• Talking the Tropics With Mike: Tropical waves continue over the Atlantic

    By: Michael Buresh

    Updated:

    Aug. 1, 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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    After 1 named storm in July - "Barry" (marginal hurricane at most), we head into the busier part of the Atlantic hurricane season.  The third named storm is usually "on the map" by Aug. 13... the 4th by Aug. 23 & the 5th by Aug. 31 (43 years of data).  In other words, we're about right on schedule so far.

    ATLANTIC BASIN:

    A tropical wave that poured on Puerto Rico is now near the Fl. Straits & Bahamas.  There remains little organization with strong shear (30+ mph) out of the west & southwest tearing away at the wave though are occasional bursts of convection (t'storms).  Yes - the system will move near Florida through the weekend, but the shear + some land interaction should continue to keep the system from organizing.  There remains some potential for organization upon a turn to the northeast by late in the weekend/early next week but by then the disturbance will be moving away from the U.S., & it becomes a moot point.  BOTTOM LINE: a weak tropical wave (we see this during EVERY hurricane season!) will be in the vicinity of Fl. through Sunday.  Any local / Florida impacts would be an even greater increase in heavy rain in what is a typically wet time of year.

    An active wave - '96-L' - has come off the coast of Africa over the E. Atlantic.  Little short term development is expected but something to keep an eye on in the longer run.  Between the 5th & 10th of August, the wave should be approaching the Caribbean &/or SW Atlantic with potentially more favorable conditions to organize.  This wave should be fairly close to the Bahamas - & east of Fl. - approximately Aug. 7 - 9th.  Still early, but I would not be surprised if this waves becomes "Chantal".  And again emphasizing how early it is in trying to forecast a wave that's not even developed yet into a tropical cyclone. Key in the future long term movement will be a recently persistent upper level trough over the Eastern U.S. + the exact positioning of the Bermuda High.  It should be noted that a weaker, more shallow system will likely have the potential to get farther west which then become more probelmatic if intensification then follows.  Forecast models have been inconsistent - to say the least - on the development of this wave but it needs to be carefully monitored.

    Model plots for wave '96-L':

    Radar imagery courtesy S. Fl. Water Management District:

    The GFS surface model output below emphasizes my motto: "they're just forecast models!".... in addition to why we need to be vigilant each day (things change!).  The first image is the 00Z (8pm) model from Aug. 1 & shows a powerful hurricane just off the coast of Fl. on Sun., Aug. 11.  6 hours laters, the same model for the same forecast time shows virtually nothing(!).

     

     

    The chart below is the upper (500mb) level forecast for next Wed., Aug. 7th.  The weak - but still significant & recently persistent - trough over the Eastern U.S. is what will help guide the weak Puerto Rican wave north then northeast to the east of Fl. through early next week & MAY also play an important role in the eventual track of the Eastern Atlantic wave.

    An examination of dust over the Central & Eastern Atlantic shows a pretty heavy area of dust/dry air over the Eastern Atlantic - typical for this time of year.  While such dry air can inhibit tropical development initially, once the wave is farther west & out of the dust "cloud" - IF all other conditions are equal - organization/strengthening can occur.  The 2005 hurricane season stands out as a "dusty" Eastern Atlantic but disturbances simply waited to get out of the dust - further to the west - to develop.

    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):

     

    East Atlantic:

    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. 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:

     

    The East & now Central Pacific is again active.  "Erick" will be south of Hawaii by late week & likely quickly weakening after being at hurricane strength over the next few days.  Some rough surf will result on the south-facing beaches.  "Flossie" follows & could be near/north of Hawaii early next week but - again - as a much weaker system.

    Flossie model plots:

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