Friday, September 07, 2012

Tropical Storm Leslie, Hurricane Michael, and the Gulf of Mexico Blobette: September 7, Update A

Between tropical summer storms, dust storms and time travel, I just didn’t get the opportunity to write yesterday. This is my third time zone in three days! It would be much more convenient if I had a TARDIS! ;-)

Tropical Storm Leslie
I am pleased to see that the NHC downgraded her to a Tropical Storm this morning with winds of 70mph, central pressure 981mb. I am not sure about this central pressure and wind speed assessment – it seems like a really low central pressure for only 70mph winds (and they keep decreasing their estimate of central pressure but also decreasing the wind speed which is odd), but this was from a NOAA hurricane hunter plane.

I do agree with the wind speed estimate – I think that is close to the right range. She really was a border-line Tropical Storm/cat 1 hurricane yesterday, and her convection looks even more ragged today. As I said a couple of days ago, that dry air is doing its best, aided by its plucky side-kicks, ‘a very-little-bit-o-wind-shear’ and ‘cooler-waters’ (surface temperatures have decreased to about 24.5 deg C! – that’s almost a 5-6 deg C drop since she’s been there, which is really impressive). Here is the latest infra-red satellite image of Leslie:

She’s mostly just clouds (white and blue), with some rain (yellow) and some thundery weather (orange), but none of that really strong convection. The circulation is pretty decent throughout the troposphere, so if our superhero and it’s side-kicks decide to take a break she could still intensify a bit, but not too much methinks, and certainly not the cat 2 that was in the official forecast a few days ago.

Officially she is at 26.8N, 62.2W, and the NHC think she is stationary. I think she’s a little east of this at 26.8N, 61.8W, and is slowly creeping… yesterday the pressure fields changed (finally!) and she has a bit of wiggle room now to move northwardish (but not by much yet and she might get stuck again). The NHC have changed the timing and keep her pretty much stationary until Saturday, and she’ll pass the Bermuda area now on Sunday. I agree that she will pass east of the island, so it should be a fairly nice day on Bermuda after all. Maybe a bit breezy, but that’s just a minor challenge in the world of golf isn’t it?

Hurricane Michael
He’s still a pretty decent little hurricane, with a lovely clear eye. J Officially he’s at 31.2N, 41.1W, heading NW at 3mph. I think he’s at 31.2N, 41W, heading north or NNW. Winds are officially 105mph, central pressure is 970mb, which makes him a mid-intensity cat 2 storm (range: 96-110mph). I think this is an overestimate in wind speed. I’d put him closer to the 95mph range. Convection is not really as strong as one would expect in a cat 2. I saw they had him as a cat 3 at one point a couple of days ago. I think that was an overestimate as well.

Gulf of Mexico Blobette
As expected, this blobette is still moving southwestwardish, and really isn’t anything significant. There’s a bit of circulation in the lowest levels of the troposphere, but nothing in the middle levels. She’s just a blobette – we have more action when a front comes through! I’m not going to write anything else about this unless she does something interesting.

Must run… my <ahem> glamorous <ahem> Hollywood life is beckoning, but I’ll be back as a science geek later though! ;-)


Blogs archived at
Twitter @JyovianStorm
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.

No comments: