341
WTNT44 KNHC 152032
TCDAT4
TROPICAL DEPRESSION SEAN DISCUSSION NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192023
500 PM AST SUN OCT 15 2023
SEAN CONTINUES TO PRODUCE BURSTS OF CONVECTION THIS AFTERNOON TO
THE SOUTH OF THE LOW-LEVEL CENTER. AN EARLIER SCATTEROMETER PASS
DEPICTED THAT WINDS HAD WEAKENED TO 20-25 KT. DVORAK SATELLITE
INTENSITY ESTIMATES CONTINUE TO DECREASE AS WELL WITH A T1.0/25 KT
FROM TAFB THIS CYCLE. USING THE PREVIOUS SCATTEROMETER DATA AND THE
CURRENT INTENSITY ESTIMATE, THE INITIAL INTENSITY REMAINS 25 KT FOR
THIS ADVISORY.
SEAN CONTINUES TO BE RESILIENT AND PRODUCE CONVECTIVE BURSTS FROM
TIME TO TIME. THE DRY MID-LEVEL AIR HAS NOT BEEN ABLE TO FULLY
SUPPRESS THE CONVECTION, EVEN THOUGH THE CONVECTION IS BECOMING LESS
ORGANIZED. THE CONVECTIVE PATTERN COULD BECOME UNORGANIZED ENOUGH TO
NO LONGER DECLARE SEAN A TROPICAL CYCLONE SOON. MODEL SIMULATED
SATELLITE IMAGERY CONTINUES TO INSIST THAT THE SYSTEM WILL GRADUALLY
DECAY AND BECOME DEVOID OF CONVECTION. THE NHC FORECAST IS SIMILAR
TO THE PREVIOUS, WITH SEAN FORECAST TO BECOME A POST-TROPICAL
REMNANT LOW TONIGHT, ALTHOUGH THE SYSTEM MAY HOLD ON UNTIL THE
CIRCULATION OPENS UP INTO A TROUGH IN ABOUT 36 HOURS.
THE DEPRESSION IS MOVING WEST-NORTHWESTWARD WITH AN ESTIMATED
MOTION OF 285/10 KT. AS THE SYSTEM WEAKENS AND BECOMES VERTICALLY
SHALLOW, A TURN MORE WESTWARD IS FORECAST WITHIN THE LOW-LEVEL
STEERING FLOW. THE NHC TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND
IS NEAR THE CORRECTED AND SIMPLE CONSENSUS AIDS.
FORECAST POSITIONS AND MAX WINDS
INIT 15/2100Z 18.0N 48.2W 25 KT 30 MPH
12H 16/0600Z 18.2N 49.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 16/1800Z 18.4N 52.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 17/0600Z...DISSIPATED
FORECASTER KELLY
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