Saturday, September 10, 2011

Extratropical Storm Katia, Tropical Storms Maria and Nate: September 10, Update A

Not much time to dilly dally at the moment!

Extratropical Storm Katia (or Post-Tropical if you go with the relatively new NHC name)
She is now at around 44.7N, 47.7N heading ENE at a very very rapid 53mph! This speed alone suggests she is extratropical. She’s been like this since yesterday, but is now officially an ex-Hurricane, heading towards the British Isles.

Winds are officially 80mph, central pressure is 954mb. I think she’s a bit weaker, but will still bring wind (gale force in some parts) and rain. The NHC have issued their last advisory on Katia, but say that those in the UK and northern Europe should get info from the UK Met Office (yay!) at Here’s their severe weather warning page:

I’ll keep following her for now… someone in the UK can send me a weather report (“raining, blustery, raining, tea break, windy, windy, raining, tea break, raining, windy, raining, tea break, windy…”) . Fun weather across the pond this week!

Terrance sent me this photo of Katia’s clouds at sunset (taken by Roydon) when she was visiting Bermuda.

Pretty sky! (I like clouds J). Thanks Terrance (and Roydon)!

Tropical Storm Maria
She’s really not a Tropical Storm but rather a low pressure depression. However the NHC are keeping her as such for now (just in case she changes her mind). They have discontinued all warnings. There’s no real circulation in this system, and although the winds are officially 40mph (central pressure 1007mb), that’s just to keep her at the TS classification (TS range: 39-73mph). They cannot locate a center, but are guessing it to be at 17.3N, 61.5N, with a similar guess regarding her direction and movement – NW at 15mph.

What I see is some circulation in the lower troposphere, right over the Windward Isles (a bit south of the official center), however, I cannot see an exact center either, and have not been able to for a few days. So I would agree with keeping her as a very weak Tropical Storm. She has room to move NW now because the high pressure that was keeping her on a westward track has eroded. There is a hefty band of convection though, because water temperatures are warm (a lovely 29-30 deg C). You can see this in the IR satellite image:

Tom on St. Thomas wrote yesterday that he’s expecting a “good bit of rain”. Yes indeed!

Tropical Storm Nate
They have downgraded their estimate on his intensity and no longer are forecasting a hurricane, quite rightly so. It looks like it wasn’t only the closeness to land that was suppressing him, but also dry air. He’s a weak TS, and official winds are 50mph, central pressure 1000mb. He doesn’t have a lot of convection, more cloudy with bits of rain (‘bits of rain’ = very precise scientific measurement ;-)), so I agree with keeping him as a weak Tropical Storm. As far as the vorticity (circulation) goes, he has as much as Maria, but he is a bit better organized so it’s easier to see the center, which is at around 20N, 94.2W (moving W at 6mph)... right towards a Mexico landfall tomorrow.

And that’s all I have time for at the moment… I have important things to do. Like finishing eating my yummy homemade British pancakes (not to be confused with American pancakes or French crepes) and British TV to watch! J More later 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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