It has been well forecast here for the past week for the tropics to turn very active north of the nation, with a deepening monsoonal flow and the passage of the MJO whipping the rainfall and windy weather up.
The bulk of the heavier rainfall is likely to stay offshore through mid week, but the models struggle to place the heavier weather from later this week. Some models bring a tropical low over the Top End, other models form that over the Timor Sea and another near Cape York.
One way or the other we will have to watch closely as the weather can change very quickly at this time of year with the risk of tropical rainfall increasing within 24hrs for one location very high.
The severe weather potential remains moderate at this time.
For the south, the air is dry and mostly stable but the weather will likely turn more humid as we go along this period, and next week, we could see some showers and thunderstorms return to the forecast packages after a dry and hot week.
Lets take a look
Rainfall Next 10 Days
Rainfall is likely to increase over the coming days about the north coast as the modelling supports the troughing building offshore. There is a chance of a low forming in the trough during the week and into the weekend which may enhance rainfall over northern areas. The weather over the Top End in advance of that will see showers and thunderstorms increasing in the coming days with gusty winds and locally heavy rainfall. Showers may turn to areas of rain with thunderstorms and locally heavy falls by the end of the week into the weekend. Locations to be determined through this week.
The rainfall further south is likely to be lean south of Renner Springs, though the coverage will eventually reach the SA border by the end of the period, with isolated showers and thunderstorms returning to the forecast packages.
Thunderstorm Forecast Tuesday
Thunderstorms will return to the same areas again on Tuesday with some of the storms tending gusty and heavy about the north coast. There may be coastal thunderstorms during the overnight and morning hours about the northwest Daly coast as well. Inland areas will see gusty winds with thunderstorms.
A broader look through the NT
Tropical Depression Risk - This Week
With the monsoonal flow developing over the open water during this week you will notice larger clusters of thunderstorm activity. These clusters may become more organised and low pressure systems may develop. Given the elevated SSTs through the region (not as elevated as per January but it is sufficient) depression formation is quite likely from later this week and through the weekend. Refer to the chart to that shows you where the models are placing the tropical depressions and where they ago. The confidence in identifying the system that is the dominant tropical low is very poor.
Tropical Cyclone Risk - This Week
With the monsoonal trough sitting over the open water and the MJO passing through the north of the nation from the weekend and into next week, any tropical low that forms in the waters offshore the coast, carry a moderate chance of developing into a cyclone. The most likely outcome based of analogue data is that a system will form north of the NT and then head west through the Arafura, Timor and then Indian Ocean. That will then deepen offshore northwest WA and then turn towards the Pilbara and then inland through WA. That would spread heavy rainfall over the northern tropics but then pull the heavy rainfall shield away from the NT and over WA and another pulse of monsoonal weather would develop over Cape York.
DATA - Refer to video for more information and the daily breakdown
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks
A dynamic weather situation is unfolding across the nation over the coming 10 days and many areas will see 1-2 months worth of rainfall through northern and eastern VIC, much of inland NSW, through inland QLD and much of the tropics. This is in line with the wet signals off the global models and the climate drivers and should come as no surprise here as we have been talking about the wet end to February and start of March for some time. The weather is supportive of severe weather developing as well as riverine flooding developing as well. More to come on that through the days ahead and more analysis in the video.
00Z GFS - Precipitable Water Anomalies - Next 2 Weeks
The very deep moisture profile over much of Australia looks more likely to be with us for the next 10-15 days, especially over northern and eastern Australia where low pressure is in place and likely to remain, leading to the moisture being lifted into above average rainfall and thunderstorms. This reflects the above average moisture content in line with a waning La Nina phase.
00Z GFS - Rainfall Accumulation - Next 10 Days
Refer to video for further analysis
00Z CMC - Rainfall Accumulation - Next 10 Days
Refer to video for further analysis
00Z GFS - Rainfall Accumulation - Next 16 Days
Refer to video for further analysis and the fly around with your state and further details.
A closer look in - the numbers are starting to reflect a flood risk over coastal areas in the coming week or two.
More coming up in the models and rainfall analysis for the coming short, medium and longer term data and tomorrow more details from 8am EDT.