The Atlantic basin is very active today, with Hurricane Franklin becoming the first major hurricane of the season early this morning and Tropical Storm Idalia nearing hurricane strength near the western tip of Cuba.

As of 5:00 p.m. EDT, Hurricane Franklin was centered near 28.5°N 71.0°W, and was moving northward at about 9 mph. Maximum sustained winds were 125 knots (145 mph), with an estimated minimum pressure of 937 mb. This makes Franklin a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Franklin is the first major hurricane of the 2023 Atlantic hurricane season, and the strongest hurricane of the season so far. Fortunately, Franklin does not appear likely to threaten land areas, aside from some possible impacts in Bermuda from the outer bands of the hurricane. During the next 12 hours or so, some additional intensification is possible, as Franklin will remain over sea surface temperatures warmer than 29°C (84.2°F) in a low-shear environment. Sea surface temperatures are expected to start decreasing tomorrow, and wind shear is expected to increase by the middle of the week. Therefore, Franklin is likely going to begin weakening by tomorrow evening as it turns more to the northeast. Franklin is likely to accelerate to the northeast late this week and become a strong extratropical cyclone by Friday, though it should be noted that the ECMWF model shows Franklin turning east at a lower latitude and maintaining tropical characteristics for longer. A Tropical Storm Watch is currently in effect for Bermuda for Franklin. An Air Force Hurricane Hunter aircraft is en route to Franklin to investigate the hurricane later this evening.

Tropical Storm Idalia is gradually strengthening over the northwestern Caribbean Sea, and is close to hurricane strength as it poses a major threat to northwestern Florida on Wednesday. As of 5:00 p.m. EDT, Tropical Storm Idalia was centered near 21.4°N 85.1°W, and was moving northward at about 8 mph. Maximum sustained winds were 60 knots (70 mph), with an estimated minimum pressure of 987 mb. Idalia is close to hurricane intensity, and is likely to become a hurricane tonight near the western tip of Cuba. A NOAA Hurricane Hunter aircraft is currently en route to Idalia. With sea surface temperatures warmer than 30°C (86°F), a diffluent shear environment, and Idalia entering the Gulf of Mexico stronger than expected, steady or perhaps rapid intensification appears likely as Idalia moves northward into the Gulf of Mexico. Late tomorrow, Idalia is expected to turn more to the north-northeast as it strengthens, approaching the Big Bend region of Florida by early Wednesday morning. Idalia is likely to make landfall in northwestern Florida as a major hurricane, and is likely to bring hurricane conditions to much of the western Florida coast. Interests in the western Florida Peninsula and the Panhandle should have their hurricane plan ready and prepare to evacuate if ordered. After making landfall in Florida, it appears that Idalia will pass close to the United States east coast, and will likely re-emerge into the Atlantic in 4-5 days as a weakening tropical storm.

A Hurricane Warning is currently in effect for the Cuban province of Pinar del Rio, as well as the middle of Longboat Key, Florida northward to Indian Pass, including Tampa Bay. A Storm Surge Warning is currently in effect from Englewood, Florida northward to Indian Pass, including Tampa Bay. A Tropical Storm Warning is currently in effect for the Yucatan Peninsula from Tulum to Rio Lagartos, including Cozumel, Isle of Youth Cuba, Dry Tortugas Florida, Chokoloskee northward to the Middle of Longboat Key, and west of Indian Pass to Mexico Beach. A Storm Surge Watch is in effect for Chokoloskee northward to Englewood, including Charlotte Harbour, the mouth of the St. Mary’s River to South Santee River, South Carolina, a Hurricane Watch is currently in effect from Englewood to the Middle of Longboat Key, and a Tropical Storm Watch is currently in effect for the Lower Florida Keys west of the west end of the Seven Mile Bridge, and Sebastian Inlet Florida northward to South Santee River, South Carolina.

National Hurricane Center is expecting the following storm surge:

Aucilla River, FL to Chassahowitzka, FL…8-12 ft

Chassahowitzka, FL to Anclote River, FL…6-9 ft

Ochlockonee River, FL to Aucilla River, FL…5-8 ft

Anclote River, FL to Middle of Longboat Key, FL…4-7 ft

Tampa Bay…4-7 ft

Middle of Longboat Key, FL to Englewood, FL…3-5 ft

Englewood, FL to Chokoloskee, FL…2-4 ft

Charlotte Harbor…2-4 ft

Indian Pass, FL to Ochlockonee River, FL…3-5 ft

Mouth of the St. Mary’s River to South Santee, SC…2-4 ft Chokoloskee, FL to East Cape Sable, FL…1-3 ft Flagler/Volusia County Line, FL to Mouth of St. Mary’s River…1-3 ft

Indian Pass to Mexico Beach…1 to 3 ft. Florida Keys…1-2 ft