Talking the Tropics With Mike: Last day of the Atlantic hurricane season!

Jacksonville, Fl. — THE TROPICS:

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Tropics threats/impacts for Jacksonville/NE Florida/SE Georgia: Non-tropical or subtropical low pressure developing & strengthening east of Florida will northward over the far Western Atlantic & will help cause another round of strong onshore flow, gusty winds, flooding at times of high tide & some rain through Friday into Saturday.

The Atlantic Basin Overview:

The Atlantic hurricane season is June 1st through Nov. 30th.

(1) A Tropical Storm WARNING: St. Barthelemy and St. Martin... Sint Maarten.

Tropical wave ’95-L’ was upgraded to tropical storm “Jerry” Tue. morning while steadily & swiftly moving west/northwest. Jerry has been struggling against moderate to strong west/northwest shear while veering more northward with time thanks to a rather far to the east positioning of the Bermuda High + a strong upper level trough headed for the Eastern U.S./far West Atlantic. A sharper turn to the north then northeast will keep Jerry well south & east of Bermuda while achieving full re-curvature. Despite the disheveled state - resembles more of a surface trough of low pressure - due to the persistent shear, Jerry has a window to strengthen through Sunday once north of the Caribbean Islands & before the sharp turn toward the northeast then east over the Central Atlantic. Heavy rain for some of the Northern Caribbean Islands will subside by Saturday.

(2) Low pressure is forecast to develop near the U.S. east coast east of Florida by Friday & should move north/northeast while deepening then may bend back to the northwest for a while bringing the low closer to the coast - & possibly just onshore - of Virginia & Maryland, possibly as far north as New York City. Given the proximity to the Gulf Stream + excellent upper level divergence (a chimney effect helping upper level ventilation) thanks to an approaching strong upper level trough, there is some chance this low may try to take on some subtropical characteristics while moving from near the Carolina’s to the Mid-Atlantic through the weekend. A hybrid low or not - heavy rain, rough surf, large waves & gusty winds are likely to impact the Carolina’s to at least Chesapeake Bay through the weekend.

South Florida Water Management District radar imagery:

7-Day rainfall forecast:

(3) Subtropical storm “Karen” was upgraded Thursday evening over the far Northeast Atlantic north of the Azore Islands & won’t last long nor impact any land areas while moving to the northeast.

‘Velocity potential anomalies’ below. shows “Rising” air (green lines) equates with an uptick in overall convection. With rising air, conditions are generally more favorable for tropical development. Where there are brown lines, the air is generally sinking & is often less conducive to tropical cyclones (though not impossible to have development).

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

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Federal Alliance for Safe Homes (FLASH) * here *.

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 6 days - & *does not* indicate the width of the storm &/or where damage might occur.

The map below shows the *average* time for a tropical wave coming off Africa to travel west & northwest. Only about 1 in 5 tropical waves - on average - become a tropical cyclone of some sort (depression/storm/hurricane):

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

October Atlantic tropical cyclone origins:

Averages below based on climatology for the Atlantic Basin for October:

Wind shear (red - strong shear; green - low shear). Shear is typically strong to start the hurricane season:

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 (we saw this with Beryl & Debby last year). It’s my personal opinion that 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, & we are indeed seeing a large “blobs” of Saharan dust over the Central & Eastern Atlantic that’s thinning with westward extent but enough of it to make for hazy skies across the Caribbean & - at times - across parts of Florida.

2025 names..... “Lorenzo” 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... Dorian in ’19 (the last time this year’s list was used) ... Laura, Eta & Iota in ‘20 ... Ida in ‘21 ... Fiona & Ian in ‘22... no names were retired in ‘23 for the first time since 2014... & Beryl, Helene & Milton last year in 2024]). 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 *.

Hurricane season climatology:

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 & tropical Atlantic. Brighter colors = warmer temps.:

Sea surface temps.:

Sea surface temp. anomalies:

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:

Caribbean:

Atlantic Basin wave period forecast for 24, 48, 72 & 96 hours respectively:

This past spring I visited the west coast of Florida - from Cedar Key to Tampa Bay - to see how the area is recovering from the very rough ‘24 hurricane season namely Helene & Milton:

East & Central Pacific:

“Priscilla” stays west of Mexico & the Baja but will bring some fringe impacts - gusty winds & heavy rain - to the Southern Baja of California. And some tropical moisture will push into the SW U.S. by late week/this weekend enhancing rainfall & potential flooding from Southern California to especially Arizona & New Mexico: