MODELS AND RAINFALL - TIFFANY CERTAINLY MAKING THINGS TRICKY IN THE RAINFALL FORECASTING DEPARTMENT.

Well as I have alluded to, the modelling will bounce around with the track and movement of Tiffany very hard to pin down. Does she move far enough south through the Top End to be dragged southeast by a wave passing through southern Australia, or does she miss the train so to speak, and stay up north bringing major flooding.


It will have massive implications on rainfall nationwide and so many questions remain about who gets what, not just in the medium term, but now in the short term as well with the models splitting.


Lets take a look at the latest guidance.


SHORT TERM

Clearly the item on the board is Tiffany, expected to cross the southeast of the Top End and then track west into the Central Top End near Katherine before slowing down. Now that is the general idea that has been on the board, some of the other models do take her in other areas which you can see below. Otherwise the southeast and east seeing a sharpening trough combine with moisture to produce severe weather from Thursday through the weekend before drier weather returns. But do we see Tiffany make an impact within the week? That remains to be seen.


UKMET - Rainfall Next 7 Days - MODERATE CHANCE

The model suggests Tiffany will stay up north for the most part before spreading her moisture south and southeast next week but not coming out of the NT until after this period. So this is in line with the higher skill score models tonight. The rest of the nation relatively quiet ahead of that tropical moisture. Just the one storm outbreak to come for the east.

MEDIUM TERM

Refer to the blurbs for more.


ICON - Rainfall Next 8 Days - MODERATE CHANCE

Similar to the UKMet and keeps the majority of Tiffany in tact over the NT before shearing her off to the south and southeast later in the period but not impacting the southeast and east of the nation until after this period. Meanwhile, mostly dry weather for the remainder of the south.

CMC - Rainfall Next 10 Days - MODERATE CHANCE

As explained in the video tonight, whether the tropical feature can hitch a ride with the wave passing through the south next week remains to be seen. If the upper high breaks down, then the system will move southwards.

EURO - Rainfall Next 10 Days - MODERATE CHANCE

Still leading the pack in terms of it's handling of the event thus far, but in the short term, where does it make the turn south and when. Tonight it has suggested that may happen a little quicker, and has also placed the tropical feature further west on the single run, the ensemble data is wetter.

ACCESS - Rainfall Next 10 Days - MODERATE CHANCE

Takes the system further east through the NT and then into QLD and beyond in the medium term with heavy rainfall spreading across the eastern half of the nation. This will see flooding expand across multiple jurisdictions.

KMA - Rainfall Next 12 Days - MODERATE CHANCE

Very similar to ACCESS taking the system east and southeast, unable to be absorbed into the wave passing over SA and then into the southeast states. So it will likely see the heavier impacts remain up north.

GFS - Rainfall Next 16 Days - LOW CHANCE

Every run it is more and more wild and volatile. Takes the system too far west and is too fast with it.

ENSEMBLE DATA

Still the better data sets to look at in terms of accuracy and guidance.


GFS - Rainfall Next 16 Days (median of 35 members) - LOW CHANCE

A little too far west with the tropical impacts at this time, but not implausible. Rainfall to return in the day 7-15 range across the east and central parts of the nation.

CMC - Rainfall Next 15 Days (median of 30 members) - MODERATE CHANCE

Wetter through the Top End than the deterministic data suggesting more adjustments will be made as better data comes in from the upper air network on the tropical item in coming days.

EURO - Rainfall Next 15 Days (median of 51 members) - MODERATE CHANCE

Still the more aggressive on keeping the moisture for the north longer, and then drip feeding it south in the medium term. But numbers are coming up over southeast and southern Australia too.

LONG TERM


CFS - Rainfall Next 6 Weeks - MODERATE CHANCE

As outlined today, the wet weather peaking in the coming 6-12 weeks across the nation.

More coming up from 830am EDT.