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

Jacksonville, Fl. — THE TROPICS:

***** ALWAYS CHECK & RE-CHECK THE LATEST FORECAST & UPDATES! ****

Tropics threats/impacts for Jacksonville/NE Florida/SE Georgia: None through Friday but an increasing risk for rip currents & rough seas & surf by late Sunday into parts of next week. Gusty winds are possible too - all dependent on possible development of a tropical wave near Puerto Rico - + the system’s location & intensity relative to the local coast.

The Atlantic Basin Overview:

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

Two active tropical waves deserve a lot of attention & *may* eventually (next week sometime) have at least some impacts on the U.S. These two waves are in relatively close proximity & may interact with one another by early next week. In fact, the global forecast models seem to sometimes merge the two waves while in other model runs they just entirely lose one of the systems... & still in other model runs maintain two distinct systems. The GFS model seems to be particularly inconsistent & has had a tendency to merge 94-L with Humberto to the east. Most other global forecast models keep the two systems separate with 93-L uncomfortably close to the Bahamas early next week. How exactly these systems move - especially 94-L - will be largely modulated by an upper level trough over the Eastern U.S. This trough could either sling-shot 94-L to the west & into the U.S. east coast from Ga. to the Carolina’s or swing the disturbance more out to the east. It will be a while yet - perhaps 3+ days - before this complicated steering pattern becomes well established & more predictable. NOAA & the N.W.S. is trying to help out the forecast models by launching extra weather balloons from Florida to the Mid-Atlantic into the weekend (including Jacksonville N.W.S.) as well as special hurricane recon missions to sample the weather environment over & near the Caribbean & Southwest Atlantic.

Folks from the Caribbean to the Bahamas to the U.S. east coast to eventually Bermuda should stay up to date on the latest forecasts.

(1) ‘94-L’ is near Puerto Rico. This wave will move northwest & has the *potential* for U.S. impacts next week. There is a good deal of wind shear - 30-40+ mph - largely thanks to an upper level low near & east of the Bahamas. But as the wave progresses northwest, the shear should relax over the weekend. The system is *currently* projected to move east of Florida early next week but this could be a very close call. Then the system should move north/northwest & may impact the eastern seaboard from the Carolina’s to the Mid-Atlantic by the middle of next week. The exact track will be dictated by the upper level trough moving into the Eastern U.S. over the weekend/early next week with a potential closed/cut-off low that may capture this wave drawing it counter-clockwise west/northwest. It’s even possible the upper trough will not fully capture the potential tropical cyclone leaving it to swirl just off the east coast but very near the warm Gulf Stream. Some global models - the European included - shows ‘94-L’ moving east for a while before turning back to the west. This is an exceedingly difficult forecast right now & there will have to be updates in the days ahead. At the very least it does look like rough seas & surf for NE Fl. & SE Ga. with a high rip current risk which may spread up the eastern seaboard as far north as Virginia.

(2) ‘93-L’ was upgraded to “Humberto” Wed. afternoon. It looks like this wave follows in the wake of Gabrielle but a little more west which could mean a direct threat to Bermuda next week. Conditions look quite favorable for this wave to become a hurricane - possible Cat. 3+ over the next few days into next week, but it should stay well east of the U.S. There is some chance for some interaction with 94-L to the west though it appears there may be just enough separation to keep the two systems as their own entities.

N.W.S. Puerto Rico radar:

Tropical wave ‘92-L’ was upgraded to tropical depression #7 early last Wed. over the Central Atlantic & was then upgraded to tropical storm Gabrielle later Wed. morning & intensified into a hurricane Sunday afternoon peaking at Cat. 4 intensity Monday through early Tue.

Gabrielle is now caught up in the prevailing westerlies & is accelerating east/northeast & will move near or across the islands of the Azores Thursday. Increasing shear + cooler ocean temps. will combine to cause fairly fast weakening *but* Gabrielle is still forecast to be near hurricane while impacting the Azores.

‘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):

September Atlantic tropical cyclone origins:

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

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..... “Imelda” 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. The colors will brighten greatly as the water warms to greater depths deeper into the season. It’s worth noting that the deep oceanic heat content right now is not as high as this time last year.

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: