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WTNT41 KNHC 202046
TCDAT1
HURRICANE OSCAR DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162024
500 PM EDT SUN OCT 20 2024
OSCAR IS VERY CLOSE TO MAKING LANDFALL THIS AFTERNOON ALONG THE
NORTHERN COAST OF EASTERN CUBA. SINCE THE FINAL OBSERVATIONS FROM
THE MORNING AIR FORCE RECONNAISSANCE MISSION, THE HURRICANE'S
STRUCTURE ON SATELLITE IMAGERY AND RADAR OUT OF GUANTANAMO BAY HAS
NOT CHANGED APPRECIABLY, WITH ROTATING COLD CONVECTIVE BANDS NOTED
ON 1 MINUTE GOES-16 IMAGERY, AND THE EYEWALL ON RADAR COMING AND
GOING, OCCASIONALLY OPEN ON THE WESTERN SIDE. SUBJECTIVE AND
OBJECTIVE INTENSITY ESTIMATES HAVE NOT CHANGED MUCH FROM WHEN THE
PLANE WAS IN THE HURRICANE THIS MORNING, SO THE INITIAL INTENSITY
WILL REMAIN AT 70 KT THIS ADVISORY.
OSCAR HAS CONTINUED A WEST-SOUTHWESTWARD MOTION, BUT IS SLOWING DOWN
AS IT NEARS THE CUBAN COAST, ESTIMATED NOW AT 250/5 KT. THE
STRONGEST MID-LEVEL RIDGING IS NOW ORIENTED TO THE NORTHWEST OF
OSCAR AND IS HELPING TO STEER THE SMALL HURRICANE WEST-SOUTHWESTWARD
INTO CUBA. HOWEVER, BY TOMORROW A DIGGING SHORTWAVE TROUGH ON THE
EASTERN SIDE OF A BROADER TROUGH ACROSS THE WESTERN ATLANTIC SHOULD
FURTHER ERODE THE STEERING FLOW NORTH OF OSCAR, WITH MUCH OF THE
TRACK GUIDANCE SHOWING THE SYSTEM EXECUTING A SLOW BUT SHARP TURN
NORTHWARD ON MONDAY, ULTIMATELY CAUSING THE TROPICAL CYCLONE TO
EMERGE BACK OUT OVER OPEN WATERS IN 24-36 H. HOW FAST OSCAR THEN
ACCELERATES TO THE NORTHEAST COULD BE RELATED TO HOW VERTICALLY DEEP
THE CIRCULATION IS BY THE EARLY PART OF THIS WEEK, WITH THE GFS
SHOWING A SHALLOW OSCAR DRIFTING SLOWLY OVER THE CENTRAL BAHAMAS,
WHILE THE ECMWF KEEPS A STRONGER OSCAR ACCELERATING NORTHEASTWARD.
THE NHC TRACK FORECAST IS A LITTLE FASTER THAN THE PREVIOUS
ADVISORY, SLIGHTLY FAVORING THE ECMWF FORECAST SOLUTION OVER THE GFS
GIVEN ITS BETTER PERFORMANCE WITH THIS SMALL TROPICAL CYCLONE, AND
LIES NOT FAR OFF THE TVCA AND HCCA CONSENSUS AIDS.
THE SMALL INNER CORE OF OSCAR IS LIKELY TO BE SEVERELY DISRUPTED BY
THE HIGHER TERRAIN OF EASTERN CUBA AFTER IT MAKES LANDFALL, AND
WEAKENING AFTER IT MOVES ASHORE WILL LIKELY BE QUICK. SOME OF THE
GUIDANCE, ESPECIALLY THE GFS, SUGGESTS THAT OSCAR COULD WEAKEN MORE
THAN SHOWN HERE IN THE LATEST NHC INTENSITY FORECAST. ONCE OSCAR
RE-EMERGES OVER THE ATLANTIC OCEAN, THE FORECAST ENVIRONMENT IS NOT
VERY FAVORABLE FOR REINTENSIFICATION, WITH WESTERLY SHEAR INCREASING
ABOVE 30 KT IN 36 H AND PLENTY OF VERY DRY AIR WAITING TO BE
IMPORTED INTO THE CYCLONE'S CORE. THE NHC FORECAST DOES NOT SHOW ANY
INTENSIFICATION AFTER IT EMERGES BACK OFFSHORE, AND MOST OF THE
GUIDANCE SHOWS THE SMALL CYCLONE BEING ABSORBED BY THE MUCH LARGER
BAROCLINIC TROUGH SOMETIME THIS WEEK, THOUGH THE TIMING VARIES AMONG
THE GLOBAL AND HURRICANE-REGIONAL MODEL GUIDANCE.
KEY MESSAGES:
1. A HURRICANE WARNING IS IN EFFECT FOR A PORTION OF THE NORTHERN
COAST OF EASTERN CUBA WHERE OSCAR IS EXPECTED TO MAKE LANDFALL
SHORTLY.
2. OSCAR IS EXPECTED TO PRODUCE A DANGEROUS STORM SURGE ON PORTIONS
OF THE NORTH SHORE OF EASTERN CUBA THIS AFTERNOON AND EVENING.
3. THROUGH MIDWEEK, HEAVY RAINFALL FROM OSCAR WILL LEAD TO AREAS OF
SIGNIFICANT, POTENTIALLY LIFE-THREATENING FLASH FLOODING ALONG WITH
MUDSLIDES ACROSS PORTIONS OF EASTERN CUBA, ESPECIALLY WITHIN THE
SIERRA MAESTRA. IN ADDITION, LOCALIZED FLASH FLOODING WILL BE
POSSIBLE ACROSS THE SOUTHEASTERN BAHAMAS.
FORECAST POSITIONS AND MAX WINDS
INIT 20/2100Z 20.5N 74.3W 70 KT 80 MPH
12H 21/0600Z 20.4N 75.0W 55 KT 65 MPH...INLAND
24H 21/1800Z 20.6N 75.4W 40 KT 45 MPH...INLAND
36H 22/0600Z 21.6N 75.5W 40 KT 45 MPH...OVER WATER
48H 22/1800Z 22.7N 75.0W 40 KT 45 MPH
60H 23/0600Z 23.7N 73.9W 40 KT 45 MPH
72H 23/1800Z 25.2N 72.0W 35 KT 40 MPH
96H 24/1800Z...DISSIPATED
FORECASTER PAPIN
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