nation by the time we hit the end of the week with a good supply of moisture coming into the system as it passes through from the Indian Ocean through to the southeast. Over the north, scattered showers and storms will begin to redevelop as moisture deepens and the upper levels become more unstable.

Closer look

Apologies again about the technical difficulties. I will alert if there are any reasons to go to the forum which is the back up blog if this goes down. More on the climate outlook tomorrow.


151 views0 comments