Tropical storm warnings are flying for much of the Bahamas and a Tropical Storm Watch is out for much of the central Florida coast, as a steadily organizing Tropical Depression Nine grinds slowly northward through the Bahamas toward the Southeast U.S. coast.
As of 11 a.m. EDT Sunday, TD 9 was centered about 95 mi (155 km) west of the central Bahamas, heading north at 7 mph (11 km/h) with top sustained winds of 35 mph (55 km/h) and a central pressure of 1002 mb. Satellite imagery at midday Sunday showed TD 9 boasting a large shield of heavy thunderstorms (convection) that covered most of the Bahamas. This convection was increasing in intensity and areal coverage. Conditions were favorable for development, with moderate wind shear of 10-15 knots, warm ocean temperatures of 30 degrees Celsius (86°F), and a moist atmosphere.
Forecast for TD 9
Today marks the first time in a decade – since 2015 – that the United States has made it as late as September 28 without a single hurricane landfall. That streak appears likely to continue, based on the latest forecasts. TD 9 is now expected to miss making landfall in the Southeast U.S. and head eastward out to sea, following a path cleared out by big brother Hurricane Humberto (Fig. 2).
Favorable conditions for development for TD 9 are expected to continue through Tuesday, when NHC predicts that it will become a Category 1 hurricane with 75-80 mph winds. The next name on the Atlantic list is Imelda. Because of the storm’s more southerly formation location and slower than expected forward speed on Saturday and Sunday (Fig. 1), Hurricane Humberto is now expected to have more of a steering influence on TD 9’s track than earlier anticipated. Humberto will pull TD 9 sharply to the east-northeast well before it can make landfall in the Southeast U.S. This turn is predicted to occur on Tuesday, when TD 9 will be several hundred miles south of South Carolina. At that time, wind shear is expected to the rise to a high 20-30 knots, and TD 9 will be wrapping in dry air from the southwest into its core, slowing the intensification process. The long-term fate of TD 9 is of high uncertainty, but NHC is currently predicting that the storm will continue heading eastward out to sea and become extratropical by next weekend.
Humberto peaks as a Cat 5
On Saturday, Hurricane Humberto peaked as a Category 5 storm with 160 mph winds, becoming the second Cat 5 of the season in the Atlantic, along with Hurricane Erin. The year 2024 also had two Cat 5s — Beryl and Milton — and the two-year period 2024-2025 is only the second time that the Atlantic has seen two consecutive years with a Cat 5, the other being 1932-1933 (h/t to Jasper Deng for this stat).
Remarkably, all three of this year’s Atlantic hurricanes have been Category 4 or 5 storms — the first time since 1935 that the first three hurricanes of the season have attained major hurricane strength.
Humberto is the planet’s fourth Category 5 storm of 2025, joining Typhoon Ragasa in the Northwest Pacific (September 21), Hurricane Erin in the Atlantic (August 16) and Cyclone Errol off the coast of northwest Australia (April 16). The 1990-2024 average globally for an entire year is 5.3 Cat 5s; there were five in 2024.
Forecast for Humberto
As of 11 a.m. EDT Sunday, Humberto was a weaker but still formidable Category 4 storm with 150 mph (240 km/h) winds and a central pressure of 934 mb, headed west-northwest at 13 mph (20 km/h). As Humberto embarks on a classic recurvature path that’s predicted to take it several hundred miles west of Bermuda on Tuesday or early Wednesday, wind shear will be increasing and ocean temperatures cooling, causing steady weakening. Tropical storm watches could be required on Bermuda later today as Humberto approaches, with tropical storm conditions looking increasingly likely on the island for Tuesday night.
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Great Job Jeff Masters and Bob Henson & the Team @ Yale Climate Connections Source link for sharing this story.
