000 WTPZ45 KNHC 091451 TCDEP5 Hurricane Olaf Discussion Number 8 NWS National Hurricane Center Miami FL EP152021 900 AM MDT Thu Sep 09 2021 Recent microwave imagery shows that Olaf's structure has improved considerably during the past 6 hours, and it now has well-defined eye. The eye is also now evident in radar imagery from Cabo San Lucas. Although an eye is not yet evident in infrared or visible imagery, satellite intensity estimates had increased and supported an intensity of 60-65 kt at 1200 UTC. Given the continued impressive satellite appearance since then, the estimated intensity is 65 kt for this advisory, making Olaf a hurricane. Olaf has a microwave ring structure that is known to indicate intensification in the short term. The wind shear that previously affected the hurricane seems to have lessened and the environment should also support further strengthening today. The hurricane is therefore forecast to quickly intensify during the next 12 h or so while it approaches the southern tip of the Baja California peninsula. After that, interaction with land and cold sea surface temperatures should cause the cyclone to quickly weaken over the weekend. Olaf is forecast to become post-tropical in about 60 h as it moves farther away from land. The NHC intensity forecast is above the previous advisory, and is above most of the guidance through 24 h. Beyond that, there have been only slight adjustments to the official intensity forecast, which is based on the multi- model consensus. The track forecast has shifted closer to the southern Baja California peninsula. In line with the intensity forecast, the NHC forecast now slightly favors the stronger GFS and regional hurricane models, compared to the weaker ECMWF, but is still near the HCCA and TVCN consensus aids. Olaf is moving north-northeast but should turn northwestward later today, steered by a mid-level ridge centered over the western United States. The models with a stronger hurricane show Olaf turning slightly slower, and bring the center very near or even over Baja California Sur tonight. As Olaf weakens it should begin to be steered by lower-level flow, which will cause it to eventually turn westward and then southwestward as it moves away from land early next week. Key Messages: 1. Olaf is forecast to pass very near or over the southern portion of Baja California Sur tonight and Friday, and hurricane conditions are likely within the hurricane warning area tonight. Tropical storm conditions are expected to begin within the hurricane warning area this afternoon, and preparations should be rushed to completion. 2. Heavy rains associated with Olaf are expected across portions of southern Baja California Sur through Friday. This will pose a threat of significant and life-threatening flash flooding and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 21.2N 108.3W 65 KT 75 MPH 12H 10/0000Z 22.2N 109.2W 75 KT 85 MPH 24H 10/1200Z 23.3N 110.7W 65 KT 75 MPH 36H 11/0000Z 24.0N 112.1W 60 KT 70 MPH 48H 11/1200Z 24.1N 113.5W 45 KT 50 MPH 60H 12/0000Z 23.8N 114.7W 35 KT 40 MPH...POST-TROPICAL 72H 12/1200Z 23.2N 116.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 13/1200Z 21.5N 119.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 14/1200Z 21.0N 122.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster D. Zelinsky