First Alert Weather

Talking the Tropics w/Mike: Heads-up-disturbance to move east of Florida & near Bahamas by Sun./Mon.

Talking the Tropics with Mike Buresh

Jacksonville, Fl. — THE TROPICS:

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Tropics threats/impacts for Jacksonville/NE Florida/SE Georgia: None through Saturday but an increasing risk for rip currents & rough seas & surf by late Sunday into parts of next week. Gusty winds are possible too - any & all impacts dependent on possible development of a tropical wave near Puerto Rico - + the system’s (may be “Imelda”) 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. - primarily ‘94-L’. Recent indications & model output indicate the two systems - ‘94-L’ & Humberto - will mostly remain separate outside of perhaps some impacts due to outflow from either or both systems. 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 before this complicated steering pattern becomes well established & more predictable. NOAA & the N.W.S. are 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.

The 500mb (approx 30,000 feet) European forecast for Monday, Sept. 29:

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

(1) ‘94-L’ is near Puerto Rico & looks to be the potentially bigger “trouble maker” for the U.S. This wave will move northwest & has the *potential* for U.S. impacts as early as Sunday night/Monday. There is a good deal of wind shear - 30-40+ mph - largely thanks to an upper level low near & east of the Bahamas + interaction with the mountainous terrain of Hispaniola. But as the wave progresses northwest, the shear should relax over the weekend & will be over very warm ocean water. 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 Georgia & 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 near or just off the east coast but very near the warm Gulf Stream. Recently long range global forecast models are indicating a system separate from Humberto with a track northwest into the Southeast U.S. anywhere from Mon. to Tue. There may not be much time to prepare once this disturbance shows its hand & it can be determined when & where there might be landfall.

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. A hurricane hit somewhere on the Southeast U.S. coast is *possible*.

(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 - competing outflow in particular - with 94-L to the west though it appears there may be just enough separation to keep the two systems as their own entities. Humberto may slow or even stall for a while next week over the Central &/or Western Atlantic.

N.W.S. Puerto Rico radar:

Also of interest in trying to forecast ‘94-L’ is a possible typhoon teleconnection. “Bualoi” will move west/northwest then turn more northwest while moving into Vietnam over the next few days. This movement is due to a pretty strong upper level trough well to the west over China edging southward to the west of Vietnam. I’m thinking that perhaps the forecast models - especially earlier this week - were too far east with the U.S. trough given what’s going on over the W. Pacific. Similarly - also underplaying the strength & positioning of the Bermuda High over the Eastern Atlantic. Recently, we have seen the forecast models shift west with ‘94-L’ perhaps due to the upper level trough being more to the west vs. earlier forecasts. This would have major implications on where 94-L would go.

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. of this week.

Gabrielle is now caught up in the prevailing westerlies & is accelerating east/northeast & will move across the islands of the Azores Thursday through early Friday. 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).

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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:

East & Central Pacific:

“Narda”:

Central Pacific:

Hawaii satellite imagery:

West Pacific:

Global tropical activity:

“Bualoi” will move through the middle of the Philippines:

“Ragasa” did thread the needle between the Philippines & Taiwan & is moving into China:

“Neoguri” is crawling & is expected to stay east of Japan:

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