Tropical Storm Bertha Strengthens to 50 mph as Gulf Coast Watches and Warnings Expand

Q: Can a massive Saharan dust cloud stop Tropical Storm Bertha from becoming a major Gulf Coast hurricane?

Probably yes, but not by itself. Forecasters say the environment around Tropical Depression Two, expected to become Bertha, is unfavorable for major strengthening. The key factors are dry air, increasing wind shear and the storm’s broad, poorly organized circulation. A Saharan dust plume matters because it carries very dry, stable air that can choke off thunderstorms and make it harder for a tropical system to build a strong core. That same air mass is also often linked with stronger winds aloft, which increase shear and disrupt storm structure. That said, the dust cloud is not a guarantee that Bertha cannot strengthen. Tropical systems can still intensify if they find a pocket of warm water and remain organized long enough, especially if they stay farther south over the Gulf. The National Hurricane Center outlook indicates gradual strengthening is likely, but rapid intensification is not the favored scenario. Current projections keep Bertha closer to a modest tropical storm, with some forecasts near 50 mph around Louisiana, rather than a major hurricane. So the best reading of the forecast is that Saharan dust is one important reason Bertha is unlikely to become a major Gulf Coast hurricane, but it is part of a broader set of hostile conditions, especially wind shear. Residents should not focus only on category risk: even a weaker tropical storm can still bring dangerous surf, rip currents, storm surge, flooding rain and isolated tornadoes along the Gulf Coast.

3 articles · Updated · WESH 2 Orlando · Jul 21

Bertha reached 50 mph winds and 998 mb pressure Tuesday morning, sitting about 110 miles south of Panama City as it resumed a northwestward track.
Warnings and watches remain posted from the Florida Panhandle to Louisiana, including a storm surge watch from the Alabama-Florida border to the mouth of the Mississippi River; more alerts are likely later Tuesday.
Tropical-storm conditions are expected in warning areas by late Tuesday into Wednesday, with Bertha forecast to move near or along the northern Gulf Coast over the next several days.
Rainfall of 2 to 4 inches, with isolated totals near 8 inches, could trigger flash flooding from western Florida to southern Louisiana, especially in urban areas.