985 WTPZ44 KNHC 041448 TCDEP4 Hurricane Bonnie Discussion Number 28 NWS National Hurricane Center Miami FL EP042022 1000 AM CDT Mon Jul 04 2022 Bonnie's satellite presentation has improved this morning with a ragged eye becoming more apparent in both infrared and visible satellite imagery. An earlier AMSR2 microwave overpass that arrived after the release of the previous advisory, and more recent SSMIS imagery revealed a fairly well-defined low- to mid-level eye feature. Subjective Dvorak estimates from both TAFB and SAB are T4.5 or 77 kt. Objective estimates from UW/CIMSS are lagging a bit, but recent raw T-numbers have increased as the eye has become better defined. The advisory intensity is set at 80 kt, near the higher end of the estimates due to the continued improvement in structure. Bonnie's intensity forecast is a bit tricky this morning as expected subtle changes in shear throughout the forecast period could have larger-than-normal implications on the forecast. In the very near term, some additional strengthening is likely while Bonnie remains within an area of moderate northeasterly shear and otherwise favorable environmental conditions. The NHC wind speed forecast is near the high end of the guidance during the first 12-24 hours given the recent upward trend in organization. The shear is forecast to increase on Tuesday, which the guidance suggests will cause Bonnie's intensity to plateau or perhaps fluctuate over the next 2-3 days. By 72 hours, global models now indicate that the shear will decrease while the system is still over marginally warm water. As a result, the NHC forecast keeps Bonnie's intensity slightly higher through 96 h than the previous advisory. Shortly after that time, rapid weakening is likely to begin as the cyclone moves over waters less than 26C and into a less favorable thermodynamic environment. Bonnie is moving briskly westward to west-northwestward with a longer term motion of 285/16 kt. The track forecast reasoning has not changed over the past day or so. Bonnie should continue to move generally west-northwestward with some reduction in forward speed while it is steered by a large mid-level to the north. This motion will take Bonnie roughly parallel to but well offshore the coasts of southern and southwestern Mexico during the next day or two. The latest NHC track forecast is again an update of the previous advisory, and it remains close to the TVCE multi-model consensus aid. The forecast keeps tropical-storm-force winds associated with Bonnie offshore the coast of southern and southwestern Mexico, but coastal locations can still expect rough surf and the potential for rip currents today and Tuesday as Bonnie passes offshore. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 13.7N 99.0W 80 KT 90 MPH 12H 05/0000Z 14.4N 101.2W 90 KT 105 MPH 24H 05/1200Z 15.1N 104.0W 90 KT 105 MPH 36H 06/0000Z 15.6N 106.4W 90 KT 105 MPH 48H 06/1200Z 16.0N 108.6W 90 KT 105 MPH 60H 07/0000Z 16.2N 110.7W 90 KT 105 MPH 72H 07/1200Z 16.4N 112.8W 90 KT 105 MPH 96H 08/1200Z 17.6N 117.8W 85 KT 100 MPH 120H 09/1200Z 19.1N 124.0W 65 KT 75 MPH $$ Forecaster Brown