24 August 2016

Big Trouble Brewing For Southeast U.S.??

Posted by Dan Satterfield

GOES071520162373av3qsTropical Update :
I’m not going to post any specific model data since there is still quite a bit of disagreement, and any individual run this far out is worthless, but that said:
My concern that a tropical cyclone will threaten the SE U.S. in 5-7 days is growing rapidly. The system is looking much healthier on the satellite images tonight. Increased convection and shear seems less.
Lower wind shear is more conducive to a tropical cycle intensifying.

Lower wind shear is more conducive to a tropical cycle intensifying. Click for larger version.

The wind shear is forecasted to weaken greatly and it will move over an area of high tropical cyclone potential water (Based on the depth of the 26C isotherm). My gut feeling is that we have big trouble coming. If you’re living in or near South Florida, to Southern Louisiana (Yeah, I know), you need to start thinking about what and where you would go if evacuations are needed. Pay daily attention to a trusted weather source. If you see someone posting model forecasts of where a giant hurricane will be in 5-8 days, that is NOT a trusted weather source.

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Some folks I personally know that are superb Meteorologists in the region, and you will get facts and no hype from these people:
Miami folks- John Morales is your guy to listen to. New Orleans: David Bernard. Orlando: WESH Metr. Amy Sweezey. Baton Rouge: Rob Perillo. Tampa: Steve Jerve. Mobile: Alan Seals. I see all of these folks frequently at science conferences. They are highly knowledgeable, and care about giving accurate info. (If I left someone out my apologies- email me!)
 
The models are in decent agreement on track, but there are major differences on strength.

The models are in decent agreement on track, but there are major differences on strength.

Images (on right) show the lower shear region Invest 99L is moving into, and a spaghetti plot showing high confidence in the track over the next 96 hours, with divergence afterwards. Some of these tracks are much less reliable than others. I show it only to give you an idea of the general threat area, IF it develops into TS Hermine.

I will say that the Euro model is rather alarming, and for the 3rd run in a row. You will not see this online, because the data is protected by crown copyright, and you have to pay for it. I can see it, but cannot show you most of that data, and it’s likely wrong anyhow this far out.
I sure hope so. I really hope so…
How warm the water is, is an important factor but more important is the depth of that warm water. This is called the TCHP- tropical cyclone heat potential.

How warm the water is, is an important factor but more important is the depth of that warm water. This is called the TCHP- tropical cyclone heat potential.

NOAA TPC Discussion below:
Satellite images, surface observations, and radar data from the
Lesser Antilles indicate that a broad area of low pressure
associated with a tropical wave is located near Guadeloupe.
Although environmental conditions are only marginally conducive for
development, this system could become a tropical depression during
the next day or two while it moves west-northwest at 15 to 20 mph
across the Leeward Islands and the Greater Antilles. Conditions
could become more conducive later this week while the system moves
near the southeastern and central Bahamas. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate this
disturbance later today, if necessary. Interests from the islands
of the northeastern Caribbean Sea to the Bahamas should continue to
monitor the progress of this system. Gusty winds, heavy rains, and
possible flash floods and mudslides could occur over portions of
these areas regardless of tropical cyclone formation. Please consult
products issued by your local meteorological offices for further
details.
* Formation chance through 48 hours…medium…50 percent
* Formation chance through 5 days…high…70 percent