• Talking the Tropics With Mike: Weak low pressure over North Florida

    By: Michael Buresh

    Updated:

    Aug. 17, 2019 - The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.  

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    There are some signs that the Atlantic is becoming a little more active.  

    The velocity potential anomaly map below shows rising vertical velocities (green lines) overspreading the Pacific Basin.  This should help with some tropical development in the short term over the Eastern Pacific & eventually - by late Aug. - over parts of the Atlantic Basin.  And could help get something going next week over the Western Gulf.

    Weak low pressure - mostly at mid & upper levels - has formed near & west of Jacksonville, FL.  The upper level "energy" is forecast by models to split with some moving northeast quickly over the Western Atlantic & becoming absorbed by an upper trough while another piece initially drifts westward before turning more east/northeast by midweek.  Little true surface development is likely.  Therefore, I'm forecasting few impacts outside of a continuation of heavy rain thanks to tropical moisture, some extra lift/energy from the upper air dynamics & slow storm/cell motion.  Rather remarkably, the NHC has highighted this highly disorganized system for a very low probability of development.

    An examination of dust over the Central & Eastern Atlantic shows a continuation of a good deal of dust over the Central & Eastern Atlantic.  While such dry air can inhibit tropical development initially, once any waves are farther west or if the wave can stay a little south & out of the dust "cloud" - & IF all other conditions are equal - organization/strengthening can occur.  The 2005 hurricane season stands out (along with several other seasons) as a "dusty" Eastern Atlantic but disturbances simply waited to get out of the dust - further to the west - to develop & then "make history".

    2019 names..... "Chantal" is next on the Atlantic list (names are picked at random... repeat every 6 years... historic storms are retired (Florence & Michael last year):

     

    It was 15 years ago - 2004 - that the Atlantic Basin suddenly came awake in what had been a quiet season so far.  An El Nino abruptly collapsed midseason.... the first named storm occurred near the Carolina coast early in Aug. followed by tropical storm Bonnie that hit the Panhandle on Aug. 12 dropping an EF-2 tornado on Jacksonville's NW side followed the next day by powerful Cat. 4 Charley in SW Fl. at Port Charlotte. Frances, Jeanne & Ivan followed from late Aug. through mid September - all hurricanes that hit Fl. with Frances & Jeanne having profound effects on Jacksonville/NE Fl. & SE Ga. while Ivan devastated Pensacola taking out parts of the I-10 bridge.  Many in Florida will never forget the '04 season!

    There was a lasting impact on Fl. would be an understatement.  Consider:

    (1) hurricane days (like snow days up north) were added to school district calendars & remain a fixture for all school districts to this day.

    (2) the hurricane deductible was born & is maintained by most Fl. insurance companies to this day. The implication: if a named storm does damage to one's property, a hurricane deductible has to be paid (usually far higher than the standard deductible) before insurance kicks in & pays.

    (3) the '04 season was the first time since hurricane Andrew that upgraded building codes were tested.  The results were very positive. 

    Atlantic Basin today:

    East Atlantic:

    p>Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear of which there is plenty across the Atlantic at the moment:

     

    The Atlantic Basin:

    Water vapor imagery (dark blue indicates dry air):

    Deep oceanic heat content:

    Sea surface temp. anomalies show some "cool" water remaining over the E. & N. Atlantic but avg. to above avg. temps. for much of the rest of the Atlantic Basin.....

    SE U.S. surface map:

    Surface analysis centered on the tropical Atlantic:

    Surface analysis of the Gulf:

    Caribbean:

     

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