She is ruling the roost when it comes to weather across the northern half of the NT, with a major flood likely to develop in response to her arrival on the east coast but also due to her very slow movement as she moves over the inland river systems. Once again, I cannot stress the importance of being prepared for major flooding, even if it does not occur, this is a timely reminder about being weather aware during the wet season.

Heavy rainfall is expected to develop for the northern parts of the Top End, with Darwin and surrounds expecting to see heavy rain periods, local thunderstorms and squalls. This weather is expected to remain in place well into next week. Local flooding is expected in the river systems and across causeways and roads through the Top End throughout the next week as well.

For southern areas, the weather is expected to be hot to very hot with increasing humidity. Showers and thunderstorms are likely to return from the weekend with locally heavy falls for the Barkly and this extending into the Simpson and further south into the medium term.

Lets take a look


Rainfall Next 10 Days

Rainfall remains very much the feature across the Top End with areas of severe flooding possible as the remains of TC Tiffany slowly moves through the Katherine region. Significant rainfall is expected to redevelop for the northern coast as well as the monsoonal northwest flow establishes into next week. Some locations could get 500-800mm through this period. Rainfall will spread further south through the NT with showers and storms increasing as the moisture from the cyclone also moves southwards.

Tropical Cyclone Tiffany

Tropical Cyclone Tiffany will strengthen into a category 2 overnight, possibly a 3 before slamming into the eastern Top End. The system once interacting with land will lose the destructive wind core and the system will commence raining itself out with widespread flooding expected to develop, that being the major feature of the event for the north of the nation.

Flood Risk Northern Territory

Flooding is the main concern over the coming days with heavy falls exceeding 500mm possible in the dark green zones. Falls up to 300-500mm is expected over the remainder of the area shaded through this period.

Thunderstorm Forecast Wednesday

Severe thunderstorms are expected to develop with outer bands from the tropical system passing through the eastern Top End, likely to reach Katherine through the afternoon and Darwin through the late afternoon and evening. Damaging winds are the main risk with storms, these could exceed 100km/h.

Flash Flood Risk Wednesday

Thunderstorms may produce flash flooding through the northwest Top End through the afternoon and evening as a spiral band works it's way in from the southeast with heavy rainfall rates. Flash flooding is a major risk near the cyclone landfalling location. There could be rainfall rates of 70-100mm/hr.

Damaging Winds Risk Wednesday

Damaging winds of 100km/h possible with a band of thunderstorms working north through the NT. The storms will organise into a squall line and bring the risk through Darwin and surrounds during the afternoon and clear north through the evening.

Tornado Risk Wednesday

One or two tornadoes are possible over the Gulf region during the day with the cyclone making it's move towards the coast.

DATA - More information can be found in the video where I use CMC this evening.

00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

GFS is on drugs tonight. There is no other way of putting it. So I want you to use other agencies until it settles down. It is an outlier. The moisture from the tropics likely stays in place until next week before we see any evidence across the board of that moisture heading south and east across the country. Otherwise we have got a major flood event for the NT over the next week. Severe storm outbreak later this week into the weekend for the southeast and east and dry boring predictable weather for SA and WA. That is probably the easy part of the forecast right now. Finally, note the tropical systems into the medium term, that expresses to me that the tropics remain active for the remainder of the month, not that cyclones are hitting WA in the medium term.

00Z GFS - Precipitable Water Values - Next 16 Days

Where the tropical system goes, so to does the rainfall opportunities up north. The moisture from this system will be distributed across the country but exactly where remains to be seen. But here is an example of what happens when that moisture does get drawn across the country. It is unlikely to occur but a good example non the less.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to video for more information

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to video for more information

A closer look in with CMC over the next 10 days

A broader look at the region

00Z GFS - Rainfall Accumulation - Next 16 Days

Refer to video for more information

More weather coming up this evening with a look at all things models and rainfall as we eye off the tropics and see how that large flood event will impact areas further south and east.

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