Wednesday, September 05, 2012

Hurricanes Leslie and Michael, and the Gulf of Mexico Blobette: September 5, Udpate A

Not much time for dilly-dallying tonight, but at least I’m in one of my normal time zones! J

Hurricane Leslie
As expected, Leslie was upgraded to a weak cat 1 with winds of 75mph today (central pressure 985mb), however she is a bit messy for a Hurricane. That dry air is still creeping in and is now very close to the center. There is still also some lurking wind shear, and as expected, the water underneath is cooler now because she’s been there for so long. If it wasn’t for the strong circulation in all levels of the troposphere, I would downgrade her to a Tropical Storm for now because the convection is quite weak as you can see in the infrared satellite image:

Because of her messy appearance it is a little difficult to figure out her exact center but the NHC location looks more-or-less close enough at 26.2N,  62.5W. She is moving N at 2mph – and even that is a little dodgy as a direction and speed estimate. It looks like she’s just going round in little circles. Maybe she fell asleep counting fish…

The forecast has her upgrading to a Cat 2 storm on Friday, when she will finally begin moving. I am not sure this will happen. They may be factoring in her anticipated forward motion as well, but if she is that strong she’ll have a well-developed and consistent eye by then, which she certainly doesn’t have at the moment. Regardless of intensity, her wind fields are quite extensive and I believe the surfers are enjoying this along the east coast of Florida!

It looks like she will pass the Bermuda area on Saturday. It’s tricky to tell whether she will be to the east or west or over the island at the moment because there isn’t enough guidance in the pressure data. I know you are all getting ready. Two people have mentioned to me in the last two days that Bermuda has the best rum in the world. Also, Steve W. from Florida kindly requests that you (the Bermudan people) secure the Gosling Rum factory, and if you are evacuating, please bring all the rum with you.  

Hurricane Michael
He was just upgraded to a hurricane with winds of 75mph, central pressure 990mb. He is at 29.3N, 42.2W, moving NE at 7mph. Michael is a good looking little storm, with a very clear eye. The persistence of the eye suggests to me that his winds are probably closer to 85mph. It isn’t a big deal though because just like Earth in the second edition of The Hitchhikers Guide to the Galaxy, he’s mostly harmless. J  The convection is not as strong as it could be, and there is some wind shear so clouds are streaming off to the northeast. These suggest that he’s not developed enough to be a cat 2. He will continue to experience wind shear which may help to inhibit him. I agree with the NHC – I don’t think he’ll get as strong as a cat 2 storm.  

Gulf of Mexico Blobette
Our potential little daughter of Isaac has moved into the Gulf now, with all its lovely dry air and wind shear (although the waters are warm enough for some convection). She doesn’t have very strong circulation in the troposphere at the moment – in the lower troposphere the vorticity is connected all the way to the mid-west, and in the middle of the troposphere the vorticity stretches to Mexico, which suggests that she’s more of a front-type thingy (technical term ;-)). Although the computer models take her east, skirting the northern Gulf towards Florida, I think she’ll continue southwestward for longer than they expect. She’s not organized enough for me to see a center, but I guess if there is one it is around 28.5N, 89W, just off the Mississippi delta.

The NHC give her a 50% chance of developing in the next couple of days. They’ll send a plane in tomorrow afternoon if they think they need more info. Until that vorticity (circulation) improves, she won’t be a Tropical anything.

That’s it for today folks! Tomorrow is another mad-cap sort of day (it’s a Thursday… what else could I expect? ;-)). I’ll try and get something about about Leslie and the blobette if I can though.


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DISCLAIMER: These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

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