000 WTPZ42 KNHC 040852 TCDEP2 Hurricane Lorena Discussion Number 10 NWS National Hurricane Center Miami FL EP122025 200 AM MST Thu Sep 04 2025 Lorena has become less organized since the last advisory due to the impacts of increasing vertical shear and decreasing sea surface temperatures underneath the hurricane. Earlier microwave imagery indicated that the eyewall had broken open, and current conventional imagery shows that the low-level center is now located near the southwestern edge of the convective mass. The various satellite intensity estimates are now trending down, and based on this the initial intensity is reduced to a possibly generous 70 kt. The initial motion is now a slower 320/7 kt. Lorena is expected to turn northward with a further decrease in forward speed later today as the cyclone moves farther into a break in the subtropical ridge. After that, the guidance is now considerably slower in moving Lorena to the north-northeast with the 00Z GFS now taking 60 h to reach Baja California Sur. The NHC forecast track is again slowed down significantly and blends the previous forecast with the new consensus models and the 00Z GFS. It should be noted that in contrast to the right turn of the GFS and the regional hurricane models, the ECMWF and Canadian models continue to show a left turn as Lorena approaches the coast that would keep the center offshore until the cyclone dissipates. Lorena should rapidly weaken in the increasingly unfavorable environment, with the cyclone now forecast to weaken to a tropical storm in 12 h or less. After that, the simulated satellite imagery from the 00Z GFS and ECMWF shows the cyclone should stop producing organized convection no later than 48 h, and this could happen earlier. The new intensity forecast now shows the system decaying to a remnant low by 48 h. Whether the system crosses Baja or stays over the cold Pacific waters, it is expected to dissipate completely by 96 h. Although Lorena is forecast to rapidly weaken, abundant moisture will continue to stream northeastward away from the cyclone. Because of that, there is still a significant risk of heavy rainfall and flash flooding across portions of Baja California Sur, Sonora, and southern Arizona and New Mexico. Key Messages: 1. Heavy rainfall associated with Lorena will continue to impact Baja California Sur and Sonora Mexico through Friday. This will increase the risk of life-threatening flash floods and mudslides across northwest Mexico. 2. Moisture from Lorena will contribute to heavy rainfall concerns across Arizona and New Mexico through Saturday. Isolated to scattered instances of flash flooding are possible across Arizona into Saturday. 3. The center of Lorena is forecast to move parallel to, but offshore of, the southwest coast of the Baja California Peninsula today, and then move closer to the west-central coast of the peninsula tonight and Friday. Regardless of the exact track, tropical storm conditions are likely along portions of the coast of Baja California Sur where a Tropical Storm Warning is in effect. Tropical storm conditions are also possible late Friday along the east coast of the Baja California peninsula, where a Tropical Storm Watch is in effect. 4. Life-threatening surf and rip current conditions will affect portions of the southern and western coasts of Baja California Sur during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 24.0N 113.7W 70 KT 80 MPH 12H 04/1800Z 24.7N 114.2W 60 KT 70 MPH 24H 05/0600Z 25.4N 114.3W 45 KT 50 MPH 36H 05/1800Z 26.1N 113.9W 35 KT 40 MPH 48H 06/0600Z 26.7N 113.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 06/1800Z 27.3N 113.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 07/0600Z 28.0N 112.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 08/0600Z...DISSIPATED $$ Forecaster Beven
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