The potential exists for the development of a tropical cyclone over the northern Gulf of Mexico this week. A low pressure system was over Georgia on Monday afternoon. The low was drifting slowly southward, but it was forecast to move more toward the south-southwest during the next two days. Several numerical models were predicting that the low pressure system would strengthen into a tropical depression or a tropical storm after it moves over the northern Gulf of Mexico later this week. The National Hurricane Center was indicating that the low pressure system, currently designated as Invest 92L, had a 30% probability of developing into a tropical cyclone during the next two days and an 80% probability of developing into a tropical cyclone during the next five days.
The low pressure system exhibited a surface circulation on Monday afternoon, but the wind speed was near 15 m.p.h. (25 km/h). Bands of showers and thunderstorms formed during the daytime heating over land, but they weakened at night. There was also a counterclockwise rotation in the lower and middle troposphere which may have been the remnants of a mesoscale convective vortex (MCV), which developed over the Middle Mississippi River Valley a few days ago. The low was not generating upper level divergence on Monday afternoon.
If the low pressure system does move over the northern Gulf of Mexico on Tuesday or Wednesday, it will move into an environment more favorable for the development of a tropical depression. The Sea Surface Temperature of the water in the northeastern Gulf of Mexico is near 30°C. The low pressure system will move southeast of an upper level ridge over the southern U.S. The ridge will produce northeasterly winds, but the winds will be relatively weak and the vertical wind shear will not be too strong. More thunderstorms are likely to develop when the low pressure system moves over the warm water. If those thunderstorms generate upper level divergence that pumps mass away, then the surface pressure will decrease and a tropical depression will form.
The upper level ridge is forecast to steer the low pressure system toward the west after it moves over the Gulf of Mexico later this week. On its anticipated track the low pressure system will move slowly toward the coast of Louisiana and Texas. The future intensity of the system will be determined by how far the system moves into the Gulf of Mexico. If the low pressure system takes a track along or near the north coast of the Gulf of Mexico, then it will likely become a tropical depression or a weak tropical storm. Even if the low only strengthens into a tropical depression, it could drop heavy rain and the potential for flooding exists along the northern Gulf Coast. If the low pressure system moves farther out into the Gulf of Mexico and remains over warm water for a longer period, then it might intensify into a hurricane. Residents along the Gulf Coast should monitor this system carefully.