|
Show Selection: |
| #1198355 (Received by flhurricane at: 11:00 AM 14.Sep.2024) TCDAT2 Tropical Storm Gordon Discussion Number 13 NWS National Hurricane Center Miami FL AL072024 1100 AM AST Sat Sep 14 2024 Gordon`s center is exposed and located west of its deep convection. This structure is a symptom of the moderate westerly vertical wind shear that continues to plague the tropical storm. Gordon is also struggling with the entrainment of dry and stable airmass. Despite these environmental challenges, a recent scatterometer pass shows the cyclone maintaining 40 kt maximum sustained winds. This data is the basis for the initial intensity of this advisory, and agrees with a blend of the objective and subjective estimates. The scatterometer pass also shows a lopsided wind field, with tropical storm force winds limited to the northern semicircle of Gordon. In the southern semicircle, winds are weak and the vortex shows signs of elongation. The cyclone continues to move into a dry and stable airmass, which in conjunction with the ongoing shear is forecast to induce weakening today and tonight. Gordon is forecast to become a tropical depression on Sunday. Thereafter, the forecast maintains the cyclone as a tropical depression through the early part of next week, but it is possible that the system degenerates into a remnant low or a surface trough during that time. In fact, the GFS model indicates convection could collapse as soon as tonight or early Sunday. The ECMWF model maintains pulsing convection a bit longer. By the middle of next week, the environment should become less hostile and allow for some re-strengthening of Gordon. The intensity forecast is largely unchanged from the previous advisory and remains on the lower end of the guidance beyond 72 h due to the uncertain future of the cyclone. Gordon is tracking westward 280/8 kt, and a gradual turn toward the west-southwest with a slower forward speed is forecast over the next couple of days, in good agreement with the latest track guidance. Model spread increases beyond 72 h due to differences in intensity and the overall structure of Gordon at that time. The current forecast continues the system slowly west-southwestward due to lack of steering flow. Towards the end of the forecast period, an approaching shortwave trough will weaken the mid-level subtropical ridge and would allow the system to turn northward. The updated track forecast is close to the previous advisory near the simple consensus aids, and shows a gradual turn toward the northwest and north beyond Day 3. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 20.1N 41.7W 40 KT 45 MPH 12H 15/0000Z 20.0N 43.0W 35 KT 40 MPH 24H 15/1200Z 19.9N 44.7W 30 KT 35 MPH 36H 16/0000Z 19.7N 46.1W 30 KT 35 MPH 48H 16/1200Z 19.6N 47.6W 30 KT 35 MPH 60H 17/0000Z 19.5N 49.0W 30 KT 35 MPH 72H 17/1200Z 19.5N 49.8W 30 KT 35 MPH 96H 18/1200Z 20.0N 50.9W 35 KT 40 MPH 120H 19/1200Z 21.5N 50.9W 40 KT 45 MPH $$ Forecaster Kelly/Mahoney |
