Issued at 500 PM HST Tue Jul 28 2026
000 WTPZ42 KNHC 290233 TCDEP2 Hurricane Genevieve Discussion Number 20 NWS National Hurricane Center Miami FL EP072026 500 PM HST Tue Jul 28 2026 Genevieve's satellite presentation has continued to oscillate this afternoon and evening, with deep cold convection wrapping around a cloud-filled eye with occasional lightning. A GPM microwave pass showed that the western eyewall had started to erode. Over the last few hours, there have been occasional breaks within the inner core, but the inner core has been resilient and has continued to wrap deep convection. Objective intensity estimates from UW-CIMSS remain around 105–118 kt, which prompted the special advisory a few hours ago. Using these estimates, the initial intensity is held at 115 kt for this advisory. The hurricane will remain in a marginal environment over the next 24 hours, characterized by low-to-moderate vertical wind shear, sea surface temperatures near 27–28C, and mid-level relative humidity values in the 50 to 60 percent range. Changes in convective organization and inner core dynamics will allow for short-term intensity fluctuations over the next day or so. Gradual weakening is forecast through 24 hours, followed by a faster rate of decay once the system crosses the 26C isotherm in 24–36 hours. As the cyclone traverses cooler waters, decreasing mid-level relative humidity will further suppress deep convection. The official NHC intensity forecast lies near the upper end of the guidance suite in the short term, reflecting recent intensity adjustments, and aligns closely with the consensus aids from 48 hours through the end of the forecast period. The timing of post-tropical transition has been moved up to Day 4, consistent with model simulated satellite imagery from the latest GFS and ECMWF. Genevieve is moving west-northwestward at an estimated motion of 290/8 kt along the southwestern periphery of a ridge centered to the northwest of the system. A slightly faster forward speed is anticipated during the next few days as the ridge expands westward. The NHC track forecast was shifted slightly to the left, and lies closest to the HCCA corrected consensus aid. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 18.3N 117.6W 115 KT 130 MPH 12H 29/1200Z 18.6N 118.9W 115 KT 130 MPH 24H 30/0000Z 19.3N 120.8W 105 KT 120 MPH 36H 30/1200Z 20.0N 123.2W 90 KT 105 MPH 48H 31/0000Z 20.7N 125.6W 75 KT 85 MPH 60H 31/1200Z 21.5N 128.0W 60 KT 70 MPH 72H 01/0000Z 22.2N 130.7W 50 KT 60 MPH 96H 02/0000Z 23.7N 136.4W 40 KT 45 MPH...POST-TROPICAL 120H 03/0000Z 25.5N 141.7W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Kelly
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