It's a busy travel day, so that means lychee martini day. Obviously. Our Constellation of Storms is still in place...
And from the satellites, this looks like:
TS Florence
Florence is currently officially the strongest of the three, with winds of 70mph, which means she's close to being back to a cat 1 hurricane (cat 1 range: 74-95mph). Her central pressure is 989 mb. She's currently at 24.6N, 54.7W, heading W at a very slow 5mph.
She's moving slowly because there's a high pressure in front of her that is slowing her down (it's like climbing up a hill - and I just got back from walking around Atlanta, so I know what that's like!). And she's moving W because she's skirting a high pressure area to the north of her. I know her forecast track looks scary:
You guys in Georgia and the Carolinas should all be ready as it really is waaay too soon to say quite where she'll go. I agree with the ~1 day forecast on the track at the moment, but I don't have the data (because we don't measure it) to be able to say what it will look like beyond that (and although I'm on travel, I'll check in once a day somehow as you are my peeps!).
In case you are wondering which one she is when you look at the satellite images, she's the tiniest of the swirling masses - the one that's around the same latitude as southern Florida. I know it doesn't look like she's the strongest of the three, but officially she is because a plane flew in and got some of valuable data, and those are the winds that the NHC have deemed her to have. Please note, a plane has not flown into the other two storms as they are too far away - this will feature later in this blog (spoiler: I really disagree with the intensity they have for the other two).
Let's look at her structure - the circulation (vorticity). Here's the vorticity (circulation) at 850mb (lowest level), 500mb (mid-level), and 200mb (upper level):
You can clearly see that the circulation is good for Florence in the lower half of the troposphere (up to 500mb), but there isn't a good defined feature in the upper troposphere, which indicates that her structure isn't quite so strong as a hurricane yet, so she is still definitely a Tropical Storm. For those who are taking a sneak peak at the other two storms... which one do you think is the strongest?
TS Isaac
He's officially a fairly weak TS with winds of 50mph (TS range: 39-73mph), central pressure 1002mb. He's currently at 14.4N, 37.5W, heading W at 8mph. I think he's actually around the same intensity as Florence and I would place him as a very strong TS/borderline cat 1 hurricane at the moment. His forecast track is currently westward:
The good news is that he is about to head into an area of very dry and dusty air - the Saharan Air Layer (the orange area in the image below) - which will keep him in check:
Although the official forecast says he'll be a hurricane in a couple of days, I'm not sure he's going to survive the crossing across the Atlantic if that forecast track holds true. This is really an interesting case because we'll see how much of an influence the Saharan Air Layer has on a storm (says the science nerd voice in me ;-)).
Ok, time for another Lychee Martini... so much to talk about!
TS Helene
Officially Helene is a mid-sized TS with winds of 60mph, central pressure estimated to be 999mb. She's at 13.2N, 22.8W, heading W at 13mph. I really disagree with the estimate on her intensity - I think she's clearly a cat 1 hurricane, possibly a border-line cat 2 storm actually. You can see from the satellite imagery that her convection is pretty robust. She also has the best 'outflow' of the three - meaning the cloud formation around the central strong convection is very good. But above all of that, she actually has a robust circulation (vorticity) at all levels of the troposphere. However, because we don't have data from inside the storm itself, the satellite-derived wind estimates place her as a mid-size TS. Sigh. This is one of the area's that we (at XPRIZE) are currently designing a prize around... if you can't afford planes and the storms are far from the coast, but that is the best data and really improves the forecasts, how do you get data from inside any storm, anywhere in the world?
Her forecast track is:
Currently she's bothering the Cabo Verde Islands with some rain and a 'bit of a breeze'!
Ok, better run... apparently they won't hold the plane for my updates! ;-)
Toodle pip!
J.
Twitter: jyovianstorm
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DISCLAIMER:These remarks are just what I think/see regarding tropical storms. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast. This is not an official forecast.
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