Saturday, October 01, 2011

Hurricane Ophelia and Tropical Storm Philippe: October 1, Update A

Welcome to October… only another TWO months of the hurricane season left to go! Ha.

Hurricane Ophelia
Officially she is at 29.5N, 62.9W, heading N at 21mph. Winds are still 120mph, so she’s a mid-level cat 3 storm (range: 111-130mph) and the central pressure is 952mb. It looks like she’s far enough to the east of Bermuda that they won’t get any hurricane level winds (74 mph or higher), but they will get tropical storm conditions. It looks like they have already had some rain from a rain band (according to satellite images). Hurricane force winds extend out to about 40 miles from the center.

I agree with the NHC on her forecast track:

Although she has a lovely eye (satellite images below) and excellent circulation, the convection is pretty low for a cat 3 as you can see in the IR satellite image (there is none of that really strong red or grey colouring that indicate really tall thunder clouds/deep convection), so it is possible she might actually be strong cat 2.

Last night the most important thing on Steve’s mind was: “ the Australian Rules Football grand final. Starts in about 3/4 hour. Collingwood play Geelong.” Sounds er… fascinating. ;-)

Tropical Storm Philippe
Officially he is at 24.8N, 48W, moving WNW at 9mph. Winds are still estimated to be 50mph, with an estimated central pressure of 1004mb. You’ll be pleased to know his official location today passes my quality controls, so I agree with the NHC on that. J I think he might be a tad weaker than 50mph, but it still means he is a weak Tropical Storm, so that’s all groovy.

His forecast track looks very silly at the moment, with an acute right turn in his track on Tuesday:

As I said yesterday, this is because the models are essentially basing this on him heading towards the largest low out there… Ophelia. There is a physical reason to do this and it’s not just a whimsical quirk of the models; It is because she will erode the high pressure he is stuck in. I don’t have the ability at the moment to say how much and how effective that will be by Tuesday, so for now, we’ll just keep watching him struggle to keep going. Although water temperatures are a lovely 29 deg C, and Philippe has more warm water under the ocean he is hanging out over than Ophelia does, he is facing considerable more wind shear in the atmosphere than she is, which is why he is struggling.

That’s it for now. More later!

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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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