000
WTNT44 KNHC 262059
TCDAT4
 
TROPICAL STORM DEBBY DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
500 PM EDT TUE JUN 26 2012
 
AN AIR FORCE MISSION THAT ENDED EARLY THIS AFTERNOON MEASURED
BIAS-CORRECTED SFMR WINDS JUST BELOW TROPICAL STORM STRENGTH. BASED
ON THOSE DATA...IT IS ASSUMED THAT THERE ARE STILL A FEW SPOTS OF
TROPICAL-STORM-FORCE WINDS REMAINING IN BANDS TO THE SOUTHEAST OF
THE CENTER. IN THE FACE OF STRONG WESTERLY VERTICAL WIND
SHEAR...DEBBY IS GENERATING ONLY LIMITED DEEP CONVECTION TO THE
NORTHEAST OF THE CENTER OVER NORTHERN FLORIDA...AND HAS LESS THAN A
FULLY TROPICAL APPEARANCE. THE CYCLONE IS ALSO BEING OVERTAKEN BY A
LARGE REGION OF DRY AIR OVER THE SOUTHERN UNITED STATES AND GULF OF
MEXICO. THE PASSAGE OF DEBBY OVER LAND...IN ADDITION TO THE
NEGATIVE FACTORS CITED ABOVE...WILL LIKELY CAUSE DEBBY TO WEAKEN TO
A DEPRESSION WITHIN 12 HOURS. AFTER THE CENTER EMERGES OVER THE
WESTERN ATLANTIC...SUBSTANTIALLY LOWER SHEAR AND WARMER WATERS
FAVOR SOME RE-INTENSIFICATION OF THE CYCLONE LATER IN THE FORECAST
PERIOD. THE NEW NHC FORECAST IS CLOSE TO THE SHIPS/LGEM GUIDANCE
AND IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
AS ADVERTISED BY DYNAMICAL MODELS...DEBBY IS MOVING FASTER TOWARD
THE EAST-NORTHEAST AND THE INITIAL MOTION ESTIMATE IS 070/05. THE
INCREASE IN FORWARD SPEED IS RELATED TO AN INCREASING WESTERLY MID-
TO UPPER-TROPOSPHERIC FLOW ASSOCIATED WITH AN UNUSUALLY DEEP
LONGWAVE TROUGH DIGGING OFFSHORE THE ATLANTIC SEABOARD. THE GFS
BRIEFLY SLOWS THE CYCLONE MOTION IN THE FIRST 12-24 HOURS OF THE
FORECAST...AND PERHAPS AS A RESULT THE WESTERN ATLANTIC TROUGH
FAILS TO CAPTURE DEBBY AS STRONGLY AS SHOWN BY THE ECMWF AND UKMET.
THE NEW NHC FORECAST IS FASTER THAN THE PREVIOUS ONE BUT IS NOT AS
QUICK AS THE ECMWF/UKMET/MULTI-MODEL CONSENSUS...BOTH BECAUSE OF
CONTINUITY AND RESPECT FOR THE GFS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/2100Z 29.5N  83.4W   35 KT  40 MPH...ON THE COAST
 12H  27/0600Z 29.5N  82.5W   30 KT  35 MPH...INLAND
 24H  27/1800Z 29.7N  81.4W   30 KT  35 MPH...INLAND
 36H  28/0600Z 30.0N  79.7W   30 KT  35 MPH...OVER WATER
 48H  28/1800Z 30.3N  77.7W   35 KT  40 MPH
 72H  29/1800Z 31.4N  74.1W   35 KT  40 MPH
 96H  30/1800Z 33.5N  71.0W   40 KT  45 MPH
120H  01/1800Z 36.6N  66.0W   45 KT  50 MPH
 
$$
FORECASTER KIMBERLAIN/FRANKLIN