Talking the Tropics With Mike:Florence crawling through South Carolina well north of Jacksonville FL

Historic rains for the Carolina's

Sept 15, 2018 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.  

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FLORENCE - landfall - as Cat. 1 - early Fri.... edge of eyewall at 6am... center of the eye at 7:15am EDT at Wrightsville Beach, NC very near Wilmington..... moving ever so slowly southwest


* NONE (rip currents at area beaches)

Everyone up & down the east coast of the U.S. - particularly the Carolina's - needs to stay vigilant regarding the latest forecasts...

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NO tropical storm - & certainly hurricane - force winds or wind gusts will occur in association with Florence through the weekend (or ever!):

"Florence"  - a named storm for the 14th straight day Fri. - became the 3rd hurricane, 1st "major" of the '18 Atlantic season Tue.... went Cat. 3 then briefly Cat. 4 last Wed. ...  fell apart in the face of shear & dry air Thu.... continues moving into the Western Atlantic & made the expected comeback reaching Cat. 4 strength again Mon.  The tropical cyclone made the important turn northwest reaching Jacksonville's latitude BUT hundreds (400+) of miles to the east - late Wed./Wed. night.  Florence went through some serious structural alterations Wed. probably due to nearby dry air & some shear which has caused weakening & never could fully recover. Florence made landfall early Friday as a Cat. 1 & the underside (south portion) of the circulation is pretty quickly weakening while the north & east quadrants remain relatively strong.  Such an evolution is not uncommon with landfalling tropical cyclones as dry air is often first ingested from the west due to the counter-clockwise circulation.

Despite the general weakening the last couple days, Florence has been - & will be - a big hit on the Carolina's:  Major to severe impacts can be expected. Don't make the mistake of getting too caught up in individual run output of any particular model.... OR in what unreliable sources might be posting.... OR tracking just the center!  Dangerous conditions will extend far from the eye of Florence.  And do NOT underestimate the power of Florence even though the storm has weakened.  Very heavy rain will cause widespread flooding, & the storm surge will likely be greater than what might usually be expected with a lower category storm.

As for track, the "dip" south/southwest is occurring & will continue through Sat. night then straightening back to the west before curving rather sharply north then northeast & accelerating early next week as Florence gets caught up in the westerlies. Now that the tropical cyclone is inland, Florence has lost the majority of its energy source - the warm ocean water - & will rather quickly fill & weaken but still capable of dumping very heavy rain. It's worth noting that the decay will be slower than usual since the center will hug the coast for a while allowing a good portion of the circulation to remain over water.

As Florence flounders over the Carolina's there will be a pounding at the beaches with wave action & tremendous amounts of rain - most significant of these impacts will be north & northeast of the center.

It looks like direct impacts on the U.S. will continue through Tue., the 18th or so in one form or another. Flooding may very well follow the path of the post-tropical low pressure from Eastern Tennessee northeastward through parts of Virginia, Pennsylvania, Maryland, New York & Massachusetts later in the weekend into early next week!

Bottom line: Don't panic but always be prepared.....



The map below is a mirror of the above spaghetti plots but shows an ensemble of all the model runs. DEFINITION OF ENSEMBLE MODELING: A set of forecasts that present the range of future weather possibilities. Multiple simulations are run, each with a slight variation of its initial conditions and with slightly perturbed weather models. These variations represent the inevitable uncertainty in the initial conditions and approximations in the models. They produce a range of possible weather conditions.

40 foot waves have been measure offshore of N. Carolina!:

Wave height model (GFS) forecast... gradual improvement as Florence weakens:

Heavy rain by late week middle east coast.  Rainfall over parts of N. Carolina & Virginia may exceed 1-2 feet! 1-3 day rainfall:

4-6 day rainfall:

Tropical cyclone record rainfall (for a single storm) may be broken in some states:

Wide view of the busy Atlantic Basin.  Joyce developed over the N. Atlantic Wed.... in addition to Isaac - which has since dissipated over the Caribbean... & Helene.  Another wave is moving off Africa & will move westward.  Forecast models are also showing possible long range development near & south of Bermuda & northeast of the Bahamas.... as well as over the E. Atlantic later next week.... & a wave with very heavy rain has moved into Texas running out of warm water before it could develop further.

Isaac has officially degenerated into an open wave (trough) over the Caribbean.  IF Isaac can somehow survive its current hostile environment, somewhat more favorable conditions will be over the W. Caribbean & Gulf of Mexico next week.

Helene & its full recurvature will continue over the Central/ E. Atlantic.  Helene might interact with Joyce over the N. Atlantic.  Both, however, stay far to the east over the open Atlantic.

E. Atlantic:




Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear.  Note weaker shear in the path of Florence over the W. Atlantic while there's much stronger shear over the Caribbean......

The Atlantic Basin....



Gulf of Mexico:


Water vapor imagery (dark blue indicates dry air) - notice the dry air right up against Florence:

Deep oceanic heat content is seasonably high over the Caribbean, Gulf of Mexico & SW Atlantic as one would expect now that we're near the peak of the hurricane season....

Sea surface temp. anomalies show a general recent warming over a good portion of the Atlantic Basin including rather dramatic warming east of the Caribbean & near the NE coast of S. America ....

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:


The Central Pacific: