000 WTPZ42 KNHC 070856 TCDEP2 Hurricane Kay Discussion Number 12 NWS National Hurricane Center Miami FL EP122022 300 AM MDT Wed Sep 07 2022 Kay appears to be slightly better organized in satellite imagery this morning with an eye that has become a little better defined and a convective band with cloud tops as cold as -70 to -80C wrapping around the center. There is a larger-than-normal spread between the subjective and objective Dvorak estimates this morning so there is more uncertainty regarding the hurricane's initial intensity than usual. The initial intensity has been raised to 85 kt, commensurate with the recent increase in organization. An Air Force Reserve reconnaissance aircraft is scheduled to investigate Kay this afternoon. Kay is located over sea surface temperatures of 28-29 degrees Celsius, and the vertical wind shear has decreased over the past 24 hours and become less than 10 kt over the storm. These conditions should allow for some strengthening today. By tonight, Kay will be moving over decreasing SSTs, and a weakening trend should begin shortly thereafter. However, Kay is expected to remain a hurricane when it passes near the west-central coast of the Baja peninsula on Thursday and Thursday night. After that time, sharply decreasing SSTs should produce a faster rate of weakening, and Kay is forecast to become a post-tropical cyclone after it passes near northern Baja California by day 4. The NHC intensity forecast is above most of the guidance at 12 hours, and then closely follows the SHIPS model during the weakening phase of the forecast. Kay has turned north-northwestward and is moving 330/10 kt. A ridge to the east of Kay should steer the storm north-northwestward during the next few days. This will take the core of the hurricane near the west-central coast of Baja California on Thursday and Friday. After that time, low-level ridging to the north of Kay should cause it to turn westward as it weakens. The GFS and its ensemble mean remain along the east side of the guidance envelope while the ECMWF is closer to the center. The NHC track lies between those typically reliable models and is between the TVCE and HFIP consensus aids. The updated track is slightly to the right of the previous advisory. Kay is a very large tropical cyclone. It is producing an extensive area of high seas, with swells affecting portions of southwestern Mexico and the southern Baja California peninsula. Although Kay is likely to weaken before it makes its closest approach to the west-central coast of the Baja peninsula, it is forecast to remain a large and dangerous hurricane through that time. In addition, high wind, surf, and rainfall impacts will extend far from the center so users should not focus on the exact forecast track. KEY MESSAGES: 1. Heavy rainfall could lead to flash flooding, including landslides, across the Baja California peninsula and portions of mainland northwestern Mexico through Saturday morning. Flash flooding is possible across the peninsular ranges of Southern California Friday night into Saturday morning. 2. Hurricane conditions are expected along portions of the west-central Baja California coast on Thursday and Thursday night, and a hurricane warning is in effect for that area. 3. Tropical storm conditions are expected over portions of the Baja California peninsula beginning this morning, where a Tropical Storm Warning is in effect. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 20.2N 112.0W 85 KT 100 MPH 12H 07/1800Z 21.6N 112.8W 90 KT 105 MPH 24H 08/0600Z 23.7N 113.6W 85 KT 100 MPH 36H 08/1800Z 26.0N 114.5W 80 KT 90 MPH 48H 09/0600Z 27.9N 115.6W 70 KT 80 MPH 60H 09/1800Z 29.7N 116.8W 55 KT 65 MPH 72H 10/0600Z 30.8N 118.2W 40 KT 45 MPH 96H 11/0600Z 31.2N 120.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 12/0600Z 30.1N 121.6W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown