519
WTNT44 KNHC 132038
TCDAT4
TROPICAL STORM SEAN DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192023
500 PM AST FRI OCT 13 2023
SEAN'S SATELLITE APPEARANCE CONTINUES TO DETERIORATE THIS AFTERNOON.
CONVECTION HAS WANED WITH WARMING CLOUD TOPS TO THE EAST OF THE
EXPOSED LOW-LEVEL CENTER. SEAN IS NOTICEABLY STRUGGLING WITH DRIER
AIR IMPACTING THE SYSTEM AND THE CONTINUED WESTERLY WIND SHEAR. ANY
CONVECTION THAT TRIES TO DEVELOP NEAR THE CENTER IS SHEARED OFF AND
DISSIPATES. SATELLITE INTENSITY ESTIMATES THIS AFTERNOON RANGE FROM
25 TO 40 KT. THE INITIAL INTENSITY IS HELD AT 35 KT FOR THIS
ADVISORY, BUT THIS COULD BE GENEROUS GIVEN THE WANING CONVECTION THE
LAST SEVERAL HOURS.
AS SEAN MOVES THROUGH THE DRIER AND MORE STABLE AIRMASS, FURTHER
WEAKENING IS ANTICIPATED. SIMULATED SATELLITE FROM THE ECMWF AND GFS
DEPICT THAT SEAN MAY HAVE OCCASIONAL BURST OF CONVECTION THE NEXT
DAY OR SO, BUT WILL CONTINUE TO BECOME LESS ORGANIZED. THIS SHOULD
CAUSE SEAN TO BECOME A POST-TROPICAL REMNANT LOW THIS WEEKEND.
HOWEVER, RECENT TRENDS SUGGEST THIS COULD OCCUR AS EARLY AS
TOMORROW. THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY, NEAR THE CONSENSUS INTENSITY AIDS.
THE TROPICAL STORM HAS CONTINUED TO MOVE WEST-NORTHWESTWARD TODAY,
AROUND 290 AT 10 KT. A TURN NORTHWESTWARD HAS BEEN FORECAST TO OCCUR
TODAY, BUT THE CENTER HAS CONTINUED WEST-NORTHWESTWARD, WHICH HAS
RESULTED IN A WESTWARD SHIFT OF THE NHC FORECAST TRACK. THE FORECAST
STILL CALLS FOR THE NORTHWESTWARD MOTION TO BEGIN LATER THIS EVENING
AND CONTINUE OVER THE NEXT DAY OR SO. AS SEAN BECOMES A REMNANT LOW
AND FURTHER WEAKENS, THE SYSTEM WILL TURN MORE WEST-NORTHWESTWARD
AGAIN AND DISSIPATE INTO AN OPEN TROUGH IN A FEW DAYS.
FORECAST POSITIONS AND MAX WINDS
INIT 13/2100Z 14.9N 42.5W 35 KT 40 MPH
12H 14/0600Z 15.8N 43.6W 30 KT 35 MPH
24H 14/1800Z 16.9N 44.7W 30 KT 35 MPH
36H 15/0600Z 17.7N 45.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 15/1800Z 18.4N 47.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 16/0600Z 18.8N 48.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 16/1800Z...DISSIPATED
FORECASTER KELLY
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