Issued at 500 PM EDT Thu Oct 23 2025
000 WTNT43 KNHC 232059 TCDAT3 Tropical Storm Melissa Discussion Number 10 NWS National Hurricane Center Miami FL AL132025 500 PM EDT Thu Oct 23 2025 Like the past couple of days, Melissa's structure has degraded once again this afternoon, with the low-level circulation yet again becoming partially exposed on the west side of the deepest convection. This structure is consistent with a tropical cyclone that continues to exhibit significant tilt with height in the downshear direction. A scatterometer pass received after the prior advisory also indicated the center itself remains quite broad with a continued asymmetric wind field and large radius of maximum wind. The initial intensity is being held at 40 kt this advisory, without a substantial change in the subjective or objective intensity aids since the last recon plane left the storm. A NOAA-P3 recon mission will sample the system this evening providing updated detail on the structure and intensity of the storm. Melissa continues to move very slowly, with the initial motion a very slow north-northwest drift at 345/2 kt. The tropical storm's very slow motion over the last day or so is related to it being caught between two mid-level ridges, one located to its southeast over the Lesser Antilles providing northeast steering, and another mid-level ridge building in northwest from Mexico providing southwest steering. Their combined influence is roughly canceling Melissa's overall steering, with a lot of track influences the last couple of nights related to center reformations to the east and north. Interestingly, much of the hurricane-regional model guidance suggests another reformation could occur tonight, and the track guidance envelope has a distinct bend to the northeast in the 12 to 24 hour forecast points. Given the large convective burst ongoing just east of the current broad center, it is feasible it may nudge the short-term track east of due north. After the next day or so, the mid-level ridge currently over Mexico is expected to expand poleward of the storm, and is expected to help turn Melissa to the west. How far north Melissa gets before it turns to the west continues to remain uncertain. One notable change from this morning is that the 12z Google DeepMind ensemble mean (GDMI), which was previously on the northeast side of the track guidance, abruptly shifted to the southwest side of the envelope, now very close to the latest 12z ECWMF forecast. In contrast, both the 12z HAFS-A/B regional hurricane models shifted their tracks further north and east, related to an overnight center reformation. All these shuffling guidance tracks highlight the uncertainty of the overall track forecast, and the latest NHC track was only nudged slightly southward from this morning, blending the reliable HCCA and GDMI aids. This forecast track takes Melissa just south of Jamaica in 60-96 hours, though it is worth noting there are guidance aids that move it near or over Jamaica earlier in the forecast than shown here. Melissa's broad and asymmetric structure argues against much short-term intensification, though the shear that had been plaguing the system is soon expected to decrease. It will likely take at least 24 hours for the storm's tilted structure to become better aligned to take advantage of the other favorable environmental factors (very warm sea-surface temperatures, sufficently moist mid-levels). Regardless, the intensity guidance is insistent on Melissa undergoing a period of rapid intensification in the forecast period, and all 50 members of the Google DeepMind ensemble show the system becoming a major hurricane or stronger. The NHC intensity forecast will follow suit, showing rapid intensification from 36 to 72 h, intensifying Melissa from a tropical storm to a category 4 hurricane in this time period. Remarkably, this is still lower than some of the hurricane-regional models, and is in best agreement with the GDMI intensity forecast, which have plenty of members stronger this the current NHC peak intensity of 125 kt. Over the forecast period, the tropical cyclone is expected to grow in size significantly, and it will likely be a large and dangerous hurricane towards the end of the forecast period. Key Messages: 1. Jamaica: 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 storm surge 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. Haiti: Heavy rainfall will result in catastrophic flash flooding and landslides across southwestern Haiti by this weekend into early next week. Extensive damage to roads and buildings is expected, potentially isolating communities for an extended period of time. This is a life-threatening situation and immediate preparations to protect life and property should be taken. Strong winds could also potentially last for a day or more over the Tiburon peninsula of Haiti. 3. Remainder of Hispaniola and Eastern Cuba: Heavy rainfall could also produce significant, life-threatening flash flooding and numerous landslides in southern Dominican Republic. Interests in Cuba should monitor the progress of Melissa since the risk of heavy rainfall, damaging winds, and storm surge appears to be increasing. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 15.6N 75.5W 40 KT 45 MPH 12H 24/0600Z 15.8N 75.2W 45 KT 50 MPH 24H 24/1800Z 16.0N 75.0W 50 KT 60 MPH 36H 25/0600Z 16.5N 75.1W 60 KT 70 MPH 48H 25/1800Z 16.8N 75.4W 80 KT 90 MPH 60H 26/0600Z 17.1N 76.0W 100 KT 115 MPH 72H 26/1800Z 17.1N 76.7W 115 KT 130 MPH 96H 27/1800Z 17.1N 77.8W 125 KT 145 MPH 120H 28/1800Z 18.0N 78.4W 125 KT 145 MPH $$ Forecaster Papin