Tropical Cyclone Jasper

[Somerset Squall]

Invest 98P has become rapidly better organised over the last few hours, with deep convection surrounding a very well defined LLC. Therefore, Tropical Cyclone Jasper is born, an intensity is currently at 40kts.

Jasper is currently located in the central Coral Sea. A trough entering the Coral Sea will enforce a continued southeastwards motion. Intensity is likely to be capped by moderate to high shear, until Jasper enters colder waters which should induce extratropical transition or dissipation in a few days time. On the southeastward heading, Jasper is unlikely to affect land.

[Things]

Wow, Last night Jasper was very unorganised, and I wake up this morning, and it has an eye already :o

[kold weather]

Thats not an eye things just a dot, though I grant you I needed a second take!

Still convection does seem to be wrapping somewhat towards the center of the Jasper. I suspect that shear has eased off somewhat in the last 6-9hrs and this has allow the system to start and wrap up, though for now banding features are lacking somewhat. For now the shear is holding low enough for deep convection to take hold, though whether or not it continues has to be seen, thats the reason why the forecasts are keeping this system at pretty much same strength, but we shall see what happens with the shear over the next 24-48hrs. Jasper has a weak steering currents to the south of it so it may well slow down somewhat, though current movement is towards the SE.

Edited March 23, 2009 by kold weather

[Cookie]

thanks for the updates this system looks good already

[kold weather]

The one thing I will say is if the shear can stay around wher eit is then steady strengthening does seem quite possible given the high heat content we have present in the region its moving, its still looking pretty decent and wrapping around quite nicely in the southern semicircle, thats where the strongest winds will be, as is normally the case in S.hemispheric storms. IF the shear can remian low then we could see some steady strengthening under decent heat content and on top of that inflow looks very good into the eastern quads.

With Jasper heading towards rather slack and uncertain steering currents the forecasts will likely be rather poor for a while yet.

[Cookie]

[kold weather]

Big convective burst has gone up overnight but I think its getting somewhat sheared again, but often in these storms when you get shear convective blow-ups in storms below say 50-55kts you can actually see some strengthening as big convective bursts help to mix down the stronger winds.

Until the shear can ease off for a longer period time Jasper won't manage to keep any sort of textbook look, but saying all this I've seen cat-2's in the Atlantic that have similar presentations to Jasper so that certainly doesn't rule out some strengthening. ECM does suggest Jasper will find a lower region of shear and strengthen quite a bit though exactly when that happens is very much uncertain, IF it does find that lower shear region was it heads back westwards very slowly, with heat content the way it is in the region, no reason why it won't strengthen quite a lot.

[Somerset Squall]

As KW rightly predicted, track forecasts are all over the place. Eventual weatwards drift was predicted, but now JTWC are forecasting an eastwards turn as a subtropical ridge builds to the northeast and becomes the dominant steering influence. However, there is a ridge southwest of Jasper aswell which may create a more competitive steering environment so we can't really be sure just where Jasper will end up.

Jasper is now a 45kt storm. However, as KW says, Jasper is a sheared system which now looks rather disorganised in satellite imagery. Sea temps are very warm which will probably keep fuelling new convection but don't expect any major intensification unless shear eases. JTWC forecasts Jasper to reach 65kts in 24hrs, but this is highly dependant on forecasts for lower shear, which is highly uncertain. It's very much a game of wait and see with Jasper I think!

Edited March 24, 2009 by Somerset Squall

[Cookie]

Jasper if proving an interesting watch

Storm Alert issued at 24 Mar, 2009 12:00 GMT

Tropical Storm JASPER is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

New Caledonia

probability for TS is 55% in about 24 hours

Yellow Alert City(s) and Town(s)

Koumac (20.5 S, 164.3 E)

probability for TS is 55% in about 24 hours

Kone (21.0 S, 164.8 E)

probability for TS is 55% in about 36 hours

Bourail (21.6 S, 165.5 E)

probability for CAT 1 or above is 10% in about 36 hours

probability for TS is 55% in about 36 hours

Noum'ea (22.2 S, 166.5 E)

probability for CAT 1 or above is 10% in about 36 hours

probability for TS is 50% in about 36 hours

Green Alert City(s) and Town(s)

Tadine (21.5 S, 167.9 E)

probability for TS is 35% in about 48 hours

Note that

Yellow Alert (Elevated) is CAT 1 or above to between 10% and 30% probability, or TS to above 50% probability.

Green Alert (Low) is TS to between 31% and 50% probability.

CAT 1 means Tropical Cyclone strength winds of at least 74 mph, 119 km/h or 64 knots 1-min sustained.

TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.

A few hours old image but ceritanly an interesting one

[J07]

I noticed this morning high cloud streaming towards us, it was a jet streak and probably the subtropical jet. It was on a NW -> SE track away from Jasper, and it can't be healthy for that TC to be so close to that sort of feature....

Let's not forget though that NC is not having a good time with this cyclone dallying around.

[Somerset Squall]

Shear has completely destroyed Jasper. There is nothing left of the storm, convection has been stripped away and the circulation has been torn apart. Regeneration is not expected due to continued destructive levels of shear.

[Cookie]

wow, the power of shear, totally ripped this system to shreds!

[Mondy]

looks beefy again

[Somerset Squall]

That satellite run is two days old Mondy . This is the most up to date one- no Jasper.

[Cookie]

looks beefy again

beefy what a word