000 WTPZ42 KNHC 191443 TCDEP2 Tropical Storm Gilma Discussion Number 5 NWS National Hurricane Center Miami FL EP072024 800 AM PDT Mon Aug 19 2024 Recent AMSR and SSMIS imagery indicate that Gilma's center is located near the northeast edge of its deep convection, with little deep convection present in its northeast quadrant. This is due, at least in part, to upper-level easterly winds that are causing some shear across the cyclone. A consensus of objective and subjective intensity estimates from SAB, TAFB, and UW-CIMSS support an initial intensity of 45 kt for this advisory, which also agree well with earlier ASCAT data. The aforementioned wind shear is expected to persist for at least another day or two, which should limit the potential for strengthening. After around 36 h, global models indicate the shear will begin to decrease, which should allow for more strengthening. The exact timing of this strengthening is still highly uncertain, with several global models suggesting it could begin near the 36 h mark, while the HWRF indicates it won't begin to strengthen until closer to 60 h. Regardless, there is a good chance that Gilma will become a hurricane at some point before the end of the week. No significant changes were made to the intensity forecast, which follows the HCCA and IVCN intensity models. The track forecast is also largely unchanged from the previous NHC advisory. Gilma is currently moving west near 12 kt. A ridge extending westward from the southwest United States should keep Gilma on a similar heading today. After that, the tropical storm may interact with another disturbance to its west, while a trough off the U.S. west coast will begin to erode the ridge slightly. All models indicate that Gilma will generally slow down and turn west-northwestward in response to these steering changes, but there is unusually high spread in the guidance on the exact track the cyclone will take. The NHC track forecast follows the consensus aids, but confidence in the specifics of the forecast is lower than normal due to the high model spread. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 15.1N 116.0W 45 KT 50 MPH 12H 20/0000Z 15.3N 117.6W 50 KT 60 MPH 24H 20/1200Z 15.8N 119.3W 50 KT 60 MPH 36H 21/0000Z 16.5N 121.0W 50 KT 60 MPH 48H 21/1200Z 17.0N 122.6W 55 KT 65 MPH 60H 22/0000Z 17.5N 123.7W 65 KT 75 MPH 72H 22/1200Z 18.0N 124.7W 70 KT 80 MPH 96H 23/1200Z 19.0N 127.0W 70 KT 80 MPH 120H 24/1200Z 20.0N 129.0W 60 KT 70 MPH $$ Forecaster D. Zelinsky
Tropical Storm Gilma Forecast Discussion
19
Aug