000 WTPZ42 KNHC 050252 TCDEP2 Tropical Storm Kay Discussion Number 3 NWS National Hurricane Center Miami FL EP122022 1000 PM CDT Sun Sep 04 2022 The structure of Kay has slightly improved in satellite imagery this evening. Deep convection has increased near the center, with a more defined curved band over the southern and western portions of the circulation. Earlier ASCAT data showed several 35-kt wind vectors in the northeastern quadrant of the storm, and objective satellite estimates have increased since TAFB provided a T2.5/35 kt Dvorak classification at 00 UTC. Therefore, the initial intensity is raised slightly to 40 kt for this advisory. Kay has moved a bit right of the previous forecast track, but its initial motion is still west-northwestward, or 295/12 kt. This general motion is expected to continue for the next day or two as the core of the cyclone passes well south of the coast of southwestern Mexico. By Tuesday, the tightly clustered guidance agrees that Kay will turn toward the northwest and then the north-northwest, moving in the general direction of the Baja California peninsula. The official NHC forecast track is virtually unchanged from the previous one beyond 36 h, and closely follows the HCCA and TVCE consensus aids. There is increased spread in the GFS and ECMWF ensemble members later this week as Kay moves northward. Users are reminded not to focus on the exact details of the long-range forecast, as track errors on average increase with time. The environmental conditions appear favorable for strengthening during the next few days. Although Kay is currently contending with some moderate northeasterly wind shear, a moist and unstable atmosphere over very warm sea-surface temperatures (> 29C) should allow the storm to intensify through the middle of the week. The northeasterly shear is forecast to weaken beyond 48 h, which would be even more conducive for significant strengthening as suggested by some of the intensity guidance. The NHC intensity forecast generally lies between the IVCN and HCCA aids, and it shows Kay becoming a hurricane by early Tuesday and continuing to intensify into Wednesday. Beyond 72 h, cooler SSTs are expected to induce a weakening trend through the rest of the forecast period. Tropical Storm or Hurricane Watches could be required tonight or on Monday for portions of the Baja California peninsula, and interests there should closely monitor the latest forecast updates. KEY MESSAGES: 1. Although the center of Kay is expected to stay offshore, heavy rainfall could lead to localized flash flooding in portions of southwestern Mexico over the next few days. 2. Kay is forecast to strengthen into a hurricane while it moves northward toward the Baja California peninsula later this week. While the details of the long-range track and intensity forecasts are uncertain, there is a risk of wind and rainfall impacts in the Baja California peninsula during the middle and latter parts of the week. Interests there should closely monitor updates to the forecast as tropical storm or hurricane watches could be required tonight or on Monday. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 15.6N 103.8W 40 KT 45 MPH 12H 05/1200Z 16.0N 105.4W 50 KT 60 MPH 24H 06/0000Z 16.5N 107.2W 60 KT 70 MPH 36H 06/1200Z 17.5N 109.0W 70 KT 80 MPH 48H 07/0000Z 18.9N 110.5W 80 KT 90 MPH 60H 07/1200Z 20.7N 111.8W 85 KT 100 MPH 72H 08/0000Z 22.5N 112.7W 85 KT 100 MPH 96H 09/0000Z 26.2N 114.3W 70 KT 80 MPH 120H 10/0000Z 29.3N 116.5W 50 KT 60 MPH $$ Forecaster Reinhart