Monday, July 31, 2017

TS Emily: July 31, Update A

A very quick update for now. TS Emily is at 27.6N, 82.8W, heading E at 9mph. Central pressure is 1005mb, winds are at 45mph, making her a very weak TS.

Strictly speaking TS Emily is not actually a Tropical Storm but is part of a front that extends from the Gulf, across Florida, and into the Atlantic.

Here is the circulation field (vorticity):

You can see the long line of yellow/orange/red that extends from the Gulf and to the northeast which is the vorticity signal of a Low Pressure Front, and the’ ‘L’ which indicates where TS Emily is. This is the same Low Pressure Front that dumped a bucket or two of rain over the northeastern US seaboard a few days ago. 

If you look at the satellite imagery, the infra-red shows a lot of rain – definitely expect a lot of rain! Get those wellies and brollies out!

If you look at the visible satellite imagery, you can see the circulation just off Tampa Bay… but as this is a front, if you look at other places along that line, you will also see some swirling circulation – for example, at around 30N, 79W:

A few hours before she was named, the NHC also thought it unlikely she would become a fully-fledged storm, giving her a 20% chance of formation. From a scientific/weather perspective, I don’t think she should be a named storm at all and will, yet again, make the annual records incorrect on how ‘active’ this year was (Grr). But I suspect they named her under other considerations - financial, political, or possibly social/emergency response perspectives (especially likely as she is close to a major population) to warn residents of potentially heavy rain and flooding.

So yes, I would expect water - I know some places in St. Pete flood under a light drizzle (e.g. Shore Acres) - but not too much on the wind front. To the south of her center (and under that front), I would expect more water - there is a lot of rain (as you can see in the satellite images) and along the coast she is pushing water onto the shore.  To the north, she is pushing water off, so sea levels will drop. To look at the nearest sea level data, go to NOAA's Tidesonline:, click on Florida and pick the station you want to look at. The St. Pete area is currently around 1 ft above normal, to the south there are places where it is around 1.5 feet above normal (e.g. Ft. Myers) and to the north, there is no change (e.g. Cedar Key).

Must run, but more later!

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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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