Tropical Storm FRANKLIN

ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL STORM FRANKLIN DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062011
500 AM EDT SAT AUG 13 2011
 
DURING THE PAST SEVERAL HOURS...SATELLITE IMAGES INDICATE THAT A
LARGE BURST OF CONVECTION FORMED NEAR OR JUST TO THE EAST OF THE
CENTER.  AN AMSR-E MICROWAVE PASS AT 0553 UTC SUGGESTS THE CENTRAL
FEATURES OF THE SYSTEM WERE BECOMING BETTER-DEFINED WITH MORE
CURVATURE NOTED.  DVORAK SATELLITE ESTIMATES WERE 30 KT AND 35 KT
FROM TAFB/SAB WITH AN AMSU-BASED ESTIMATE FROM UW-CIMSS OF 37 KT. 
GIVEN THE SIGNIFICANT INCREASE IN THE CONVECTION AND STRUCTURAL
IMPROVEMENTS IN MICROWAVE IMAGERY...THE INTENSITY IS SET TO 35
KT...MAKING THIS SYSTEM THE SIXTH TROPICAL STORM OF THE YEAR.
 
FRANKLIN DOES NOT HAVE MUCH TIME LEFT TO INTENSIFY AS IT WILL SOON
BE CROSSING THE 26C ISOTHERM.  VERTICAL WIND SHEAR IS ALSO FORECAST
TO INCREASE DUE TO AN UPPER-LEVEL TROUGH CATCHING THE STORM FROM
BEHIND.  THUS...ONLY A SMALL INCREASE IN STRENGTH IS SHOWN IN THE
NHC FORECAST...SIMILAR TO A BLEND OF THE SHIPS AND LGEM MODELS.  IT
SHOULD BE NOTED THAT THESE TYPES OF NORTHEASTWARD MOVING SYSTEMS
HAVE HISTORICALLY BEEN DIFFICULT TO FORECAST...AND IT WOULD NOT BE
SURPRISING IF THE STORM BRIEFLY BECOMES A LITTLE STRONGER THAN
PREDICTED.  
 
THE INITIAL MOTION HAS TURNED A LITTLE TO THE LEFT AND IS ESTIMATED
AT 055/17.  FRANKLIN IS BEING STEERED ALONG THE NORTHWESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE WITHIN MID-LATITUDE WEST-
SOUTHWESTERLY FLOW.  MODEL GUIDANCE IS TIGHTLY CLUSTERED ON A TRACK
TOWARD THE EAST-NORTHEAST TODAY...FOLLOWED BY A MOTION TOWARD THE
EAST AS THE STORM MOVES AROUND THE RIDGE.  THE LATEST FORECAST IS
BASICALLY AN UPDATE OF THE PREVIOUS NHC ADVISORY...AND LIES JUST TO
THE NORTH OF THE ATLANTIC MULTI-MODEL CONSENSUS.  A COLD FRONT CAN
BE SEEN A FEW HUNDRED MILES TO THE NORTHWEST OF FRANKLIN...AND THIS
FEATURE...ALONG WITH COOLER SSTS AND INCREASING SHEAR...SHOULD
CAUSE EXTRATROPICAL TRANSITION WITHIN ABOUT 24 HOURS.  THE SYSTEM
SMALL SYSTEM SHOULD BECOME ABSORBED BY THE FRONT IN ABOUT 3 DAYS.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  13/0900Z 37.9N  60.4W   35 KT  40 MPH
 12H  13/1800Z 39.0N  57.4W   40 KT  45 MPH
 24H  14/0600Z 40.0N  52.9W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  14/1800Z 40.4N  48.3W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  15/0600Z 40.0N  43.7W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  16/0600Z...DISSIPATED
 
$$
FORECASTER BLAKE
 
NNNN