NSW - RAIN AND THUNDERSTORMS TONIGHT AND MONDAY MAINLY NORTH - SHOWERS AND STORMS MID WEEK.

Active period is underway as forecast with a decent amount of instability kicking off showers and thunderstorms this afternoon and this evening across the eastern seaboard with a southerly change and rain and thunderstorms along a deep trough over the north.


Areas of rain and a few thunderstorms still expected to pass through northern areas during Monday with drier air sweeping through the southern areas during the Monday morning clearing skies.


A low pressure system is expected to form along the trough over northern NSW during Monday night into Tuesday with some heavy rainfall possible as that process takes place. The weather drying out over the north.


Another low pressure system and trough approaches the state from mid week with an active period of thunderstorms possible over the course of mid to late week and a cooler shift into the weekend for southern areas.


Lets take a look

Rainfall Next 10 Days

Rainfall is extensive in nature tonight over the state with a trough moving into western areas and a southerly change moving north along the coast. The two will likely merge during Monday afternoon and evening increasing rainfall for the northern and northeast of the state. Drying weather expected over the southern districts tomorrow. Another trough enters the west and south of the state during Wednesday and through to the end of the week, more showers and thunderstorms will be active throughout the state, some of those could pack a punch. Another trough approaches the state during the medium term with further rainfall. Flood Watches have been issued for northern areas.

Thunderstorm Forecast Monday

Thunderstorms are active tonight and through Monday, mainly for central and northern areas of the state. Some of those storms tonight could turn briefly severe about the Central and Hunter coast. More thunderstorms within a rain band could produce flash flooding but the surface based instability is not quite as high as today.

Flash Flood Risk Monday

Flash flooding is expected to feature with some storms tonight over coastal areas and through the northeast with a trough deepening into a low pressure system. Thunderstorms on the northern and eastern flank of where that low forms in response to the southerly change moving north will be the focus of heavy rainfall.

Flood Watch Areas - Next 6 Weeks

Flood watches are officially in place for the northern inland and may develop over the northeast. It is going to be a very tricky period for people living in the southeast inland where catchments are saturated.

DATA


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

An active surface pressure pattern as outlined in the video is also reflected in the Euro this evening with now three events on the board for the east and a strong low for southwest WA emanating from the tropical Indian Ocean. So there is plenty to watch. The ongoing rain and storms over the eastern inland of the nation will continue to drift further east in the coming days with moderate to heavy falls possible. Some of those falls could see up to 1-2 months worth of rainfall for some locations. Then we track another strong system into WA tomorrow which will bring showery cold weather, well below average temperatures. This system helping to knock out the eastern low and trough and quickly bring rain and strong winds to SA and then into the southeast states, and well below average temperatures. This system will forma deep low over SA and then into the southeast later this week and there could be severe thunderstorms in the warm sector over the eastern states ahead of the low and then showery cold weather with local hail and thunder with snowfalls for Alpine areas. Graziers beware. Out west the weather warms up with above average temperatures, that will help form a heat trough which then moves east over the eastern states early in the following week with more rain and storms and possibly another low. A strong low pressure then approaches the west coast of WA with anomalous weather conditions possible, with heavy rain and strong winds. That is something to watch! Over the north, this period will see the usual showers and thunderstorms for much of the period mainly afternoon and evening, this feeding troughs with moisture further south and east lifting rainfall chances.

Euro 00z - Precipitable Water Anomalies - Next 10 Days

You can see the blue shadings across the north and east bringing widespread rainfall chances in the short term and then again in the medium term, watching the Indian Ocean closely as that may have a huge impact on rainfall for the back half of the month.

Euro 00z - Rainfall Accumulation - Next 10 Days

Rainfall accumulation is of moderate confidence in the short term but with the system approaching mid week for southern and southeast areas and then with the system floating off WA later in the period, these carry low confidence straps for now. It is an active period of weather but it is not uncommon to have a lot going on during Spring time. So keep the forecasts close.

A closer look in

GFS 00Z - Rainfall Accumulation - Next 2 Weeks

I will have a wrap on the models and all the rainfall data coming up tonight, there is a lot of weather in the distance and I cannot stress enough the risk this poses for people over the south but more likely to east of the nation.

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