Friday, November 13, 2020

Tropical Storms Eta and Theta, and the Caribbean Blob: November 12, Update A

I heard from lots of you as Eta went by and today - I hope all gets righted as quickly as possible! It made landfall at around 4.20am today, about 5 miles north of Cedar Key, FL as a fairly weak Tropical Storm with winds of 50mph. Luckily for them the maximum storm surge was about 3ft above normal and occurred at low tide, so not as much of a problem as storms of times gone by. 

Tropical Storm Eta

But for a fairly weak storm it caused quite a problem, mostly water related as expected, which unfortunately resulted in a number of deaths in FL and in NC (from flash floods). 

It's now over the Atlantic at 32.3N, 79W, heading NE at a pretty quick 17mph.

Winds are now down to 45mph, central pressure is 1004mb, which makes it a very weak Tropical Storm (TS range: 39-73mph). There isn't really much of a storm - the convection is just from being over warm water. 

The storm has now pretty much merging with a front, which you can see from the vorticity maps. Here's the lower troposphere at 850mb: 

middle of the troposphere at 500mb: 

You can see the long stream of vorticity (circulation) along a northeast/southwest angle.

This is one storm name that will get retired - in addition to the havoc in the US, this is the same storm that hit Nicaragua (seems like weeks ago!) and Central America where, sadly but not unexpectedly, its flooding caused over 120 deaths, hundreds are still missing, and millions are severely affected in Honduras and other countries in the area. 

This will be my last update on Eta.

Tropical Storm Theta

Officially this is at 31.7N, 26W, heading E at 12mph towards the Canary Islands for the weekend (don't we wish we all were?), where it will hang out and dissipate. 

Winds are currently 60mph, central pressure is 993mb, which means it's a mid-size Tropical Storm. This one got some of it's energy from the atmosphere all along, so at the most I'd let it be a Subtropical Storm now, but even that's a little dodgy as the vorticity maps show that in the mid-levels of the troposphere the circulation is connected to a line of strong vorticity. There's no way that strong a system is purely driven with energy from water which is 22-23 deg C! 

Satellite imagery shows some circulation but very little convection, but we see this sort of thing in many winter storms (over cooler water temperatures): 

I think this will be my last update on Theta as well unless it does something wonky before getting to the islands. If you are out there, it'll be more of a windy thing than a water event. 

Caribbean Blob

You do know we have a few weeks before the statistical end of the Hurricane Season, don't you? ;-) SO....

... there is a blob which now has an 80% chance of developing into a storm in the next 48 hours. You can see it quite clearly in the vorticity maps - it has circulation in the lower level and is actually a little better structured in the mid-level compared to Theta. To me, this suggests it's already a Tropical Depression, and maybe even a weak Tropical Storm by now. The convection isn't quite there yet though:

This may be the future Iota... and hopefully it will just be an iota of a storm because one possible path is towards Nicaragua & Honduras! 

That's it for now. I'll be back when the next one develops. So, most likely 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. 

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