477
WTPZ42 KNHC 290233
TCDEP2
HURRICANE GENEVIEVE DISCUSSION NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072026
500 PM HST TUE JUL 28 2026
GENEVIEVE'S SATELLITE PRESENTATION HAS CONTINUED TO OSCILLATE THIS
AFTERNOON AND EVENING, WITH DEEP COLD CONVECTION WRAPPING AROUND A
CLOUD-FILLED EYE WITH OCCASIONAL LIGHTNING. A GPM MICROWAVE PASS
SHOWED THAT THE WESTERN EYEWALL HAD STARTED TO ERODE. OVER THE LAST
FEW HOURS, THERE HAVE BEEN OCCASIONAL BREAKS WITHIN THE INNER CORE,
BUT THE INNER CORE HAS BEEN RESILIENT AND HAS CONTINUED TO WRAP DEEP
CONVECTION. OBJECTIVE INTENSITY ESTIMATES FROM UW-CIMSS REMAIN
AROUND 105–118 KT, WHICH PROMPTED THE SPECIAL ADVISORY A FEW HOURS
AGO. USING THESE ESTIMATES, THE INITIAL INTENSITY IS HELD AT 115 KT
FOR THIS ADVISORY.
THE HURRICANE WILL REMAIN IN A MARGINAL ENVIRONMENT OVER THE NEXT 24
HOURS, CHARACTERIZED BY LOW-TO-MODERATE VERTICAL WIND SHEAR, SEA
SURFACE TEMPERATURES NEAR 27–28C, AND MID-LEVEL RELATIVE HUMIDITY
VALUES IN THE 50 TO 60 PERCENT RANGE. CHANGES IN CONVECTIVE
ORGANIZATION AND INNER CORE DYNAMICS WILL ALLOW FOR SHORT-TERM
INTENSITY FLUCTUATIONS OVER THE NEXT DAY OR SO. GRADUAL WEAKENING IS
FORECAST THROUGH 24 HOURS, FOLLOWED BY A FASTER RATE OF DECAY ONCE
THE SYSTEM CROSSES THE 26C ISOTHERM IN 24–36 HOURS. AS THE CYCLONE
TRAVERSES COOLER WATERS, DECREASING MID-LEVEL RELATIVE HUMIDITY WILL
FURTHER SUPPRESS DEEP CONVECTION. THE OFFICIAL NHC INTENSITY
FORECAST LIES NEAR THE UPPER END OF THE GUIDANCE SUITE IN THE SHORT
TERM, REFLECTING RECENT INTENSITY ADJUSTMENTS, AND ALIGNS CLOSELY
WITH THE CONSENSUS AIDS FROM 48 HOURS THROUGH THE END OF THE
FORECAST PERIOD. THE TIMING OF POST-TROPICAL TRANSITION HAS BEEN
MOVED UP TO DAY 4, CONSISTENT WITH MODEL SIMULATED SATELLITE IMAGERY
FROM THE LATEST GFS AND ECMWF.
GENEVIEVE IS MOVING WEST-NORTHWESTWARD AT AN ESTIMATED MOTION OF
290/8 KT ALONG THE SOUTHWESTERN PERIPHERY OF A RIDGE CENTERED TO THE
NORTHWEST OF THE SYSTEM. A SLIGHTLY FASTER FORWARD SPEED IS
ANTICIPATED DURING THE NEXT FEW DAYS AS THE RIDGE EXPANDS WESTWARD.
THE NHC TRACK FORECAST WAS SHIFTED SLIGHTLY TO THE LEFT, AND LIES
CLOSEST TO THE HCCA CORRECTED CONSENSUS AID.
FORECAST POSITIONS AND MAX WINDS
INIT 29/0300Z 18.3N 117.6W 115 KT 130 MPH
12H 29/1200Z 18.6N 118.9W 115 KT 130 MPH
24H 30/0000Z 19.3N 120.8W 105 KT 120 MPH
36H 30/1200Z 20.0N 123.2W 90 KT 105 MPH
48H 31/0000Z 20.7N 125.6W 75 KT 85 MPH
60H 31/1200Z 21.5N 128.0W 60 KT 70 MPH
72H 01/0000Z 22.2N 130.7W 50 KT 60 MPH
96H 02/0000Z 23.7N 136.4W 40 KT 45 MPH...POST-TROPICAL
120H 03/0000Z 25.5N 141.7W 35 KT 40 MPH...POST-TROPICAL
FORECASTER KELLY
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