694
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



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