Monday, September 14, 2020

Hurricane Paulette, Tropical Storm Sally, Tropical Depression 20, and assorted Blobs and Blobettes: September 13, Update A

Hmm... Seven rings... anyone got the One Ring to Rule Them All? That would be really 'handy' these days. ;-) (all puns intended).

First, the one's I'm ignoring today... 

- Rene was SO yesterday's news (for anyone called Rene - it's not you, it's me ;-)). 

- The Gulf of Mexico blob (yellow) is still hanging out with a 10% chance of development. There is some circulation but no convection, and the circulation isn't very well developed in the lowest levels of the troposphere. 

- The NHC say that the Blob over Africa has a 0% chance of developing in the next 48 hours... I really think they like that yellow colour - it's a happy colour, isn't it? We could all use a dose of happy yellow. 

- The Atlantic Blob has a 70% chance of formation. It's still connected to TD 20 as far as the vorticity (circulation) goes so it's not quite there yet. There is some convection, but as we have other storms closer to land, I'll punt on this one until tomorrow. 

There, that leaves only three out of seven now.

Hurricane Paulette

She's currently at 31.4N, 64.0W, heading NW at 13mph.

Her outer bands have already reached Bermuda (that little white dot to the northwest of the storm - blink and you'll miss it) and her eyewall will be there soon. Here's a satellite image from earlier today.

She's currently a mid-level cat 1 storm with winds of 85mph, central pressure 976mb (cat 1 range: 74-95mph). The dry air is having some impact in keeping her intensification a little in check and has taken a bunch out of her in terms of her convection which is a lot less than yesterday, as you can see in the imagery below (which is more recent than the image above):

The eye is not well formed and that dry air continues to get pulled into the system. 
The weaker convection will help in terms of the impact of the storm, although it will still be quite wet and windy and there will be some thundery weather with possible tornadoes. The NHC think she'll intensify to a very strong cat 2 in the next 12 hours, but I am not so sure given that she's struggling a little now, has still to fully interact with Bermuda, and there is some mid-level shear ahead of her. But that intensification should (hopefully) be after the bulk of her has passed by Bermuda. Stay safe out there my friends!

Tropical Storm Sally

Sally is at 28.2N, 86.2W, heading NW at 8mph and landfall is still on Tuesday, although her center was a little off and so the track may shift to the east (towards Alabama) from the one in this forecast... 

She is now a mid-sized Tropical Storm with winds of 60mph, central pressure of 996mb (TS range: 39-73mph). 

She is over warm water (warmer than 29 deg C) and the wind shear has vanished, and we can see that in the satellite imagery as she transitions from something that looks like a soggy mess to something that is definitely looking like she's just had a couple of strong beverages:

So she may be making landfall on Tuesday, but her rains and thundery weather will be affecting the northern Gulf coastline, especially Florida and Alabama, starting well... now. She will get stronger as she slowly moves north without the wind shear and with warm sea surface waters. The NHC expect her to be a cat 1 storm on landfall with winds of 90mph.

Moorings on the West Florida Shelf that are operated by the University of South Florida and are part of the Southeast Coastal Ocean Observing System (actually, the same moorings I used to get my PhD data a <ahem> "couple" of years ago <ahem>) showed a dip in pressure to 1005mb and wind speeds over 35mph as she passed near by earlier today. As an aside, I have to say, it's pretty cool to be sitting in smokey Los Angeles and to still be able to look in on data from moorings that were so pivotal in my being here! :-)  

Speaking of data, I mentioned some data being gathered under Hurricane Laura a couple of weeks ago. That effort continues and there are two underwater vehicles (gliders) currently in the Gulf measuring the upper ocean temperatures that will be in the path of this storm as well as she passes overhead. This sort of data will help scientists to work out some of the dynamics and feed into improving the forecast models in the future. You can see the glider locations on the map on this page:

For those of you along that northern Gulf coast - more than anything, it's going to be very wet over the next few days! 

Tropical Depression 20

He is still officially a TD and is currently at 13N, 39W heading WNW at 15mph. 

Winds are 35mph, central pressure is estimated to be 1006mb, which makes him not quite a Tropical Storm yet. I think this is an underestimate. His circulation is quite strong throughout the troposphere, although it is still connected to the Atlantic Blob at the lower levels. His convection has also picked up... 

I would consider him a Tropical Storm at this point. 

Anyone found that One Ring yet? 

Until tomorrow!


Twitter: jyovianstorm

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 

No comments: