ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Tropical Depression Norma Discussion Number 23 NWS National Hurricane Center Miami FL EP172023 300 AM MDT Mon Oct 23 2023 Norma has weakened to a tropical depression as the cyclone has been void of deep convection since yesterday afternoon. A couple of ASCAT overpass between 0354 and 0441 UTC showed peak winds in the 31 to 33 kt range, and assuming additional weakening has occurred since that time, the initial intensity has been lowered to 30 kt. Dry mid-level air has been entrained into the circulation from the northwest, and given the current strong shear over the system, it appears unlikely that significant deep convection will return. Norma should move onshore the coast of western mainland Mexico later this morning, and it is expected to rapidly weaken and either become post-tropical or dissipate today over the high terrain of western Mexico. Norma took a southeastward jog overnight, but it appears to have resumed an eastward motion at about 6 kt. A general eastward to motion is expected to continue until dissipation occurs. The more southward initial position required a southward adjustment of the track forecast, but it otherwise remains near the center of the guidance envelope. Heavy rainfall associated flooding remains the primary threat with this system. Key Messages: 1. Heavy rainfall associated with Norma will diminish across portions of western Mexico today. Additional isolated heavy rainfall may produce isolated flash flooding and mudslides in areas of higher terrain. 2. Gusty winds are possible along the coast of Sinaloa Mexico this morning. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 24.5N 108.4W 30 KT 35 MPH 12H 23/1800Z 24.7N 107.3W 25 KT 30 MPH...POST-TROP/INLAND 24H 24/0600Z...DISSIPATED $$ Forecaster Brown NNNN
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Page last modified: Monday, 18-Dec-2023 12:10:25 UTC