Potential tropical development in Gulf poses primary US threat before end of September
Tropical development in the Gulf of Mexico poses the greatest short-term risk to the United States this September, with record-warm waters fueling potential rapid intensification and limited prep time for coastal areas.
In today’s Forecast Feed, AccuWeather’s Bernie Rayno takes a look at the latest in the tropics.
Very warm waters, steering currents and other factors point to the Gulf as the main area of concern for tropical development over the next couple of weeks, AccuWeather meteorologists say. Other systems may form farther east over the Atlantic basin, but Gulf development would allow the least time for U.S. coastal preparations.
"The western Caribbean and Gulf will be monitored closely starting around Sept. 18, continuing through at least the end of September," AccuWeather Lead Hurricane Expert Alex DaSilva said.
"A storm may develop in that zone and move toward the United States. Due to the formation so close to land, storms that develop in this area would leave coastal residents with the least preparation time," DaSilva said.
On average, based on typical steering currents, a tropical storm that forms in the northwestern Caribbean may have only three to five days before it potentially reaches the U.S. However, a storm that forms in the Gulf could reach the U.S. coastline in as little as two days.
"Any storm that moves into the Gulf has the potential to rapidly intensify due to the record-high ocean heat content," DaSilva said. Ocean heat content accounts for not only sea-surface temperatures but also the warmth extending into deeper waters.
Gulf heat content is likely to remain extremely warm through the rest of September. Water temperatures in parts of the western Caribbean and the Gulf are near 90 F, well above the 80 F threshold for tropical development.
"In general, tropical activity is expected to increase during the second half of September," DaSilva said.
There is a high risk of tropical development potential starting Tuesday, as a tropical wave pushes off Africa and moves into the main development region of the Atlantic. A second tropical wave is expected to move off the coast of Africa this week. Both tropical waves will be monitored closely for any signs of development.
“There should be less disruptive wind shear, dry air and Saharan dust in the main development region of the Atlantic this week, right where we suspect that some activity may occur," DaSilva said. "The atmospheric conditions that limited tropical development in recent weeks are easing. Every tropical wave moving off Africa will be monitored closely, as they move through warm waters with conditions that are conducive for tropical development.”
Because of the extended lull in tropical activity, which began in late August, AccuWeather has slightly lowered its projections of tropical storms and hurricanes for the 2025 Atlantic season. However, the tropical forecast team of experts at AccuWeather continues to project that two to four additional major hurricanes may still develop during the remainder of the season, which concludes on Nov. 30.
Thus far, Erin has been the only hurricane and the only major hurricane to occur this season. Erin reached Category 5 intensity on the Saffir-Simpson Hurricane Wind Scale, with sustained winds of 160 mph. A major hurricane has Category 3 strength with winds of 111 mph or greater.
Want next-level safety, ad-free? Unlock advanced, hyperlocal severe weather alerts when you subscribe to Premium+ on the AccuWeather app. AccuWeather Alerts™ are prompted by our expert meteorologists who monitor and analyze dangerous weather risks 24/7 to keep you and your family safer.
Report a Typo
