Wednesday, September 06, 2017

Hurricane Irma and Tropical Storm Jose: September 5, Update B

Oh my goodness, what a day. Better get right to it methinks as there are storms a-plenty brewing!

Hurricane Irma
She is currently at 17.7N, 61.8W and is now definitely heading WNW at 15mph:
She is a big lady - around 300 miles from one side to the other and the eye is not wavering at all. She has hit Barbuda – as we can see from the satellite images above and this image I captured from Meteo-France’s Guadaloupe Radar, with Barbuda in the center of the eye:
The island is so small though that she is not really going to be hugely impacted – as I said earlier, she may drop from a super strong cat 5 to most likely a weak cat 5 (maybe a strong cat 4). She is currently on track to make ‘landfall’ on Anguilla and St. Martin on her way to the Virgin Islands (p.s. Dear Mr. Branson, please evacuate as many as you can, if you can, as that would be jolly helpful – including yourself! Oh, and if you would like to fund a technology development competition to get better tropical storm forecasts, please drop me a note – I can totally hook you up with that!!).

Irma’s winds are 185mph; not much change from earlier. She has a minimum pressure of 914mb, which has clearly dropped during the day. This still makes her an extremely strong cat 5 storm (strongest recorded winds!). Hurricane force winds (74 mph or higher) can be felt about 50 miles from the center (Antigua is also in this ~range now) and Tropical Storm force winds (39 mph or higher) can be felt up to 175mph from the center.

A cat 5 is anything over 157mph. It doesn’t matter how much over 157mph…

<Science Alert!> The Saffir-Simpson scale is the category scale for hurricane intensity. A category 5 is the highest level of intensity because the Saffir-Simpson scale is actually a scale of the amount of damage caused by different wind speeds - Herb Saffir was an engineer and Bob Simpson was a meteorologist. This is why each category is not evenly distributed in terms of the wind speed brackets (TS = 39-73mph; cat 1 = 74–95mph; cat 2 = 96-110mph; cat 3=111-129mph; cat 4=130-156mph; cat 5 => 157mph). So by definition (and I don’t mean to scare you!) a category 5 is catastrophic destruction, or total annihilation if you prefer. There is no Category 6 and there never will be because you can’t possibly get any higher level of destruction than this! <End Science Alert!>

I know there is a lot of concern (and concern-plus, and possibly a marginal hint of panic tinged with a feeling of ‘aaaaggghhhh’) in Florida (thank you to everyone who contacted me) given the projected track:
A note that there is currently a LOT of uncertainty in the forecast track at 4 days (Saturday) – it still about has 300-miles of wiggle room! This means she could go anywhere in that 300-mile cone. Please do not focus only on the center of that line. As for 5 days out, the track has around 450-500 miles of wiggle room. Actually, even on Thursday, the track has an uncertainty of around 150mph.

Also, between the Irma you see now and the Irma you may see in 2 or 3 days are the islands - depending on her path, if she interacts more with the islands she will be weaker. Unfortunately, they are still the only thing that will inhibit development at the moment because there isn’t any sign of wind shear picking up in the next day or two (at least) and the water will be toasty warm. We need to keep an eye on her track and whether it goes over a part of the Greater Antilles (Puerto Rico, Hispaniola, and Cuba in this case) which is, of course, going to create a right old mess. There is a small chance she will slow down again tomorrow for a bit, but that’s not a good thing for anyone in that general area so let's hope not! 

More practically for Floridians, I heard that people are evacuating from all across the southern half of the state and that many flights to the north are already booked. Airlines should really reduce ticket prices in these situations – for flights out to anywhere in the US! The toll roads have removed the tolls (thanks to Alison H. for this tidbit).

Personally, if I were in Florida, I would get ready but wait until around Thursday before evacuating so we have a better idea of where she is really heading. However, this takes us back to the reasons why people in Houston couldn’t evacuate – it’s a real problem not having a longer time for forecasts!

If you want to evacuate earlier it is always better to be safe. And above all, if your emergency managers tell you to evacuate, then please evacuate!! Right now though, we are so far out from knowing exactly where she will go, so if you evacuate, then I would drive north and inland because there are still a few possibilities of where she will go:
1.     If she goes to Florida and not towards the northern Gulf (which is still a possibility), there’s a chance she will then go up along the eastern seaboard in which case evacuating from Miami to Jacksonville may not be a good idea!
2.     But we don’t know yet if she will stay in the Gulf, so evacuating to somewhere like Tallahassee may not be good either because it is too soon to say if she will head in that direction!
3.     On the other hand, if she hits on one side of the state and cross to the other side, then evacuating inland to Orlando will not be great! (remember Charley?)

We will have a much better idea on Thursday.

Generally, something to remember: ‘run from the water, hide from the wind’ which means that if you are along the coast in a zone that can flood from storm surge, please evacuate. More deaths result from water than wind in a tropical storm. If you are inland and on higher ground, then hide.

Meanwhile, for those on the islands – we are all thinking of you and hoping for the best! Eugh, Double Eugh, and actually, Triple Eugh!!

Tropical Storm Jose
Ok, might as well as give you all the ‘fun’ information in one go! Jose has slowly improved in intensity during the day, and actually is now at 12.3N, 41.7W, heading W at 14mph. Winds are an estimated 50mph, central pressure is 1004mb.

I think he may be a bit stronger than this and will agree with the NHC if they upgrade him to a cat 1 hurricane tomorrow because there is a vorticity signal (circulation) in the upper troposphere. He’s currently following in his bigger sister’s footsteps for now… (sorry!). 

I’ll have more on him tomorrow. Time for a bit more ice cream and then a nap!

More tomorrow,

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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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