Tuesday, August 07, 2012

Hurricane Ernesto and the Atlantic Blob: August 7, Update A

Hurricane Ernesto, a mid-strength cat 1 (range: 74-95mph) storm with winds of 85 mph, is making landfall at the very southern end of the Yucatan region of Mexico as I write this. Here is a satellite image of his convection:

The red area indicates very strong thunderstorm and tornadic activity, the gray is very very very strong thunderstorms with a lot of tornados. <Rant alert> (too many exclamation point alert) They finally got around to upgrading him seven (7!!) hours ago to a hurricane in the 2pm advisory, after noting just three (3!!) hours earlier that the pressure had dropped to 989mb! Apparently the planes didn’t find winds strong enough at that point in time to warrant calling him a hurricane so they speculated (!!!) that maybe the wind field had increased in size which would account for weaker winds and a lower central pressure!! (From the NHC: THE AIRCRAFT DATA SUGGEST SOME EXPANSION OF THE INNER WIND FIELD...WHICH MAY PARTIALLY EXPLAIN THE LACK OF STRENGTHENING THIS MORNING.) Something is wrong if we can’t look at all the data available (plane, satellite etc), analyze it in context, and make a judgment call!! This was a hurricane yesterday and it has been a hurricane all day today. If a storm this size was off the coast of Miami, would it be ok to wait until 7 hours before landfall to upgrade him to a hurricane because we were waiting for one piece of data? I am not a happy bunny about this!! <end rant alert>(end too many exclamation point alert too)

Ok so Ernesto, as you can see, is at 18.9N, 87.5W, heading W at 18mph onto the Yucatan peninsula. Central pressure is now 980mb, winds are 85mph. The forecast track takes him across the peninsula and back out into the Gulf by tomorrow afternoon. Sea surface temperatures are over 30 deg C, but the subsurface water temperature is only warmer than 26 deg C in the upper 50m of the water column… mostly because the bathymetry of the sea floor there is quite shallow so it can’t be much deeper anyway. The circulation is really quite good over the entire troposphere.

Meanwhile over in the eastern Atlantic is a new blob. May I introduce you to the most-likely future Tropical Storm Gordon?

(satellite image of the tropical Atlantic, Caribbean and Gulf).
This blob is centered around 12.2N, 33.5W, heading W at 10-15mph. It doesn’t have much convection yet, but the circulation is picking up in the lowest half of the troposphere. Looks like he will continue generally westward for the next couple of days, but may track north of Ernesto. So the Caribbean islands, Bahamas, Bermuda, and east coast of the US should keep an eye on this little rascal.

I shall conclude with a graphical depiction of what is really happening on Mars...

Until the morrow!

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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.


AmyMo said...

I'll be in St. John so Gordon needs to simmer down.

Jyotika said...

Hi! When will you be there? You might be ok with the Atlantic Blob, but I think there may be a blobette on the heels in about 1-1.5 weeks... Send me a time frame for when you are out there.

AmyMo said...

Leaving tomorrow for a week. Crossing fingers and toes. :)