000 WTPZ42 KNHC 060250 TCDEP2 Hurricane Kay Discussion Number 7 NWS National Hurricane Center Miami FL EP122022 900 PM MDT Mon Sep 05 2022 Kay was upgraded to a hurricane earlier today based on valuable data that was received from the Air Force Hurricane Hunters just before the previous advisory issuance. The aircraft reported dropsonde data that supported a minimum pressure around 980 mb, along with flight-level winds of 85 kt at 850 mb and SFMR winds up to 71 kt in the eastern portion of the cyclone. There were some earlier hints of a ragged eye trying to emerge in visible imagery, but the center is still obscured by a small central dense overcast. The inner core structure of the cyclone does not appear to have improved much based on a couple of recent passive microwave overpasses, as some dry air has wrapped into the western and southern portions of the circulation. Based on the earlier aircraft data, the intensity of Kay is held at 70 kt for this advisory. The hurricane is moving west-northwestward at 285/9 kt. The track guidance for Kay over the next few days remains in good agreement. Kay is expected to turn northwestward on Tuesday and then north-northwestward by early Wednesday while moving toward or to the west of the Baja California peninsula. While the core of the storm is still forecast to remain offshore, the large wind field could bring tropical-storm-force winds to the southern portion of Baja California by early Wednesday. The hurricane is forecast to make its closest approach to the west-central portion of Baja California late Thursday into Friday. The official NHC forecast lies very close to the HFIP corrected consensus approach (HCCA) and has been nudged slightly to the right of the previous one. It is noted that the GFS and ECMWF still lie on the eastern edge of the guidance envelope. Kay has significantly strengthened today despite some moderate northeasterly deep-layer shear diagnosed by the SHIPS guidance over the system. This shear is forecast to diminish in a day or so, while Kay remains over very warm SSTs and in a moist and unstable environment. Thus, more strengthening is anticipated and Kay could approach major hurricane strength in 36-48 h. The official NHC forecast is very similar to the previous one and lies slightly above the IVCN aid and closer to HCCA. By early Thursday, drier air and cooler SSTs at higher latitudes will cause Kay to begin weakening. The cyclone is forecast to lose its organized convection and become a post-tropical low by day 5. The government of Mexico has extended the Tropical Storm Watch northward from Puerto San Andresito to Punta Abreojos. Additional tropical storm or hurricane watches or warnings could be necessary for portions of Baja California later tonight or on Tuesday. KEY MESSAGES: 1. Gusts to tropical-storm-force and rough surf along the coast of southwestern Mexico are expected through Tuesday. In addition, heavy rainfall from Kay could lead to flash flooding, including landslides, across portions of the Mexican Riviera and western Mexico through Wednesday night. 2. Tropical storm conditions are possible across the southern Baja California peninsula by early Wednesday, where a Tropical Storm Watch has been issued. 3. While the details of the long-range track and intensity forecasts remain uncertain, there is increasing risk of significant wind, surf, and rainfall impacts across the central portion of the Baja California peninsula later this week. A tropical storm or hurricane watch could be issued for that region by Tuesday. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 16.0N 108.1W 70 KT 80 MPH 12H 06/1200Z 17.1N 109.6W 80 KT 90 MPH 24H 07/0000Z 18.3N 111.2W 90 KT 105 MPH 36H 07/1200Z 19.9N 112.5W 95 KT 110 MPH 48H 08/0000Z 21.7N 113.4W 95 KT 110 MPH 60H 08/1200Z 23.7N 114.1W 85 KT 100 MPH 72H 09/0000Z 25.6N 115.0W 75 KT 85 MPH 96H 10/0000Z 28.5N 116.8W 50 KT 60 MPH 120H 11/0000Z 30.0N 120.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Reinhart