Issued at 1100 AM AST Mon Aug 04 2025
ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM Tropical Storm Dexter Discussion Number 3 NWS National Hurricane Center Miami FL AL042025 1100 AM AST Mon Aug 04 2025 Several bursts of deep convection have formed with Dexter this morning, but the latest visible satellite images suggest the center is on the far western edge of the cirrus canopy, partially exposed. The intensity estimates from SAB and TAFB remain unchanged for 12 UTC, and objective estimates from UW-CIMSS (ADT, DPRINT, DMINT) support maintaining a current intensity of 40 kt this advisory. Dexter continues to move northeastward, a bit faster than earlier at 050/12 kt. This general motion is forecast to continue for the next couple of days with a brief slowdown as the storm is steered by a narrow subtropical ridge located to its southeast. In around 60 h, a shortwave trough dropping southward from Atlantic Canada may try to phase with Dexter. However, the global and ensemble model guidance is split if their interaction will be favorable, causing the storm to accelerate northeastward, or unfavorable, leaving Dexter behind as a convection-less remnant low. For this cycle, the track guidance has shifted a bit faster to the northeast, and the NHC track has also been shifted faster, but generally along the same track as the previous advisory. It is worth noting that the Google Deep Mind ensemble mean (GDMI) is a significant fast outlier, and it will be interesting to see if the overall model guidance continues to trend faster with Dexter's motion. Intensity-wise, Dexter is likely to face an increasingly hostile environment, with westerly vertical wind shear increasing above 30 kt in about 24 h. Thus, only a little additional strengthening is shown in the forecast for today, then capping the intensity at 45 kt through the rest of this week. However, since the cyclone will remain over the warm Gulf Stream waters until it passes poleward of 40N, it will likely continue to produce periodic bursts of deep convection, helping to maintain its intensity in the face of the unfavorable shear. After 60 h, the guidance remains split on whether or not Dexter will become a remnant low, or phase with the upper-level trough nearby, becoming a stronger extratropical low. While the latest intensity forecast shows the latter solution panning out, as mentioned previously, Dexter's final structure remains quite uncertain near the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 35.2N 67.4W 40 KT 45 MPH 12H 05/0000Z 36.5N 65.4W 45 KT 50 MPH 24H 05/1200Z 37.6N 63.4W 45 KT 50 MPH 36H 06/0000Z 38.5N 61.6W 45 KT 50 MPH 48H 06/1200Z 39.4N 59.1W 45 KT 50 MPH 60H 07/0000Z 40.1N 55.4W 45 KT 50 MPH 72H 07/1200Z 41.0N 50.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 08/1200Z 43.9N 43.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 09/1200Z 46.5N 36.1W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin NNNN