Wednesday, September 18, 2013

Tropical Storm Humberto and the Yucatan Blob: September 18, Update A

It’s movie night and on the menu is the original The Odd Couple… they are just like our storms! :-) Tropical Storm Humberto is Felix – organized but mostly black and white. The Yucatan Blob is Oscar – rather messy and a bit colourful (with a ‘u’ ;-)).

Tropical Storm Humberto (or Felix)
There is still some circulation in this storm, but mostly in the lower half of the troposphere, with the circulation in the upper troposphere from a low pressure trough. This mix-n-match structure means this is really a subtropical storm, which is what the NHC think too. So we agree thus far. But he really has next to no convection! The latest infrared satellite image:

Mostly black and white, with a nice blue tie. He really shouldn’t be a tropical storm. There’s no thunder or lightning! “What’s the matter Felix? I can tell something is wrong from your conversation.”

Yucatan Blob (or Oscar)
Meanwhile in the southern Gulf, the very messy Oscar-esque Yucatan blob is now over the Bay of Campeche, smoking his cigar, dropping ash all over the floor. The convection in this storm has diminished this evening, but earlier today it was still mostly coming in from the Caribbean side of the Yucatan peninsula. It’s pretty tricky to find the convection that really identifies this storm because at the moment it doesn’t look like anything much – in fact, the strongest convection in the region is over land:

It is also a bit tricky to see where the center of circulation is, partly because there is wind shear. Near the surface the circulation is over the water, but it looks like in the middle troposphere the circulation is still over land (ok, I had to squint, have a glass of wine and stand on my head to even see any middle-tropospheric circulation ;-)). If I were to guess, I’d say the lower circulation is around 22N, 92W, and the mid-troposphere circulation may be around 19N, 91W (maybe).
Poor Mexico. They *really* don’t need any more rain. I read that between Ingrid and Manuel, about 2/3 of the country had been impacted. Sigh.

As for ‘track’, I know the ‘spaghetti’ models are all over the Gulf. From the pressure fields it looks like it will remain in the southern Gulf, and may even head a little south (towards land) tomorrow.
I’ll keep an eye on this Odd Couple and be back tomorrow. Here’s a psychological question to ponder: are you a Felix or an Oscar? I'm sure someone must have done a thesis on this! ;-)

Toodle pippy!

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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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