MORNING WEATHER WRAP - STORMS RETURN TO THE EAST - STRONG FRONT APPROACHES WEST.

Fine weather in between for much of this week as a blocking pattern in the Tasman with an upper low offshore QLD and strong upper high over NZ. That will force systems out of the west to the south as they approach the southeast. Dry air on the western flank of a weak low pressure system offshore VIC will send in dry air from the south this weekend bringing about a week of relatively dry weather now for a good chunk of the southeast inland.


The more active parts of the nation will be the west with a strong cold front tomorrow morning with a low pressure system attached, that will be helping to drag along some gusty winds and areas of rain and thunderstorms tomorrow with heavy falls.


The east of QLD and parts of eastern NSW will see showers and thunderstorms at times throughout this week, with onshore winds combining with a series of troughs. Some of the storms could be severe with heavy rainfall, damaging winds and large hail about.


Lets take a look

Rainfall next 10 days

The weather contracts on and east of the Great Dividing Range in QLD and NSW with a coastal trough and upper low wafting about this week, with middle level troughs running over the region from the west bringing the coverage of storms up from time to time through the outlook. The west coast of WA will see a fair smack of rainfall and gusty winds from tomorrow that eases through the remainder of this week, trending drier by Friday. For the tropics, the coverage of thunderstorms will likely increase this week with a trough about the base of the Top End. The southeast inland, haven't said this much this year, mostly DRY with an upper high looking to take up residence with dry air underneath.

Thunderstorm Forecast Monday

Thunderstorms are forecast to develop over parts of eastern QLD and northeast NSW with a trough developing off the coast and another mid level trough moving through from the west. Onshore winds feeding the trough will support the development of showers and thunderstorms this afternoon, some of the storms turning severe over inland areas before moving towards the coast. Those areas west of the GDR in QLD and NSW should stay dry. Coastal showers over the remainder of the NSW coast should stay below thunderstorm thresholds though lightning may be visible offshore.

Damaging Winds Risk Monday

Winds could reach damaging thresholds with the thunderstorm activity today. The winds aloft are fairly robust and some of that could be mixed to the surface with the strongest storms today. Otherwise low chance of damaging wind gusts over the Top End, over the southeast inland and along the west coast of WA later tonight with the approach of the front.

Flash Flood Risk Monday

Moisture is sufficient for heavy rainfall with thunderstorms over eastern QLD and northeast NSW that any training of thunderstorms will result in flash flooding. Low chance of flash flooding over the inland of the Top End with slow moving storms.

Large Hail Risk Monday

Large hail is a risk with thunderstorms today. The upper levels are cold and there is a drier slot through the mid levels to support hail development, but out of the three risk modes, this would be the lowest of the modes. But expect the unexpected in storm season.

DATA


Euro 12Z - Surface Pressure Pattern and Rainfall Distribution - Next 10 days

The pressure pattern is slowly but surely moving away from the westerly wind regime, with the winter belt shifting further south after being quite active this Spring so far. The pattern is expected to turn more meridional this week, meaning troughing and weather systems shifting from north to south and you can see that impact in a drying out of the southeast where an upper ridge is able to develop. On the periphery of that ridge you can see troughs producing showers and thunderstorms, one in the east, one over the west and over the north throughout the period. In the southeast low pressure systems in the Tasman moving north injecting dry air into the eastern inland west of the divide through NSW and QLD keeping things quiet, in combination with that upper ridge in place.. Under that ridge the southeast will warm up a bit this week too, even following the front passing over later this week, the winds are not cold as they have been in previous weeks. Out west, perhaps the last strong cold front of the season is coming through tomorrow before being shunted south of SA due to the blocking pattern in the east. Over the north the tropical easterly winds are likely to move further south in the coming 10 days and this is where you can see the moisture now running into the west coast trough into the medium term. All signals the weather is starting to shift further.

Euro 12Z - Precipitable Water Anomalies - Next 10 days

You can see the role of the low pressure in the Tasman Sea not only acting to block the passage of the frontal weather and troughs out of the west with deeper moisture and rainfall chances, but note the injection of dry air over the east and southeast inland through the period, as the system oscillates through the region. Meanwhile, deep moisture over WA will bring extensive cloud and rain areas for Tuesday which may run across the south of the nation before moving offshore the coast from Wednesday. The north, above average humidity values as expected with that playing out with more widespread falls further south throughout the north than usual, the early onset rainfall unfolds. And the east will see showers and thunderstorms with troughs from time to time, the moisture over QLD remains near seasonal for most of the period so seasonal rainfall expectations can be forecast for now. Much of the inland looks stable, dry and warm.

Euro 12Z - Rainfall Accumulation - Next 10 days

You pick out the position of the upper ridge, which has been sitting over WA for a good 6 weeks, it is now likely to be placed over the central and eastern interior with a dry airmass, bringing low rainfall chances for much of the period. The rainfall strictly coastal over the east and about the adjacent ranges. The southeast coastal areas may benefit from two troughs bringing showers and storms Tuesday and again on Saturday. That second trough bringing more widespread storms to QLD from later this week into the weekend. The main event on the board is the west coast event from tomorrow, with heavy rainfall and strong winds and many areas out there likely to record over 1 months worth of rainfall. The northern tropics, hit and miss showers and thunderstorms to continue but most areas should get a good go of it this week, with 30-40mm likely for many areas. Much of SA and western NSW dry for now. But watch the moisture pooling to the north and west for the last 2 days of the month.

GFS 12z - Rainfall Accumulation - Next 16 days

Refer to the video for more.

CFS 12z - Rainfall Accumulation - Next 6 Weeks

Refer to the video for more.