NSW - RAIN OVER THE NORTH EASING TUESDAY - SHOWERS AND STORMS FOR THE STATE FROM MID WEEK.

An active phase continues as we track multiple troughs through the nation from west to east, these picking up the moisture that is sitting over the eastern inland.


We have one more upper trough passing through this afternoon over the far northern regions of the state, this trough is likely to deepen into a low pressure system from overnight into Tuesday with possibly some heavy falls about the NE coast bordering SEQ.


The next trough is expected to arrive as quick as the first system clears, another burst of showers and thunderstorms are forecast to develop. These storms could pack a punch with a deep low pressure system winding up south of Adelaide producing gales and showers, but in the warm sector, strong to severe storms are possible before the colder weather arrives.


The storm activity lingers over the northeast into the weekend with widespread showers for southern districts clearing over the weekend.


Next week, we go from below average temperatures to above average temperatures with some areas experiencing their coldest weather in about 6 weeks this weekend to the warmest weather so far this Spring in a matter of days


Lets take a look at the latest guide.

Rainfall next 10 days

Rainfall likely to be patchy over the northern areas tonight though may become more widespread from the New England and Northern Tablelands through to the Northern Rivers with the passage of a deepening trough. Some heavy falls are possible. Then rain clears the coastal areas from later tomorrow. The next trough as mentioned passes through southern areas from mid week, this bringing a band of showers and thunderstorms, will track the coverage of severe weather potential in more detail tomorrow but there may be some moderate to heavy falls with any thunderstorm activity. Then cold and showery for the southern half with a few storms over the northeast clearing east this weekend. The next trough is anticipated to move east from WA into SA early next week but ahead of that, hot weather, then storms developing. Regional charts issued Tuesday ahead of the storm outbreak Wednesday, need to see another few data sets first.

Thunderstorm Forecast Tuesday

Scattered thunderstorms are possible, mainly north of the QLD border with a low pressure trough and circulation passing through the region. If the low develops further south, then thunderstorm coverage may be more potent through NSW, so will have to watch radar trends. The main risk is heavy rainfall given the soupy airmass aloft, so any thunderstorm that forms will be efficient rainfall producers.

Flash Flood Risk Tuesday

A low to moderate risk of flash flooding along the east coast with a developing low offshore and with thunderstorm activity mainly north of Narrabri towards Mungindi and points east. We were spared the flash flood risk today thanks to thick cloud cover, however I do want to point out that some of the severe risks with these dynamic weather systems may be mitigated by cloud cover this severe weather season.

Thunderstorm Forecast Wednesday

Thunderstorms are expected to form along the trough passing in from SA into VIC and NSW during Wednesday. Thunderstorm activity may be strong with a supportive wind fields aloft and decent instability, thunderstorms will be capable of producing damaging winds and large hail. Heavy rainfall the lesser threat at this stage. The severe risks are marginal this far out but pay attention to the forecasts.

DATA


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

A low pressure trough and two upper lows are traversing the east making rainfall forecasting very tricky at the moment through the eastern inland with strong storms now flaring in areas where there was no risk. This is pattern is expected to continue overnight and into Tuesday. A strong cold front passed through the SWLD of WA today with significant cold air surging north and a fairly robust area of showers throughout the region. That front will race through to be near the EP of SA tomorrow afternoon and then the trough will be over the southeast of the nation Wednesday. It will run into a deeper moisture profile left over by the lead system through NSW and QLD currently and see showers and storms increase once again. Severe thunderstorms are possible. The west will dry out for the remainder of the week into the weekend with above average temperatures while the east will be cold and showery over southeast SA and VIC thanks to a low near Tasmania. That low may cause severe weather over Tasmania as well. Storms on the trough over NSW and QLD on Friday will lift off the east coast during the weekend. Over the tropics the weather is seasonal with scattered to numerous showers and thunderstorms with the day time heating process. Next week keeping an eye on a strong trough/front approaching the west of the nation which may bring a burst of heavy rainfall and strong winds and cooler weather, while the east turns quite warm to hot and settled under high pressure. The east coast however, thanks to that high, may sit under a moist unstable showery easterly airstream. There is lots on the board for the next 7-10 days.

Euro 00z - Precipitable Water Anomalies - Next 10 Days

Moisture profile is largely unchanged from this morning, the issue is pinning down systems in the 5-10 range. This time yesterday the Euro had a deep low sitting over southeast Australia, tonight it is hot and dry with a northwest flow with moisture to the north. Safe to say we take it one system at a time over the nation. For now the next system on the board to watch is the rain and thunderstorm event over the southern and southeast of the nation mid to late week with a high chance of heavy rainfall for VIC and TAS and moderate falls into NSW. The moisture profile not especially excessive but the unstable air will lift the moisture to full potential. The northern and northeast of the nation remaining humid and unsettled with the dry air from the strong system in the southeast failing to get up into the tropics now. The seasonal shift has evolved now beyond this occurring. Finally the last system to watch is the large scale moisture in feed from the Indian Ocean through WA into a strong front which could bring above average rainfall out west.

Euro 00z - Rainfall Accumulation - Next 10 Days

Rainfall confidence remains low as per the commentary above and will likely shift around in the medium term. Rainfall tonight over QLD and northern NSW could be heavy in spots. With severe storms north of Boulia, there have been reports of 20-35mm with those seeing 2 months worth of rain in a sitting. We are moving into that time of year now. Some of the rainfall for SA, VIC and southern NSW could be moderate to heavy with the next feature on the board mid to late week. The falls with the second system more isolated for northern NSW and into southern QLD as the trough passes through. The north sees scattered falls with the afternoon downpours about. The third system to watch is the one out west which could bring above average rainfall to WA.

A closer look in

GFS 00z - Rainfall Accumulation - Next 10 Days

Refer to the video for more information.

I will have more on the rainfall chances and models tonight after 9pm EDT and a look at the climate drivers and a harvest update tomorrow.


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