313 WTPZ42 KNHC 080851 TCDEP2 Hurricane Kay Discussion Number 16 NWS National Hurricane Center Miami FL EP122022 300 AM MDT Thu Sep 08 2022 The satellite presentation of Kay has gradually degraded overnight with the eye becoming less defined, and the deepest convection confined to the southeastern and eastern portions of the circulation. An Air Force Reserve reconnaissance aircraft that investigated Kay overnight has measured peak 700-mb flight-level winds of 78 kt. Unfortunately the SFMR data appeared unrepresentative as compared to corresponding dropsonde surface winds and recent scatterometer data. As a result, there is higher uncertainty in how much the flight-level winds are mixing to the surface. The initial intensity has been conservatively reduced to 75 kt, which is a blend of the flight-level reduced winds, and recent satellite intensity estimates. The aircraft reported a minimum pressure of 974 mb on its final pass through the center. Kay has crossed the 26 degree Celsius isotherm and will be traversing progressively cooler SSTs over the next couple of days. That, along with a gradually drying mid-level air mass, is expected to cause gradual weakening over the next couple of days. However, Kay is forecast to remain a hurricane when it passes near or over the west-central coast of the Baja California peninsula later today, and remain a tropical storm as it passes just west of the northwestern portion of the peninsula on Friday. Simulated satellite imagery from the global models suggest the convection will wane on Saturday, and Kay is forecast to become post-tropical at that time. The new NHC intensity forecast calls for slightly faster rate of weakening than before, and is near the IVCN and HCCA consensus aids. Kay continues to move north-northwestward or 345/12 kt. A mid-level ridge to the east of Kay should steer it on a north-northwestward heading during the next 24 to 36 hours. After that time, a weaker and more vertically shallow Kay is expected to turn more westward, and eventually southward to the southeast of a low-level ridge over the eastern Pacific. The NHC track forecast lies near the HFIP corrected consensus model, and is quite similar to the previous official forecast. Kay is a very large tropical cyclone. It is producing an extensive area of high seas, with swells affecting portions of southwestern Mexico, the Gulf of California, and the Baja California peninsula. Although Kay is likely to weaken before it makes landfall or moves very close 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. As the center of Kay passes near or over the Baja California peninsula, heavy rainfall could lead to flash flooding, including landslides, across the Baja California peninsula and portions of mainland northwestern Mexico through Saturday morning. Flash, urban, and small stream flooding is possible across Southern California, especially in and near the peninsular ranges, and Southwest Arizona, Friday into Saturday. 2. Hurricane conditions are expected along portions of the west-central Baja California coast later this morning through this evening, and a hurricane warning is in effect for that area. 3. Tropical storm conditions are occurring over portions of the Baja California peninsula, and these conditions are expected to spread northward during the next day or so, where a Tropical Storm Warning is in effect. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 24.5N 113.4W 75 KT 85 MPH 12H 08/1800Z 26.5N 114.1W 65 KT 75 MPH 24H 09/0600Z 28.7N 115.4W 55 KT 65 MPH 36H 09/1800Z 30.5N 116.8W 45 KT 50 MPH 48H 10/0600Z 31.4N 118.4W 40 KT 45 MPH 60H 10/1800Z 31.7N 119.5W 35 KT 40 MPH...POST-TROPICAL 72H 11/0600Z 31.7N 120.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 12/0600Z 30.3N 120.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 13/0600Z 28.7N 120.0W 15 KT 15 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown