Jimmy

I haven’t really checked in TS Hanna in a while (maybe as long as 36 hours?) in all the Gustav excitement, but I’ve just looked a Hanna a bit more closely and am amused (confused?) to see that it’s a bit farther south than I was expecting. Apparently it’s been defying the NHC’s forecasting tracks (and the computer forecasting models, since that’s what the NHC bases their forecasts on) and has been traveling west or west-northwest rather than straight northwest. Bad Hanna. This, um, alternate track has prompted a tropical storm watch for the Turks and Caicos Islands and parts of the Bahamas.

It has also apparently very much confused the computer forecasting models, which have resorted to spaghetti-ploty-ness to deal with their confusion:

(Live updating plot of computer forecasting models.)

I look forward to seeing how the NHC deals with that mess in their 5pm advisory package!

Actually, if you look closely you can see a bit of a pattern emerging (it also helps to only look at a few of the models): Hanna will track generally westward until it’s just north of the Turks and Caicos Islands, at which point it will take a turn toward the north-northwest, after which point it will gently curve toward the southeastern US coast.

The official NHC forecast from 11am doesn’t have the north-northwestward turn in there, but they do discuss it in the forecast discussion a little bit. We’ll see what they say at 5pm.

The intensity forecast depends greatly on where the track goes, because that effects things like shear and oceanic heat content, so I’m not going to really even try with the intensity forecast, except to say that Hanna will probably continue to slowly strengthen over the next several days and might reach hurricane status sometime during the next 5 days.

Gotta go now. Keep an eye on the Hanna tag for all my posts on this storm.

-j

Posted in: Tropical Weather by jimmy / Tags: Hanna, Tropical Weather