Tropical Storm Bertha was moving toward the west over the northern Gulf of Mexico on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Bertha was located at latitude 29.4°N and longitude 87.7°W which put the center about 100 miles (160 km) south-southeast of Mobile, Alabama. Bertha was moving toward the west at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 995 mb.
A Tropical Storm Warning is in effect for the portion of the coast from the Bay County/Gulf County Line in Florida to Morgan City, Louisiana. A Tropical Storm Warning is in effect for New Orleans. A Tropical Storm Warning is in effect Lake Pontchartrain.
A Tropical Storm Watch is in effect for Lake Maurepas. A Tropical Storm Watch is in effect for the portion of the coast from Morgan City to Cameron, Louisiana.
Tropical Storm Bertha was maintaining its intensity on Tuesday evening in spite of strong northeasterly winds in the upper troposphere. Those winds were causing moderate vertical wind shear, but the wind shear was not strong enough to cause Bertha to weaken. The vertical wind shear was affecting the structure of Tropical Storm Bertha. Thunderstorms were occurring in bands in the southern half of Tropical Storm Bertha. Bands in the northern half of Bertha’s circulation consisted primarily of showers and lower clouds. Storms near the center of Bertha generated upper level divergence that pumped mass away to the south and west of the tropical storm. The removal of mass in the upper levels was equal to the convergence of mass in the lower levels of the atmosphere. So, the surface pressure was remaining constant on Tuesday evening.
The strongest winds were occurring in the southeastern part of Tropical Storm Bertha. Winds to tropical storm force extended out 115 miles (185 km) in the eastern side of Bertha’s circulation. Winds to tropical storm force extended out 45 miles (75 km) in the western side of Tropical Storm Bertha.
Tropical Storm Bertha will move into an environment that will become unfavorable for intensification during the next 24 hours. Bertha will move over water where the Sea Surface Temperatures are near 29°C. It will move under southeastern part of an upper level ridge that is centered over the South Central U.S. The upper level ridge will produce northeasterly winds that will blow across the top of Bertha’s circulation. Those upper level winds are forecast to get stronger on Wednesday. Those stronger winds will cause the vertical wind shear to increase. Tropical Storm Bertha could maintain its intensity during the next few hours. Bertha is likely to weaken when the vertical wind shear increases.
Tropical Storm Bertha will move around the southern side of a high pressure system that is over the southern Mississippi River Valley. The high pressure system will steer Bertha toward the west during the next 24 hours. On its anticipated track, the center of Tropical Storm Bertha will reach southeastern Louisiana on Wednesday.
Tropical Storm Bertha will bring gusty winds to the central Gulf Coast. Since the strongest winds are in the southeastern part of Bertha’s circulation, those winds will remain over the Gulf of Mexico during the next 24 hours. Bands on the northern side of Tropical Storm Bertha could drop locally heavy rain over parts of Northwest Florida, southern Alabama, southern Mississippi, and southern Louisiana. Bertha could also cause a storm surge of up to 4 feet (1 meter) along parts of the coast of southeastern Louisiana.