WOKV

Talking the Tropics With Mike: Eye on possible long term development

By Mike Buresh,

2 days ago

The “Buresh Bottom Line”: Always be prepared! ..... First Alert Hurricane Preparation Guide ... City of Jacksonville Preparedness Guide ... Georgia Hurricane Guide .

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*** LOCAL (Jacksonville/NE Fl./SE Ga.) IMPACTS FROM THE TROPICS: None

The Atlantic Basin Overview:

The Atlantic Basin has been quiet since Beryl early this month. It’s about to wake up.....

(1) The European model continues to lead the charge on tropical development over or near the W. Atlantic (takes a hurricane east of Florida in recent model runs) ... the GFS model (ranging from a hurricane in the Gulf of Mexico to a weak westward moving tropical wave) & Canadian model (takes a hurricane somewhere over the Gulf of Mexico) are somewhat in the “game” but wildly inconsistent. Timing is anywhere from this weekend to early next week.

The potential development seems to be tied to a tropical wave now moving entering the Central Atlantic which will move westward through an expansive - though thinning - plume of Saharan dust & relatively dry air. Once out of the dust “cloud” & in an overall environment that appears more favorable - about next Thu./Fri. (Aug. 1/2) - & near the NE Caribbean or SW Atlantic, models then do their “thing” & in some way, shape or form develop a tropical cyclone. Model solutions are jumping all over the place which is no surprise given the long range not to mention there still isn’t even an actual surface feature. But this will be something to keep a close eye on for the Caribbean, Gulf & Western Atlantic. It is way too early to have any idea where at all how this scenario might - or might not - pan out. Long term movement will largely be dictated by the sprawling Bermuda High & a persistent secondary upper level high (the infamous “heat dome”) that’s been camping out across the Central or Southern U.S. much of this summer.

In a general sense... potential development would generally fit the pattern with sprawling high pressure spread out at northern latitudes + a MJO impulse beginning to push eastward from the Pacific.

(2) Low pressure is developing east of New York City over the NW Atlantic. This low could be a hybrid type storm system (subtropical) bringing heavy rain, gusty winds & rough seas/surf to Boston & nearby areas of New England Mon.-Tue.

The velocity potential anomalies map below shows a lot of sinking air (brown lines) - & a lack of convection - over the Atlantic Basin to the far East Pacific while rising air (green lines) is over the Central & West Pacific more convection is notable. Often the green areas (MJO pulse) will correlate with increased tropical activity. So it’s the W. Pacific that will be more active now but this pulse should move eastward - signs of which we’re already seeing - by the end of the month & especially into the first two weeks of August helping to set off a return to a more active Atlantic.

REMEMBER WHEN A TROPICAL STORM OR HURRICANE IS APPROACHING: Taping windows is *not* recommended & will not keep glass from breaking. Instead close curtains & blinds.

Realize the forecast cone (”cone of uncertainty”) is the average forecast error over a given time - out to 5 days - & *does not* indicate the width of the storm &/or where damage might occur.

The upper oceanic heat content (UOHC) [tropical cyclone heat potential/TCHP] across the SW Atlantic, Gulf & Caribbean is unseasonably high for this time of year:

Water vapor loop (dark blue/yellow is dry mid & upper level air):

July tropical cyclone origins (early season breeding grounds are the Gulf &/or Western Caribbean:

Averages below based on climatology for the Atlantic Basin for July (1 hurricane so far, 3 tropical storms):

Wind shear (red - strong shear; green - low shear):

Saharan dust spreads west each year from Africa driven by the prevailing winds (from east to west over the Atlantic). Dry air = yellow/orange/red/pink. Widespread dust is indicative of dry air that *can* interfere with the development of tropical cyclones. However, sometimes “wanna’ be” waves will just wait until they get to the other side of - or away from - the dust plume then try to develop if other conditions are favorable. In my personal opinion, there is way too much “hoopla” about the presence of Saharan dust & how it relates to tropical cyclones. In any case, the peak of Saharan dust typically is in June & July.

2024 names..... “Debby” is the next name on the Atlantic list (names are picked at random by the World Meteorological Organization... repeat every 6 years). Historic storms are retired [Florence & Michael in ’18 (the last time this year’s list was used)... Dorian in ’19 & Laura, Eta & Iota in ‘20, Ida in ‘21 & Fiona & Ian in ‘22]). In fact, this year’s list of names is rather infamous because of the ‘04 season when Charley, Frances, Jeanne & Ivan - all retired names - hit Florida within a matter of about 6 weeks. The WMO decided - beginning in 2021 - that the Greek alphabet will be no longer used & instead there will be a supplemental list of names if the first list is exhausted (has only happened three times - 2005, 2020 & 2021). The naming of tropical cyclones began on a consistent basis in 1953. More on the history of naming tropical cyclones * here *.

East Atlantic:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content over the Gulf, Caribbean & deep tropical Atlantic. The colors will brighten greatly as the water warms to greater depths deeper into the season: