Wednesday, September 07, 2011

Hurricane Katia and Tropical Storms Maria and Nate: September 7, Update A

<warning: heavy sarcasm advisory> Today we shall all play ‘How Not To Be Seen’ (a la Monty Python). In these satellite images (both visible and infrared) from this evening, there are THREE Tropical Storms/Hurricanes:





Can you spot them all? In the middle of the Atlantic is Tropical Storm Maria, near Bermuda is Hurricane Katia. And yes, for those of you with a sharp eye (or those of you who have seen the latest hurricane map), in the Gulf is Tropical Storm Nate… who is cunningly disguised as a low pressure FRONT. And how do we know this is what he is disguised as? Because there are clouds extending in a linear manner from Central America to Florida. <end of heavy sarcasm advisory>

<mutter grumble mutter mutter>

Hurricane Katia
She is currently officially at 30.8N, 70.0W, heading NNW at 13mph. Winds are 80mph, central pressure is 982mb.

At least they downgraded her earlier today to a mid-level category 1 storm (range: 74-95mph), so I think they finally have the right intensity. She is making that curve towards the North as expected.  There is still a lot of dry air on her western side, which continues to inhibit development. But as you can see from the satellite images, Bermuda is on the east side (you might need to get your magnifying glasses out to find the island). It is unlikely that she will get too much stronger than this, given that she is moving north over cooler waters (although wind shear is still looking a little light), but Bermuda will get something other than their clear sunny skies.

Current conditions on Bermuda are Cloudy and Breezy… umm… weren’t they two of the dwarves?

Earlier today I heard from Steve on Bermuda. We had a serious discussion of the deteriorating weather conditions on the island:
S: “it's a bit bloody breezy now… Reckon 50/50 as to whether (pun intended) the BA flight will leave tomorrow night.”
J: “Haha... nice pun. :-)  It's going to get a bit breezier... Are you all set for the weather?”
S: “yes all set for the weather. That's why we moved tomorrow evening's golf game and had it last evening. I'm no fool!”
J: “I expect you'll be having a BBQ tomorrow evening instead?”
S: “are you kidding! We have the hot air balloon already to go. We're taking parachutes just in case though.”
J: “That's terribly prudent of you.”
S: “well we're not so silly as to through caution to the wind.”

If anyone would like a Hot Air Balloon ride over Bermuda tomorrow, please contact Steve. ;-) I’m hoping for more updates from Bermuda tomorrow.

I expect her to continue making that forecast turn to the north, and remaining a cat 1 storm as she skirts around Bermuda. Interestingly, the forecast is for her to be an Extratropical Storm as she get to the UK on Monday afternoon. Given that she is a mid-level cat 1 now, there is a good possibility that she’ll be weaker than that. It may be a bit breezy in Scotland… but they won’t notice the difference up there anyway.

Tropical Storm Maria

From The Sound of Music (I did warn you all yesterday):
“How do you solve a problem like Maria?
How do you catch a cloud and pin it down?
How do you find a word that means Maria?
A flibbertijibbet! A will-o'-the wisp! A clown!”

As expected, TD 14 turned into TS Maria. Currently she is at 13.2N, 44.2W, zooming along generally westward at 23 mph. Winds are 50mph, making her a weak-to-mid level Tropical Storm (range: 39-73mph), central pressure 1002mb.

She is too disorganized for me to be able to see where her center of circulation is, but it looks like it is north of the official location. The convection is trying to sort itself out, but for now it is not very strong because of wind shear in this area. There is some circulation in the lower half of the troposphere. I would say she is a weak level Tropical Storm for now. There is no lower level convergence or upper level divergence to speak of, and the wind shear looks like it will get stronger, so I think she might weaken a bit further.

The forecast is for her to continue westward and then curve WNW and NW, through the northeastern Caribbean islands, and up towards the eastern seaboard. I can see her continuing westward for now because at the moment there is an area of high pressure that extends into the Caribbean. Until that erodes, I think she’ll carry on westward. However the track models have been pretty good with Irene and now Katia (all the girl name storms ;-)), and they are taking this one to the NW – anywhere from the eastern US to Bermuda. It wouldn’t hurt to keep an eye on this one, but I don’t think she’ll be very strong by the time she gets to the Caribbean.

Tropical Storm Nate
<cough><mutter><mumble><cough>

I can’t believe they named this! There is some weak vorticity (circulation) in the lower troposphere which is connected to vorticity across the Gulf. This corresponds to the convection you saw in the satellite images. There is no upper level divergence and very little lower level convergence, so this doesn’t have a good tropical storm structure at all.  Could it be that this is a front, not a tropical storm?

Even the NHC know this:

“… OVERALL THE SYSTEM RETAINS A SOMEWHAT BAROCLINIC APPEARANCE DUE TO ITS POSITION NEAR THE SOUTHWESTERN END OF A FRONTAL ZONE”

They have him as almost stationary over the Bay of Campeche, and forecast him to become a hurricane by Friday, with landfall in Mexico (on the western side of the Bay) on Monday evening. He is officially at 20.4N, 92.5W, moving E at 2mph. Winds are 45mph, central pressure is 1003mb. Officially he is barely a Tropical Storm. According to the NHC, their two satellite estimates of intensity have winds below Tropical Storm strength, but A SINGLE ship reported winds in ONE location that were a little stronger, so they are taking that as their basis! WHAT! A SINGLE Instrument! Really?!? (And you know that ships report stronger winds in fronts too by the way, because there are areas of windy weather in low pressure fronts too). I’m going to walk away from Nate for now and revisit him tomorrow. Maybe he’ll be something that walks and talks like a grown up Tropical Storm by then.

Speaking of tomorrow, I’m traveling again. Back to Georgia… to the delightful city of Savannah this time (did you know that life is like a box of chocolates there? Sweet, but melted and gooey in the heat ;-)). I’ll check in when I can!

Good luck on Bermuda.
Night night,
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm

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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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