018
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
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