Tuesday, September 21, 2010

'Hurricane' Igor, Tropical Storm Lisa, and the Caribbean Blob: September 21, Update A

Let's see, it's September 21 and we have a new storm, Lisa. On August 21, Danielle was spinning up but not named. D, E, F, ... <a few more letters>... K, L. That's 9 storms in the past month. I don't think that's a record, but phew! I can't remember what it's like to just plonk oneself down in front of the telly... maybe because I haven't had a TV for a couple of years. Ok, I can't remember what it's like to just plonk oneself down in front of a blank wall....
Hurricane Igor:
Eeek... Igor's gone postal!!! Oh wait. Sorry. That's not quite the NHC headline. I mis-read. Oops. The actual headline is: IGOR BECOMES POST-TROPICAL. He's at 49.3N, 51.7W and in Canada (Newfoundland), so yes, I agree he's not 'Tropical'. I learned that Canada wasn't in the tropics when I was about 6 and it's a relief to know that piece of knowledge is finally paying off. ;-) Winds are 80mph, central pressure is still a very very low 950mb, and he's moving NNE at a rapid 39mph, but all of that is because he's actually part of a low pressure front now and hence an *extratropical* storm. Hurricane force winds (greater than 73mph) can be felt up to 80 miles from the 'center' and tropical force winds (39mph or higher) can be felt up to 520 miles from the center. Although he's still marked as a hurricane and then Tropical Storm until the end of this week (when he more-or-less reaches the Arctic !!), the NHC have stopped their advisories on this system because he's no longer Tropical... and therefore not topical. ;-) That's fine with me. If anyone wants to know what's going on 'up north' in more detail than my assessment of 'a bit of rain with very windy weather', visit the Canadian Met Service (http://www.weatheroffice.gc.ca/canada_e.html). This is my last entry on Eager Igor. Oh happy day!
Tropical Storm Lisa:
We have another named tropical storm. I am not surprised, and neither should you be. *We* knew it was a Tropical Depression for over a day. Lisa is in the eastern Atlantic, and has estimated winds of 45mph and a central pressure of 1002mb. She's almost stationary, even though officially she's 'moving' (crawling) in a northward direction at 2mph. She's centered at 18.3N, 31.6W. She's not very well organized so I'm not 100% convinced that is the center of circulation. Looks to me like it could be anywhere between 17.5-18.5N and 30-32W, but I'll go with the official word for now. She has a lot of vorticity in the lowest half of the troposphere - definitely the signal of a strong Tropical Storm, if not the start of a hurricane. Certainly stronger than her current official estimated strength. Convection has been waxing and waning all day though. Despite a small vorticity signal in the upper troposphere (further indicating potential hurricane development), until she gets her convection organized she won't get much stronger.  The NHC forecast has her as a hurricane in just over a day. I can see that, provided the convection is there. The long term track is all over the place - it's difficult at the moment because she's not really moving anywhere and she's not very strong. I'll look into my tea leaves tomorrow.
Caribbean Blob:
This blob has been raining and thundering all over the eastern Caribbean for a couple of days, and today it finally began to get its vorticity sorted out. At the moment there's some weak circulation (vorticity) in the lowest levels of the troposphere, but nothing at the mid-to-upper levels. It's moving westward at 15mph and is really close to the South American landmass. We'll see how it develops. I don't think we'll see too much tomorrow but I'll check in with an update on it anyway. The next name is Matthew.  
That's all. Yes, a nice and easy day! There's even time for a relaxing cup of tea and a nap. ;-)
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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