Saturday, September 25, 2010

Tropical Storm Lisa and Tropical Depression Matthew: September 25, Update A

It's saturday today and nothing much is going on ... so I'm going to do a weekend thing and be lazy. ;-)
Tropical Storm Lisa:
She's currently at 23.7N, 28.4W and moving N at 12mph. She's too disorganized for me to see her center, so I'll go with the official word. Her winds are now 50mph (far more reasonable, in my humbly opinionated point of view ;-) ) and central pressure is 996 mb, making her a mid-sized Tropical Storm (range: 39-73mph). There is wind shear, not much convection (there are clouds, but not too much rain and thunder) and vorticity is strong only in the lower half of the troposphere - mid-size TS sounds about right. She's just bothering the fish and anyone who happens to be in that part of the Atlantic. I agree with the NHC assessment on her today, so this is all I have to say.
Tropical Depression Matthew:
He is currently at 17.4N, 89.4W and moving NW at 14mph. Winds are (apparently, huh) 35mph and minimum pressure is 1003mb. The forecast calls for him to slow down and become stationary over the Yucatan peninsula soon, and because he'll be over land he will weaken further and dissipate. As expected, the dissipation is slower than was forecast yesterday and has been pushed back from Monday to Tuesday afternoon. You all know my take on the reason for that - because his intensity was (and continues) to be underestimated. I would put him as a Tropical Storm now, given that he has strong vorticity in the troposphere (including a small amount in the upper troposphere) and he is still producing torrential rain and thunderstorms, despite being in an area of wind shear and over land. Also, he's a bit messy and disorganized (he could do with a proper filing system! ;-)) but he looks a little southwest of that location, in which case I can see him maybe continuing to move westward(ish) for longer than forecast instead of becoming stationary. I'll be looking out for the forecasted slowing down tomorrow afternoon. 
And that's it for my lazy Saturday. Enjoy the weekend! :-)
Ciao for now!
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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 was there and was going to "run away, run away" (Monty Python), I'll let you know.

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