Wednesday, September 05, 2012

Tropical Storm Leslie, Tropical Storm Michael, and the Gulf of Mexico Blobette: September 4 (well, early 5th now), Update A

Goodness me, what a long work day! It is now 2.25am in the time zone I am visiting for A day, and 3.25am in my normal time zone! But this is the last thing I need to write before sleepytime…. If I fall asleep mid-sentence, you’ll knozzzzzzzzzzz! (reminds me of “ARTHUR:  Look, if he was dying, he wouldn't bother to carve 'aaggggh'. He'd just say it! MAYNARD:  Well, that's what's carved in the rock! GALAHAD:  Perhaps he was dictating.” Monty Python J).

Tropical Storm Leslie
Leslie is obviously counting the fish in the middle of the Atlantic … she’s now moving at a whopping 2mph in a NNW direction (towards Bermuda). She is well and truly stuck in a region of high pressure. We’ve had some rather memorable stalling storms (Wilma in 2005 over Campeche comes to mind), but I can’t remember when a storm was surrounded for so long by high pressure! The current forecast keeps her in the same area until Friday, and then she’ll start to move. At the moment I’m going to agree with this scenario because the data I have still only shows her moving slowly/stalling, and n'owt else.

Her center is at 25.2N, 62.8W. As you can see in this infra-red satellite image she is still big, but if you compare this to yesterday’s image her convection has decreased (less red!):

She is wearing out her welcome! Also, now that the convection has backed off a bit it looks like dry air is entering the system. Wind shear has decreased, although there is still some impacting the eastern side where the clouds are streaming off. Winds are 65mph, central pressure 994mb. This makes her a strong Tropical Storm (TS range: 39-73mph). Her intensification (or lack of) depends on the atmosphere in this case, not so much the ocean (although water temperatures of 29 deg C  are enough to keep her going). There is good circulation in the lower troposphere and there is actually very good circulation in the upper troposphere – enough to consider her a stronger storm (borderline cat 1 actually), but that dry air is really doing its best!

Tropical Storm Michael
Really? Wind shear decreased since yesterday which really allowed him to tidy his act up and develop into a storm. But he’s even smaller than Captain Kirk… you need a magnifying glass to find Michael! He’s stuck in the same high pressure as Leslie, and is stationary at 27.4N, 43.7W. Water temperatures are 27 deg C, with water warmer than 26 deg C in the upper 50-75m (about the same as his big sister to the west). I agree with the NHC analysis on this one. Winds are 50mph, central pressure 1005mb. He’s pretty weak still and he won’t really impact anyone (on land).  More on Michael tomorrow.

Gulf of Mexico Blobette
Hmm… so I’m in Pensacola. Writing from under this blobette. In classic alternate reverse universe fashion, it is coming ‘off’ the mainland US and moving into the Gulf. How interesting! The question is whether or not this is some sort of remnant of that pesky Isaac. It looks like it is part of a front that stretches across the eastern US, that was, in turn, fed by Isaac… so it could be that this is a bizarre offspring! It doesn’t have too much convection (because it rained here all day), but there is some circulation in the lower troposphere (which is still attached to that front). I am not sure what anyone is making of this, but the NHC give it a 10% chance of developing. It may just fizzle out… I’ll know more tomorrow! (an obvious thing to say really).

Sleep…sleep… (By the way,thanks for the RTs everyone! J)

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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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