638
WTNT44 KNHC 070843
TCDAT4
TROPICAL STORM DEXTER DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042025
500 AM AST THU AUG 07 2025
DEXTER IS ON THE EDGE OF BEING EXTRATROPICAL. AN EARLIER
SCATTEROMETER OVERPASS SHOWED WHAT IS LIKELY A WARM FRONT EXTENDING
FROM THE EAST INTO OR NEAR THE CENTER. IN ADDITION, A CLOUD BAND IN
THE SOUTHEASTERN SEMICIRCLE APPEARS TO BE A DEVELOPING COLD FRONT.
HOWEVER, A STRONG CONVECTIVE BURST IS CURRENTLY OCCURRING A LITTLE
EAST OF THE CENTER, AND BASED ON THIS DEXTER AS MAINTAINED AS A
TROPICAL STORM AT THIS TIME. SATELLITE INTENSITY ESTIMATES HAVE
CHANGED LITTLE SINCE THE LAST ADVISORY, SO THE INITIAL INTENSITY IS
HELD AT 45 KT.
DEXTER SHOULD COMPLETE EXTRATROPICAL TRANSITION DURING THE NEXT
6-12 H AS IT MERGES WITH A MID- TO UPPER-LEVEL TROUGH APPROACHING
FROM THE NORTHWEST. GLOBAL MODEL SHOW STRENGTHENING DUE TO
BAROCLINIC FORCING AS THIS HAPPENS, AND DEXTER IS FORECAST TO
BECOME A HURRICANE-FORCE EXTRATROPICAL LOW IN ABOUT 24 HOURS.
GRADUAL WEAKENING IS EXPECTED AFTER THAT TIME AS THE UPPER-LEVEL
TROUGH DAMPENS OUT. THE NHC INTENSITY FORECAST REMAINS ABOVE THE
GUIDANCE IN THE SHORT TERM, BUT IN LINE WITH THE BULK OF THE MODELS
FROM 48 TO 96 HOURS. THE CYCLONE IS FORECAST TO WEAKEN TO A TROUGH
BY 120 H.
THE INITIAL MOTION IS NOW 070/16. A NORTHEASTWARD MOTION IS EXPECTED
DURING THE NEXT DAY OR TWO AS DEXTER INTERACTS AND MERGES WITH THE
AFOREMENTIONED TROUGH. AFTER THAT TIME, A TURN BACK TO THE
EAST-NORTHEAST OR EAST IS LIKELY AS THE CYCLONE IS STEERED BY THE
MID-LATITUDE WESTERLY FLOW. THE GUIDANCE NUDGED SLIGHTLY NORTHWARD
BETWEEN 24-60 H, AND THE NEW TRACK FORECAST HAS A SIMILAR SMALL
NUDGE. IT IS OTHERWISE SIMILAR TO THE PREVIOUS FORECAST AND CLOSE TO
THE VARIOUS CONSENSUS MODELS.
FORECAST POSITIONS AND MAX WINDS
INIT 07/0900Z 40.6N 52.1W 45 KT 50 MPH
12H 07/1800Z 41.7N 49.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
24H 08/0600Z 43.4N 45.3W 65 KT 75 MPH...POST-TROP/EXTRATROP
36H 08/1800Z 44.8N 41.2W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 09/0600Z 45.7N 36.8W 50 KT 60 MPH...POST-TROP/EXTRATROP
60H 09/1800Z 46.3N 32.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 10/0600Z 46.7N 28.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 11/0600Z 47.6N 20.7W 30 KT 35 MPH...POST-TROP/EXTRATROP
120H 12/0600Z...DISSIPATED
FORECASTER BEVEN
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