Is it merely another drippy week along the Gulf Coast—or perhaps the beginning of something much more significant? With the Atlantic hurricane season cranking up, everyone is following a large area of showers and thunderstorms chugging westward from the Florida Panhandle into the Gulf of Mexico. Over the weekend, the National Hurricane Center assigned the system, Invest 93L, a 40% chance of turning into a tropical depression or even the season’s next-named system, Dexter.
But here’s the catch: even if the system never is given a name, it’s got enough punch to pour deluging rain over Florida and the north-central Gulf Coast for days and pose an actual flood threat. Gulf sea surface temperatures continue to run way warmer than average, offering a powerful energy boost to whatever storm is able to get its act together. As described in a recent study, tropical cyclones live on warm sea surface temperatures and low wind shear, but this week’s case is more of a meteorological tug-of-war. Though the water is set up for storm formation, unpleasant upper-level winds are attempting to rip the system to shreds, keeping its intensity at bay—at least for now.
Forecast models divide evenly. The American GFS and European ECMWF models both indicate some likelihood of organization, but the result hinges on storm path. If it sticks close to the coastline, development will be muted; if it goes farther south out over the open ocean, it might intensify rapidly (Yahoo News). Either way, the actual headline isn’t wind—it’s water.
Flood potential is already revving up. Wednesday, the Florida-to-Louisiana Gulf Coast faces a Level 1 out of 4 flood rain risk from 1 to 3 inches of rain. The risk heightens to Level 2 Thursday for Alabama, Mississippi, and the southeastern part of Louisiana and by Friday to a Level 3 threat in the Baton Rouge region as the system stalls and rain bands repeatedly inundate the same neighborhoods. In the worst-case scenario, localized rain can amount to more than 7 inches in the vicinity of New Orleans (ABC News).
This summer season already is a record-setter. Daytona Beach, for instance, recently experienced 2.25 inches of rain pour down in one day, breaking a 1935 record. Since the ground is already water-soaked from previous rainstorms, even a relatively light rain could be lethal within mere moments, particularly if the storm becomes stalled.
Flooding is not just limited to the coast. As Defense Health Agency’s Dr. Eric Deussing points out, “This tragic event, far inland and unrelated to a hurricane, underscores how quickly remnants of tropical storms can become life-threatening.” Storms like Barry, which dumped 20 inches of rain and record river surges more than 100 miles inland, remind us starkly that tropical rain can lead to flash flooding, loss of power, and public health hazards hundreds of miles inland (DVIDS).
So what can the Gulf Coast population do to be one step ahead of the storm? The experts suggest that tropical storms should be given as much respect as hurricanes. Stock up with supplies, check your evacuation zone, and get copies of important documents in electronic and paper format. Installing the FEMA app and registering for local alerts can keep you informed as things move along. After the storm, avoid standing near floodwaters, watch for hidden dangers, and never operate generators indoors.
And regarding what powers these storms, fresh research shows that an increasing sea surface temperature and changing wind patterns are powering and intensifying tropical cyclones—a trend observed particularly in the Caribbean and Gulf of Mexico. While models such as GFS and ECMWF are very convenient, localized effects far too often depend on very minor deviation by a storm’s direction or speed.
For the time being, everyone continues to turn their eyes to the Gulf. Whether or not Dexter is named, the point is obvious: in today’s environment, even an “unnamed” storm can bring record amounts of rain and represent a serious flood threat. Preparing is not only smart—it’s necessary.
