Sunday, October 02, 2011

Hurricane Ophelia and Tropical Storm Philippe: October 2, Update A

I had a very nice weekend, and I understand that it was a breeze on Bermuda too (puns always intended ;-)). Steve on Bermuda says they didn’t get much of anything (“rain and a squall, but nothing of note”) as Ophelia, then officially a strong cat 3/cat 4 storm (!!), went by. I am not 100% convinced that she went up to a cat 4. But I am glad dinky little Bermuda was not too dashelled!

Hurricane Ophelia
At the moment she is officially a cat 1 storm (range: 74-95mph), with winds of 90mph. This might be a slight overestimate, because she doesn’t have an eye and has fairly weak convection, but I’d agree with a cat 1 status.

As you can see, the IR satellite image shows weak convection and the lack of an eye. She is currently at 42.4N, 59.8W, heading NNE at a rapid 33mph. Central pressure is 967mb. I agree with the forecast track which will take her to Newfoundland tonight/early tomorrow.

<science alert> In this case, I would say that although she is moving forward at a rapid pace, she is still a tropical storm. I have not always agreed with the assessment of a fast moving storm being tropical. The reason she is moving forward at such a rapid rate is because there is a region of high atmospheric pressure to her right and a region of low atmospheric pressure to her left, and she is caught between the two. Normally, storms only have the high atmospheric pressure (the Bermuda/Azores High) to move around, which is why they move at a nice stately pace in a clockwise manner around the Atlantic (my earlier blurb on the Bermuda/Azores High and its effects on storm track: However, at the moment Ophelia has a region of low atmosphere pressure to her left. In the northern hemisphere, things move anti-clockwise around low pressure systems. So essentially, she is being pushed by both the high and the low – it’s a double effect, which means she’s zooming along there. <end of science alert>

Tropical Storm Philippe
The force is strong with this one, but so too is the wind shear! He has circulation throughout the troposphere, and it is as strong as Ophelia’s in the lower levels. But he is under some considerable wind shear, so although he is trying and trying, he hasn’t yet managed to get to hurricane strength. He was close yesterday, when they increased his winds to 70mph, but the winds are back down to 50mph now. He is currently at 26.2N, 53.1W, officially moving WNW at 12mph (it looks like he’s actually moving W or WSW). Central pressure is estimated to be 1003mb. The convection is all on the south/southeast side of the center. It looks like wind shear will remain pretty decent, so it seems unlikely he’ll be a hurricane any time soon. The forecast track still has him making a sharpish right turn on Tuesday/Weds:

This is a likely scenario, but the data I have is not good enough for me to be able to determine that for myself. The reason this is likely is because that low pressure that is to the left of Ophelia is moving eastwards and so the ‘plan’ is that it should make room for Philippe to turn to the NE quite quickly once it gets into the Atlantic.

That’s it for now. Time to get ready for a fun-filled work week ahead! Woo-hoo.

Blogs archived at
Twitter @JyovianStorm

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.

No comments: