Friday, August 27, 2010

Hurricane Danielle, Tropical Storm Earl & the Atlantic Blobette: August 27, Update A

Hurricane Danielle:
She's a lovely looking storm, and of course a big storm! She's been a category 4 (range: 131-155mph) for most of today, with max winds of 135 mph and a central pressure of 942mb. A plane was sent into the system this afternoon so these values are based on actual real-life in-the-storm observations, not just an estimate (if you missed it, see yesterday's update for that chit-chat). She's moving NW at 9mph and is currently located at 27.3N, 60.3W. The eye has a diameter of around 17-23 miles.
Although she's heading in a NW direction and looks like she's aiming for Bermuda, in the next few hours (maybe 12) we should see her start to move more NNW and then northward as she moves clockwise around a high pressure. Looking at the latest satellite images I'm almost certain she's started to make that turn and is moving NNW, but I have had a glass of wine so it could just be my eyes seeing things! As expected, Bermuda will still get a clip and is under a Tropical Storm watch. The outer bands (clouds only) have just started to reach them. Last I heard, this morning all was fine on the island. Not much wind. Preparations underway. All the normal stuff if a cat 4 hurricane is heading in your direction. And you're on an island.
Convection has decreased a bit, but I think that's just a cycle and it will pick back up.  Vorticity is very strong throughout the troposphere. Not much wind shear at the moment. Water temperatures over 29 deg C. For now, I don't see anything that will bring the intensity down. If anything, it may increase further. So basically we're waiting for her to take that northward turn! Any time now would be super.
Tropical Storm Earl:
Our next problem child. He's been a bit lazy and hasn't done much today but he might get some work done tomorrow and start to develop further, which is also what is forecasted. His vorticity is strong in the lowest half of the troposphere and I finally see it beginning to improve in the upper half of the troposphere. His current estimated center is around 15.8N, 46W and he is moving rapidly westward at 20mph. Minimum pressure is estimated to be 1003mb, with winds of 45mph (TS range: 39-73mph). He's still a bit of a messy blob (a slobby blob), which is why I say the center is an estimate - it's difficult to see exactly where it is.  
Wind shear is dying down. But there is still dry air on almost all sides that might reign him in a bit. Water temperatures are now 28 deg C, and he's heading into warmer regions with temperatures above 29 deg C.  He might clip the northern Leeward Islands when he gets to that side of the Atlantic. Some of them (St. Martin, St. Barthelemy) are already under a Tropical Storm watch. The forecast has him as a cat 1 hurricane in that general area (north of the islands) by Sunday evening.
Atlantic Blobette:
This has improved in circulation today, and the vorticity in the lower troposphere is rather decent. I can't quite assess the convection properly, because it's still quite far east - at around 10N, 25-30W. Not much more to say on this for today. The next name is Fiona.     
A bientot!
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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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