ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Hurricane Norma Discussion Number 13 NWS National Hurricane Center Miami FL EP172023 300 PM MDT Fri Oct 20 2023 After a brief period of weakening earlier today, data from the Air Force Hurricane Hunters this afternoon indicate that Norma has strengthened back to a major hurricane. The aircraft data showed maximum 700-mb flight-level winds of 124 kt, with peak SFMR winds of 104 kt in the northeast quadrant. Based on these data, the initial intensity is raised to 105 kt. The eyewall is open to the southeast based on aircraft reports. The eye signature has become better defined over the past few hours in radar data from Los Cabos, Mexico, as new bursts of intense inner core convection have developed. The radar data show that the outer rainbands of Norma are beginning to spread over southern portions of Baja California Sur. In the short term, the renewed inner core of Norma could allow the hurricane to resist some of the negative influences of southerly shear and drier air in the surrounding environment. The updated NHC forecast still shows some weakening but is higher than the previous one during the first 24-36 h of the forecast, based largely on the higher initial intensity. Land interaction with the Baja California peninsula, along with the previously described negative factors, should induce a more steady weakening trend through early next week while Norma approaches mainland Mexico. Scatterometer data and aircraft fixes show that Norma has moved slightly left-of-track today, and its initial motion is 330/7 kt. The hurricane is expected to turn toward the north-northwest and north during the next day or so while it moves between a mid- to upper-level trough to its northwest and a mid-level ridge to its east. This will bring the center of Norma over the southern tip of Baja California Sur within the hurricane warning on Saturday. The track models have again trended westward this cycle, and the updated NHC forecast is nudged in that direction during the next 24-36 h. Then, the models generally agree that Norma will turn northeastward and approach the coast of Sinaloa in western Mexico, although there are still notable speed differences between the various track models. This portion of the NHC forecast is similar to the previous one, although a bit slower based on the latest consensus aids. Norma is forecast to move inland along the coast of Sinaloa on Monday and quickly dissipate thereafter over the terrain of western Mexico. Key Messages: 1. Norma is expected to bring hurricane conditions and a dangerous storm surge to portions of the far southern Baja California peninsula within the hurricane warning area on Saturday. Preparations to protect life and property should be rushed to completion. 2. Heavy rains from Norma will begin to impact the far southern portions of Baja California Sur today and continue through Sunday, with heavy rains reaching Sinaloa on Saturday. This rainfall will produce flash and urban flooding, along with possible mudslides in areas of higher terrain. 3. Norma is forecast to approach the west coast of Mexico as a tropical storm on Sunday and Sunday night, and a Tropical Storm Watch is in effect for a portion of that area. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 20.1N 109.8W 105 KT 120 MPH 12H 21/0600Z 21.2N 110.0W 100 KT 115 MPH 24H 21/1800Z 22.6N 110.1W 85 KT 100 MPH 36H 22/0600Z 23.4N 109.7W 70 KT 80 MPH 48H 22/1800Z 23.9N 109.0W 60 KT 70 MPH 60H 23/0600Z 24.2N 108.1W 50 KT 60 MPH 72H 23/1800Z 24.6N 107.1W 35 KT 40 MPH...INLAND 96H 24/1800Z...DISSIPATED $$ Forecaster Reinhart NNNN