Tuesday, August 31, 2010

Hurricane Earl and Tropical Storm Fiona: August 31, Update C

Hurricane Earl:
My, but Earl is a big boy, isn't he? The NHC seem to have kept him as a cat 4 storm with winds of 135mph (cat 4 range: 131-155mph) even though he lost an eye. I don't think I've seen a cat 4 with no eye before. Personally, I think he decreased in intensity for a few hours there, but is getting back up to cat 4 level now. It looks like there were two reasons for the decrease. First, his southern edge was interacting with both Puerto Rico and Hispaniola. And second, he has been experiencing wind shear from the southwest. You can see a band of clouds streaming off to the northeast in satellite images of Earl.
He is currently at 22.5N, 69.1W, with a central pressure of 940mb and max winds of 135 mph. He's now moving NW at 14mph, and hurricane watches have been issued for a portion of the North Carolina coast. The new definition of a hurricane "watch" (for the 2010 season), by the way, is that hurricane conditions are expected within 48 hours - the new bit is that the lead time has been extended. Whether or not his center clips the Cape Hatteras region, other parts of the state will get some windy weather. At the moment hurricane force winds extend out 90 miles from the center, and Tropical Storm winds can be felt up to 200 miles away. And he still has to get to that Gulf Stream. As for convection. Yes. Lots of it - thunder and lightning and possible tornadoes in parts of the storm.
At his current location, water temperatures are over 29 deg C, with 26.5 deg C temperatures in the upper 75-100m of the water column. The vorticity in the atmosphere is quite impressive... the upper troposphere has circulation comparable to a strong Tropical Storm near the surface (where vorticity is usually greatest). So still a major storm and one that has a tenacious hold, and I don't think the wind shear will do much to change that. 
From Tom J. on St. Thomas, sent around 5.30pm his time:
"We will not have electrical power for a few days till they clear many downed trees, limbs, on top of some of the wires all over the island.......a few poles are down, several transformers blown...........we got off easy with this storm considering that it went to a cat 4 so fast..........damm lucky."
I assume those in NC are preparing. As I said at some point today, the rest of the states should also be getting ready to be getting prepared... (ok, it's late over here, that sentence makes sense in my head! ;-)). 

Tropical Storm Fiona: 
It doesn't look like we'll see the Fujiwara Effect any time soon. Earl kept pushing Fiona away today. He probably didn't want to share his chocolate bar. Awww. She is looking quite blobette-like again, and I agree with the plane that went in and could barely find a Tropical Storm. Although there's a fair bit of convection (heavy rain and thundery weather), her circulation seems to be east of that. And although there is some circulation in the lower levels of the troposphere, it is west of the circulation in the middle of the troposphere (all these easts and wests - very confusing, no? ;-)). The bottom line is that they indicate (to me anyway) that some sort of shearing has occured from the north and west at some levels in the atmosphere, and I'd say that was Earl's fault.
She's 'centered' at 16.8N, 58.7W (it's tricky seeing an actual center in the midst of the blobetteness that is Fiona). She's moving WNW at 20mph, and the convection will soon reach the leeward islands. Wind speed is kept at 40mph (just so she can still be called a TS, even if she isn't really one), with a central pressure of 1006 mb. She's also over water of 29 + deg C, with warm water of over 26.5 deg C in the upper 100m. At this rate, she might dissipate once she's reached the islands. Wouldn't that be nice. 
And now for something (almost) completely different: (Monty Python)
OK... so I'm travelling to another planet (Atlanta, Georgia) tomorrow. I was hoping that no-one would notice if I didn't write anything this week. Bother. I thought it was a good plan. With hindsight, maybe not the best idea to try it out in September though. Oops. ;-) Anyway, with exasperating Earl out there and with friends and readers in a number of states on the eastern US seaboard, I will activate some form of interplanetary communication at least once a day to chat about whatever is out there. Don't be surprised though if you see random sentences about aliens wandering around looking for a lift (er... elevator). ;-)   

Night night!
Blog archives at http://jyotikastorms.blogspot.com/

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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