NT - MONSOONAL WEATHER STRENGHTENING THIS WEEK. INCREASING FALLS FOR THE NORTH. DRY SOUTH.

The weather is split into two camps which is not unusual for this time of year in the NT. Showers and thunderstorms extending south to about Tennant Creek this week with a trough and anywhere north of there recording humid weather with unsettled conditions. The weather over northern parts of the Top End could turn quite wet with some modelling suggesting the MJO moving through by the end of this week.


A tropical low developing in offshore waters in the Arafura Sea is quite likely which is expected to move southwest through the coming weekend and then into next week.


The second trough moving south to Tennant Creek will produce showers and thunderstorms, some of those could be severe with damaging winds and heavy rainfall leading to flash flooding.


South of the trough over the Simpson District will remain dry including the Alice Springs region with temperatures increasing to the low 40s under an upper high.


Into the medium term, all eyes on the developing monsoon, and the question remains unanswered for now, how far south does the moisture spread and how much influence will the tropical weather have on the conditions over interior parts of the nation moving into March.

FORECAST

Rainfall Next 10 Days

Rainfall increasing over northern parts of the NT with thunderstorms activity starting to increase over the coming week, bands of storms moving east to west of the Top End with locally heavy falls and strong wind gusts will become more frequent. By the end of the week, showery periods, with heavy falls for coastal areas may turn to areas of rain where a tropical low may form north of Arnhem Land or the Daly. That is an area of concern as these systems can develop quite quickly. The wet signal continues right through the outlook period.

The remainder of the NT looks drier the further south you go. Some of the storms as you get to Tennant Creek may be severe with heavy rainfall leading to flash flooding from mid to late week. Drier weather is expected towards the SA border for now, but watching the influence of tropical moisture from the north.

Thunderstorm Forecast Monday

Thunderstorms are forecast to become more active over the Top End during Monday. There may be clearing thunderstorms over the northwest Daly from overnight activity. New activity may form over inland areas of the Top End by lunch and organise into squalls moving westbound late afternoon. Damaging winds are possible with thunderstorms over the Top End. Thunderstorms may also develop about the northeast and north coast during the morning with maritime convection.

Damaging Winds Forecast Monday

The risk of damaging winds is a moderate risk with thunderstorms moving westbound in bands across the Top End. Damaging straight line winds of up to 100kmh are possible.

Flash Flood Risk Monday

A moderate to high risk of flash flooding with heavy thunderstorms over the Top End with bands of storms training over the same region.

DATA - Refer to video for further analysis and guidance relating to the forecast charts above and the movement on the data sets.


00Z GFS- Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

Not much change from this morning for the short term, but from later in the outlook period, the spread, depth and scale of the monsoonal weather over northern Australia will have consequences for the nation's weather. There is likely to be tropical low pressure form or cyclone activity form over northern parts of the nation. Classically, as we move into early March, the traditional format for rainfall spreading across the nation is from northwest to southeast from WA, through central interior and SA and then into NSW and VIC. This is a decent chance. Across the east of the nation, onshore winds for the coming week will see frequent showers for the NSW and QLD coast, locally heavy with cooler temperatures. The onshore flow will feed the trough over the inland producing showers and storms on a daily basis for much of QLD, NSW and into the ACT and northern VIC. Overall the nation will turn wetter as we go through the outlook period. Once we get to the end of the first week of March, we could have a neutral SAM, reducing rainfall risks along the east coast and bringing back the frontal waves for southern Australia, helping to bring in more moisture from the north and northwest so that is something to watch. Not an overwhelming signal but is there.

00Z GFS - Precipitable Water Anomalies - Next 2 Weeks

Moisture spread across the nation remains unchanged, it has been building in recent days and is likely to increase further then drift south through to VIC by the middle to latter part of the week. The moisture over northern Australia rising sharply as the trough north of the nation deepens and a monsoonal westerly flow moves closer to the nation. If we have a low pressure system developing north of the nation as the GFS says this week (has picked the tropics reasonably well this week), then we could see widespread rainfall develop earlier than what other models are suggesting. Refer to the rainfall and models post this evening.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for further guidance

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to video for further guidance

00Z GFS - Rainfall Accumulation - 2 Weeks

Refer to video for further guidance and a state based fly around.

A closer look in - the wet weather is expected to increase throughout this week with the potential for tropical lows forming near the north coast but not all models agree. So be aware that this forecast is low confidence.

More weather information coming up later this evening with the models and rainfall wrap and as mentioned in the email agenda today, plenty on the board to cover off this week.





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