619 WTPZ45 KNHC 100843 TCDEP5 Hurricane Olaf Discussion Number 11 NWS National Hurricane Center Miami FL EP152021 300 AM MDT Fri Sep 10 2021 Olaf made landfall very near San Jose del Cabo, Baja California Sur, around 0300 UTC based on radar images from Los Cabos and surface pressure reports from the region. Since then, the radar data showed that the center crossed the peninsula and re-emerged just off the southwestern coast a few hours ago with heavy rainbands continuing to stream northward across the area between Cabo San Lucas and La Paz. Assuming some weakening over land, the initial intensity is set at 75 kt, which matches the latest Dvorak Current Intensity estimates from TAFB and SAB. The hurricane continues to move toward the northwest but has turned more to the left, or 315/11 kt. A strong mid-level high centered over the southern Rockies is forecast to build westward over the Pacific during the next few days, which should cause Olaf to turn westward by 36 hours and then southwestward by 60 hours until the end of the forecast period. On this track, Olaf will move along the southwestern coast of Baja California Sur for the next 12-18 hours but then turn westward away from land by tonight. This part of the forecast is unchanged from the previous advisory. There is some disagreement among the models on how far south Olaf will move on days 3 through 5 (as a remnant low), and the new NHC forecast has been nudged southward at those times toward the GFS, ECMWF, and HCCA model solutions. Olaf's proximity to the mountainous terrain of the Baja California peninsula during the next 12 to 18 hours will likely cause additional steady weakening, and the winds are forecast to fall below hurricane force by this evening. The storm will then move over waters colder than 26 degrees Celsius when it turns west of Cabo San Lazaro tonight, which should spur additional weakening. The SHIPS and LGEM models appear to be keeping Olaf's winds too high for the next day or so, and as a result the NHC intensity forecast is set below the HCCA consensus aid, closer to the GFS and ECMWF intensity trends. In fact, model-simulated satellite imagery suggests that the cold water could cause all of Olaf's deep convection to dissipate in 36-48 hours, and the cyclone is therefore forecast to degenerate to a post-tropical cyclone by Saturday night. Key Messages: 1. Olaf is forecast to move along the southwestern coast of the Baja California peninsula today, with hurricane and tropical storm conditions continuing over southern portions of Baja California Sur through this evening. These winds should diminish tonight once Olaf weakens and turns westward away from land. 2. Heavy rains associated with Olaf are expected across portions of southern Baja California Sur today. This will pose a threat of significant and life-threatening flash flooding and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 23.7N 110.7W 75 KT 85 MPH...NEAR THE COAST 12H 10/1800Z 24.4N 111.9W 65 KT 75 MPH...NEAR THE COAST 24H 11/0600Z 24.7N 113.3W 55 KT 65 MPH 36H 11/1800Z 24.5N 114.5W 45 KT 50 MPH 48H 12/0600Z 23.9N 115.6W 35 KT 40 MPH...POST-TROPICAL 60H 12/1800Z 23.0N 116.9W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 13/0600Z 22.1N 118.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 14/0600Z 21.0N 120.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 15/0600Z 20.5N 122.7W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Berg