Semafor Signals
Florida’s hot oceans are strengthening Hurricane Idalia
The News
Hurricane Idalia made landfall in the U.S. state of Florida on Wednesday. Unusually high temperatures in the Gulf of Mexico have strengthened the Category 4 hurricane, which has prompted mass evacuations and is expected to flood low-lying areas.
SIGNALS
The extreme ocean temperatures recorded around Florida this summer are leading to the rapid intensification of hurricanes. The Gulf of Mexico isn’t just recording hot surface temperatures: Deeper water is also hot, which provides fuel for storms. If a hurricane approaching land increases its wind speeds by 35 miles per hour or more in a 24-hour period, it has hit rapid intensification — and that can be a huge risk for people in its path, who may not be expecting such a a strong storm.• 1
Scientific American, Hurricane Idalia Is Turning into a Monster Storm because of Heat in Gulf of Mexico
Idalia may break a record for how rapidly it intensified. Speaking to the Associated Press, MIT professor Kerry Emanuel said that there are few places on Earth so ripe for feeding a storm as the Gulf of Mexico is right now. Both human-caused climate change and El Niño, a weather phenomenon that impacts ocean temperatures and weather patterns, are increasing the temperatures of the oceans this year.• 2
Tropical Storm Franklin is also raging off the southeastern coast of the U.S. That storm has been downgraded from a Category 4 hurricane to a tropical storm, but it continues to threaten Bermuda.• 3 That both Franklin and Idalia have reached Category 4 so early in the hurricane season is significant: Meteorologist Philip Klotzbach posted on social media platform X Wednesday that only six other years — 1933, 1958, 1999, 2004, 2005, and 2010 — have seen two storms hit Category 4 by Aug. 30.• 4
