529
WTNT41 KNHC 210245
TCDAT1
TROPICAL STORM OSCAR DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162024
1100 PM EDT SUN OCT 20 2024
OSCAR MADE LANDFALL AROUND 2150 UTC AS A 70-KT HURRICANE NEAR THE
CITY OF BARACOA IN THE GUANTANAMO PROVINCE OF EASTERN CUBA. RADAR
DATA FROM GUANTANAMO BAY SHOWS OSCAR HAS CONTINUED TO MOVE SLOWLY
OVER EASTERN CUBA TONIGHT, WITH HEAVY RAINFALL SPREADING ACROSS THE
REGION. OSCAR'S SLOW MOTION WILL ENHANCE THE POTENTIAL FOR HEAVY
RAINFALL, LIFE-THREATENING FLASH FLOODING, AND MUDSLIDES ACROSS
EASTERN CUBA, PARTICULARLY NEAR HIGHER TERRAIN. THERE HAS BEEN
NOTABLE DEGRADATION OF OSCAR'S INNER CORE STRUCTURE IN RECENT RADAR
AND SATELLITE IMAGES, WHICH SUGGESTS WEAKENING IS OCCURRING DUE TO
ONGOING LAND INTERACTION. THE INITIAL INTENSITY IS LOWERED TO 60 KT
FOR THIS ADVISORY.
OSCAR WOBBLED SLIGHTLY SOUTHWARD ON ITS FINAL APPROACH TO CUBA, BUT
RECENT RADAR DATA SUGGEST THE SYSTEM HAS RESUMED A SLOW
WEST-SOUTHWESTWARD TO WESTWARD MOTION. OSCAR SHOULD REMAIN OVER
EASTERN CUBA OR VERY NEAR THE COAST DURING THE NEXT 12-24 H.
THEREAFTER, THE FLOW AHEAD OF A DIGGING SHORTWAVE TROUGH OVER THE
SOUTHWESTERN ATLANTIC IS FORECAST TO CAPTURE OSCAR, WHICH SHOULD
RESULT IN A NORTHEASTWARD ACCELERATION THROUGH MIDWEEK. THE TRACK
GUIDANCE TRENDED FASTER THIS CYCLE, PARTICULARLY THE ECMWF (WHICH
HAS HANDLED OSCAR WELL) AND EVEN THE GFS WITH A SHALLOWER VORTEX
DEPICTION. THE NHC TRACK FORECAST ONCE AGAIN SHOWS A FASTER FORWARD
SPEED BETWEEN 36-72 H, GENERALLY BETWEEN THE HCCA/TVCN CONSENSUS
AIDS AND THE GFS/ECMWF (GFEX).
WEAKENING IS EXPECTED TO CONTINUE AS THE INNER CORE STRUCTURE OF
OSCAR IS DISRUPTED BY THE MOUNTAINOUS TERRAIN OF EASTERN CUBA. THE
EXTENT OF THE WEAKENING THAT OCCURS, AND WHETHER OSCAR REMAINS A
TROPICAL CYCLONE (TC) ONCE IT EMERGES OFF THE NORTHERN COAST OF
CUBA, IS STILL SOMEWHAT UNCERTAIN. THE ECMWF HAS BEEN THE
BEST-PERFORMING GUIDANCE FOR OSCAR AND SHOWS IT REMAINING A TC,
WHILE OTHER MODELS INCLUDING THE GFS SUGGEST MORE SIGNIFICANT
WEAKENING AND POSSIBLE DEGENERATION TO A SURFACE TROUGH. EVEN IF
OSCAR SURVIVES, THE ENVIRONMENTAL CONDITIONS OVER THE SOUTHWESTERN
ATLANTIC ARE EXPECTED TO BECOME MORE HOSTILE, WITH STRONGER VERTICAL
WIND SHEAR AND A DRIER SURROUNDING AIRMASS LIKELY TO INHIBIT MUCH
REDEVELOPMENT. THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
ONE, BUT SHOWS POST-TROPICAL STATUS AT 72 H GIVEN THE SHEAR. IF
OSCAR SURVIVES THAT LONG, IT SHOULD BECOME ABSORBED BY A LARGER,
NON-TROPICAL LOW PRESSURE SYSTEM OVER THE WESTERN ATLANTIC BY 96 H.
KEY MESSAGES:
1. 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.
2. TROPICAL STORM CONDITIONS ARE EXPECTED TO CONTINUE OVERNIGHT
ACROSS PORTIONS OF EASTERN CUBA, WHERE A TROPICAL STORM WARNING IS
IN EFFECT.
FORECAST POSITIONS AND MAX WINDS
INIT 21/0300Z 20.3N 74.6W 60 KT 70 MPH
12H 21/1200Z 20.4N 75.0W 50 KT 60 MPH...INLAND
24H 22/0000Z 20.9N 75.3W 40 KT 45 MPH...OVER WATER
36H 22/1200Z 21.9N 74.9W 40 KT 45 MPH
48H 23/0000Z 23.4N 73.7W 40 KT 45 MPH
60H 23/1200Z 25.1N 72.1W 40 KT 45 MPH
72H 24/0000Z 27.3N 70.2W 35 KT 40 MPH...POST-TROPICAL
96H 25/0000Z...DISSIPATED
FORECASTER REINHART
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