Wednesday, August 31, 2016

Hurricane Gaston and Tropical Depressions 8 and 9: August 30, Update A

So much going on, but not enough time to cover it all! I need an XPRIZE in time travel... or even better, I'll settle for the TARDIS XPRIZE... then I won't ever have to pack again either (which is next on my list for this evening). That would definitely save oodles of time! :-) 

Hurricane Gaston
He's been fluctuating in intensity and is now a major cat 3 storm again, with winds of 120mph, central pressure of 956mb (cat 3 range: 111-129mph). He is currently at 32.9N, 50.9W and is heading ENE at 10mph:
I do agree with NHC's cat 3 assessment, but I have to say, there is something weird about this storm... for a cat 3 storm, he has an unusual and remarkable persistent eye (for at least 7 hours)! There is usually a little more variability. Impressive... just like the Disney song said! ;-)

He is moving over temperatures of 27-28 deg C, with only the upper ~25m warmer than 26.5 deg C. However, there was very little wind shear until the last few hours (you can see this in the satellite image as he changes from being more circular to being a little more elongated), so it's not too much of a surprise that he intensified. 

He is still on track to reach the Azores on Friday. Get ready out there!! 

Tropical Depression 8
This blob is now moving away from the eastern US coastline, as predicted. He is currently over the Gulf Stream and because it is a region of warm water that extends deeper into the ocean than the general surrounding area (around 75m of the upper water column is warmer than 26.5 deg C), his convection has increased as expected:
The vorticity maps (circulation) show that he has strong circulation in the lower troposphere, but the mid-tropospheric circulation is not well developed, which means he is still not really a Tropical Storm. So I agree with the NHC keeping him as a TD (for now).

Tropical Depression 9
This is the one I've heard the most about from you today! First, let me remind you about the words of wisdom from the Hitchhikers Guide to the Galaxy: "A towel is the most important item a hitchhiker can carry"... er... no, I meant "Don't Panic". ;-) (although I don't want to diminish the importance and versatility of towel). 

As I thought, this blobette did move farther west, so her entire track forecast has now been shifted slightly northward. This makes a lot more sense to me.  
Her winds are still at 35mph, central pressure is 1004 mb. She is currently at 24.3N, 88.1W and she is heading... nowhere. Just like Gaston a couple of days ago, she has essentially stalled. The nominal movement is W at 1 mph, which doesn't count for beans. 

Here are her latest satellite images: 

She is still a little messy so it is hard to see a clear center of circulation, although for the first time in days, I can see an approximate center in the same place as the official center location - 24.3N, 88.1W.

Here are the vorticity (circulation) maps for three levels in the troposphere - lower, middle, and upper:

First, there is no signal in the upper troposphere, which means that she is nowhere near being a hurricane. 

Second, and more interestingly, the lower level vorticity (circulation) is now connected to an area already over Florida - this pattern is actually more like a front than a storm! The vorticity in the mid-level is not looking very well defined either. Overall, this does not have the circulation patterns of a tropical storm! Meanwhile, to see the signal of a strong tropical storm, you can also look at the circulation that Hurricane Gaston has. Can you see the well defined, red circular pattern in all levels of the troposphere? - that's a hurricane! 

This Gulf of Mexico blobette is over warm waters - temperatures warmer than 29 deg C. But Florida has put up it's force fields (well done Florida!) and wind shear is increasing between this storm and the Florida coast, so if she turns in that direction, she will be facing increasing wind shear:
(increasing wind shear is marked by the yellows and reds on this map). 

The track currently takes her into the Big Bend area by Thursday evening. This is possible, although she may move a little more west than that position as well. Actually, the Florida panhandle and Alabama folks should also have their bottles of wine, ice cream, and other supplies ready. As I mentioned before, a stationary storm's future track is harder to predict! 

Overall, with wind shear building, it doesn't look like she will intensity too much once she starts to get closer to the coast. 

Tomorrow, I am on an interstellar journey ... I'm traveling to another planet where nice friendly aliens abound. :-) I'll try and post an update tomorrow if I can! 


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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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