Discussion: A low pressure system on the coast of Belize is associated with massive powerful thunderstorms this morning in the far western Caribbean Sea. The low pressure area drifts north of the Yucatan Peninsula late Friday night and becomes a subtropical depression by Saturday morning. Initially, this system is linked to a cold trough aloft and is not purely tropical. Subtropical storm Alberto forms Saturday night/Sunday morning in the north-central Gulf of Mexico still linked with the upper level trough. By later in the Holiday Weekend Alberto becomes a tropical storm backing into southeast Louisiana with high wind and heavy rain and slowly weakening turning north from there.
Fig. 1: Morning satellite view of the Gulf of Mexico. The projected evolution and track of Alberto is annotated.
Fig. 2: The NOAA/WPC 7-day rainfall forecast indicates 4-8 in. across most of the Southeast U.S.