Issued at 1100 AM EDT Thu Oct 23 2025
000 WTNT43 KNHC 231449 TCDAT3 Tropical Storm Melissa Discussion Number 9 NWS National Hurricane Center Miami FL AL132025 1100 AM EDT Thu Oct 23 2025 Melissa's structure has undergone a metamorphosis this morning. Convection developed up-shear of the system for the first time after the prior advisory, with some evidence of loose banding beginning to take shape. This structure could indicate that the westerly vertical wind shear that has been affecting the system the last couple of days is beginning to subside, and could allow the low and mid-level centers to become better aligned. For now though, the surface circulation remains rather broad and still tilted to the northeast with height. The peak 850 mb flight level winds from the ongoing Air Force Reserve reconnaissance mission have only been 40 to 45 kt. A blend of the lower aircraft data and higher satellite estimates results in the initial intensity being adjusted to 40 kt for this advisory. The center of the tropical storm may have reformed northward from last night, as the last several aircraft fixes indicates a very slow north-northwestward drift, estimated at 345/2 kt. As has been emphasized over the last few discussions, Melissa is likely to continue moving very slowly as it drifts northward towards a weakness in the mid-level ridging produced by an upper-level trough over the Bahamas. This trough is expected to lift out over the next 24-48 hours, allowing a narrow mid-level ridge to build back in from the west. In response, the track guidance shows Melissa turning westward between 48 to 96 h, but the ridge remains centered to the northwest, likely explaining why the forward motion is expected to remain quite slow. Compared to 24 h ago, the guidance is in better agreement on this westward turn, but how sharp this turn is, and how far northward Melissa makes it in the meantime still remains uncertain. A variety of model solutions show Melissa south of Jamaica (ECMWF), over Jamaica (GDMI), or north of Jamaica (HMON). The track forecast this cycle continues to split the difference between the HFIP Corrected Consensus Approach (HCCA) and GDMI solutions, and is shifted a bit north compared to the previous track forecast. The shear over Melissa has been gradually decreasing, now under 20 kt in the latest ECMWF-SHIPS guidance. This shear is expected to decrease further, remaining between 10-15 kt over the remainder of the forecast period. Other environmental favors are also very favorable, with 30-31 C sea-surface temperatures, and sufficient mid-level moisture. The main intensity challenge is predicting when Melissa becomes a more symmetric and vertical aligned tropical cyclone. Given the improved structure seen on satellite, it seems the time-table for this process to occur has moved up in the forecast period. Assuming Melissa can then establish an inner core in the next 48 hours, a period of rapid intensification also appears increasingly likely, sometime in the 2 to 3 day period. The latest NHC intensity forecast now makes Melissa a hurricane in 48 hours, a major hurricane in 72 h, and a peak intensity of 115 kt in 96 hours. The end intensity could be conservative if Melissa ends up further south of Jamaica with less land interaction, as suggested by the 00z ECMWF and HAFS guidance. Over this period, the tropical cyclone is expected to grow in size, and likely be a large and dangerous hurricane towards the end of the forecast period. Key Messages: 1. Melissa is expected to meander over the central Caribbean Sea for several days and become a major hurricane by late this weekend or early next week. Due to Melissa’s slow motion, the risk of a prolonged multi-day period of potentially damaging winds, heavy rainfall resulting in life-threatening flash flooding and numerous landslides, and coastal flooding continues to increase for Jamaica. Preparations to protect life and property should be rushed to completion, since strong winds and flooding rains could begin in Jamaica by Friday or Saturday. 2. Strong winds could also potentially last for a day or more over the Tiburon peninsula of Haiti. In addition, interests in Cuba and the rest of Haiti are urged to continue monitoring the latest forecasts for Melissa. 3. In addition to Jamaica, Melissa will produce heavy rainfall across portions of the southern Dominican Republic and southern Haiti through this weekend and continuing into next week. This rainfall will result in significant, life-threatening flash flooding and numerous landslides. FORECAST POSITIONS AND MAX WINDS INIT 23/1500Z 15.4N 74.9W 40 KT 45 MPH 12H 24/0000Z 15.9N 75.0W 45 KT 50 MPH 24H 24/1200Z 16.3N 74.9W 50 KT 60 MPH 36H 25/0000Z 16.7N 74.9W 60 KT 70 MPH 48H 25/1200Z 17.1N 75.2W 75 KT 85 MPH 60H 26/0000Z 17.3N 75.8W 90 KT 105 MPH 72H 26/1200Z 17.4N 76.4W 105 KT 120 MPH 96H 27/1200Z 17.4N 77.7W 115 KT 130 MPH 120H 28/1200Z 17.7N 78.4W 115 KT 130 MPH $$ Forecaster Papin
NHC Atlantic
