Idalia roared into the Gulf of Mexico just after midnight local time on August 29, 2023, and within hours, strengthened to a category 1 hurricane. The hurricane is forecast to rapidly intensify before slamming into Florida’s coast near Apalachee Bay on the morning of August 30.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this image of Idalia around 11:35 a.m. Eastern Time on August 29. At this time, Idalia was moving north and the National Hurricane Center (NHC) reported wind speeds of about 85 miles (135 kilometers) per hour.
Officials in Florida issued evacuation orders for 22 counties in the state with mandatory evacuations along the coast of the Big Bend region—where Florida’s panhandle curves to meet the peninsula, and where Idalia is forecasted to make landfall. Dangerous storm surge of up to 10-15 feet above ground-level is forecast in this area, according to the NHC.
Fueled by unusually warm water in the Gulf of Mexico, Idalia is expected to rapidly intensify into a category 3 storm—with sustained winds of at least 111 miles (179 kilometers) per hour—before reaching Florida’s shores. Rapid intensification is when winds increase by at least 35 miles per hour (55 kilometers per hour) in a 24-hour period. Some key ingredients for rapid intensification are high sea surface temperatures, excess ocean heat content (a measure of the water temperature below the surface), and low vertical wind shear.
The map above shows sea surface temperatures on August 27 based on data from the Multiscale Ultrahigh Resolution Sea Surface Temperature (MUR SST) project, a NASA Jet Propulsion Laboratory effort that blends measurements of sea surface temperatures from multiple NASA, NOAA, and international satellites, as well as ship and buoy observations.
Meteorologists generally agree that sea surface temperatures should be above 27.8 degrees Celsius (82 degrees Fahrenheit) to sustain and intensify hurricanes, cyclones, and typhoons. Surface waters above that threshold are represented in red on the map.
“Waters throughout the eastern Gulf of Mexico remain warmer than 31 degrees C, which is around 1-2 degrees Celsius above average for this date,” said Patrick Duran, a hurricane expert at NASA’s Short-Term Prediction Research and Transition (SPoRT) project, based at Marshall Space Flight Center. “This very warm water will provide more energy to the storm than would be available if temperatures were closer to average.”
NASA’s Earth Applied Sciences Disasters program area has been activated in support of Hurricane Idalia. As new information becomes available, the team will be posting maps and data products on its open-access mapping portal.
NASA Earth Observatory images by Lauren Dauphin and Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and sea surface temperature data from the Multiscale Ultrahigh Resolution (MUR) project. Story by Emily Cassidy.