261
WTNT44 KNHC 140836
TCDAT4
TROPICAL STORM SEAN DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192023
500 AM AST SAT OCT 14 2023
SEAN HAS BEEN PRODUCING BURSTS OF DEEP CONVECTION OVERNIGHT THAT
HAVE OBSCURED THE CENTER OF THE CYCLONE. THE BURSTS DO NOT APPEAR
TO HAVE MUCH ORGANIZATION, AND THE LATEST SUBJECTIVE AND OBJECTIVE
SATELLITE INTENSITY ESTIMATES RANGE FROM ABOUT 25 TO 40 KT. THE
INITIAL INTENSITY FOR THIS ADVISORY IS KEPT AT 35 KT, WHICH IS IN
AGREEMENT WITH THE LATEST TAFB DVORAK CI NUMBER OF T2.5 (35 KT).
HOWEVER, THIS COULD BE GENEROUS.
SEAN IS MOVING WEST-NORTHWESTWARD OR 300 DEGREES AT ABOUT 7 KT.
THE CYCLONE SHOULD TURN NORTHWESTWARD TODAY AROUND THE SOUTHWESTERN
PERIPHERY OF A NARROW RIDGE OVER THE EASTERN-CENTRAL ATLANTIC. A
TURN BACK TOWARD THE WEST-NORTHWEST IS ANTICIPATED ON SUNDAY WHEN
SEAN WEAKENS AND BECOMES MORE VERTICALLY SHALLOW. THERE IS A FAIR
AMOUNT OF SPREAD IN THE TRACK GUIDANCE THAT IS RELATED TO HOW
QUICKLY SEAN WEAKENS. THE ECMWF WHICH IS THE WEAKER OF THE
DYNAMICAL MODELS TAKES THE CYCLONE ON A MORE SOUTHERLY TRACK. THE
NHC FORECAST IS A LITTLE SOUTH OF THE PREVIOUS ADVISORY, ESPECIALLY
AT 48 AND 60 HOURS, AND LIES NEAR THE MIDDLE OF THE GUIDANCE
ENVELOPE.
SEAN IS FORECAST TO ENCOUNTER AN INCREASINGLY DRY MID-LEVEL
ENVIRONMENT DURING THE NEXT COUPLE OF DAYS, WHICH SHOULD CAUSE
GRADUAL WEAKENING DURING THAT TIME. THE GLOBAL MODEL GUIDANCE
INDICATES THAT SEAN WILL STRUGGLE TO PRODUCE DEEP CONVECTION BY
LATER TODAY AND SUNDAY, AND IT SEEMS LIKELY THAT THE SYSTEM WILL
DEGENERATE INTO A REMNANT LOW BY 36 HOURS, IF NOT SOONER. THE
CIRCULATION IS EXPECTED TO OPEN UP INTO A TROUGH IN 60 TO 72 HOURS,
AND DISSIPATION IS INDICATED IN THE OFFICIAL FORECAST BY DAY 3.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0900Z 15.4N 43.4W 35 KT 40 MPH
12H 14/1800Z 16.1N 44.2W 30 KT 35 MPH
24H 15/0600Z 16.9N 45.4W 30 KT 35 MPH
36H 15/1800Z 17.5N 47.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 16/0600Z 17.9N 48.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 16/1800Z 18.1N 50.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 17/0600Z...DISSIPATED
FORECASTER BROWN
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