000
WTNT42 KNHC 110254
TCDAT2
 
TROPICAL STORM GABRIELLE DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072013
1100 PM AST TUE SEP 10 2013
 
SATELLITE IMAGERY SHOWS THAT THE PRIMARY AREA OF DEEP CONVECTION
ASSOCIATED WITH GABRIELLE HAS BECOME DISPLACED WELL TO THE EAST OF
THE LOW-LEVEL CENTER THIS EVENING...DUE TO STRONG SOUTHWESTERLY
SHEAR.  RADAR IMAGES FROM BERMUDA HAVE BEEN EXTREMELY HELPFUL IN
TRACKING THE PROGRESS OF THE STORM THIS EVENING.  THE RADAR DATA
SHOW THAT GABRIELLE HAS DECELERATED AND THAT SOME SHALLOW
CONVECTIVE BANDS ARE WRAPPING AROUND THE NORTHEASTERN PORTION OF
THE CIRCULATION.  THE INITIAL WIND SPEED REMAINS 50 KT...WHICH IS
BASED ON THE EARLIER AIRCRAFT DATA AND RECENT OBSERVATIONS OF 35
TO 45 KT SUSTAINED WINDS AT WEATHER STATIONS ON BERMUDA.  ANOTHER
AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT WILL BE INVESTIGATING
THE TROPICAL STORM OVERNIGHT.

THE INITIAL MOTION ESTIMATE IS 355/7 KT. GABRIELLE SHOULD TURN
NORTH-NORTHWESTWARD ON WEDNESDAY AS IT IS STEERED AROUND THE
NORTHEASTERN SIDE OF A MID- TO UPPER-LEVEL LOW LOCATED EAST OF
FLORIDA. IN A COUPLE OF DAYS...THE DEEP LAYER FLOW OFF THE EAST
COAST OF THE UNITED STATES IS FORECAST TO TURN SOUTHWESTWARD AND
STRENGTHEN AHEAD OF A MID-LATITUDE TROUGH. THIS SHOULD CAUSE
GABRIELLE TO TURN NORTHEASTWARD AND BEGIN TO ACCELERATE. THE TRACK
MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THIS SCENARIO...BUT HAS
SHIFTED A LITTLE WESTWARD DURING THE FIRST 36 HOURS.
CONSEQUENTLY...THE NHC TRACK HAS BEEN NUDGED WESTWARD TO BE IN
BETTER AGREEMENT WITH THE GUIDANCE. AFTER 36 HOURS...THE UPDATED
NHC TRACK IS CLOSE TO THE PREVIOUS ADVISORY.

GABRIELLE IS FORECAST TO REMAIN OVER WARM WATER BUT WITHIN 
MODERATE TO STRONG SOUTHWESTERLY SHEAR DURING THE NEXT FEW DAYS. 
THE SHEAR IS LIKELY TO PREVENT ANY SIGNIFICANT STRENGTHENING AND 
THE LATEST INTENSITY GUIDANCE NOW SHOWS LITTLE CHANGE IN STRENGTH
DURING THE NEXT DAY OR SO.  AS A RESULT...THE NHC INTENSITY
FORECAST HAS BEEN ADJUSTED SLIGHTLY LOWER.  IF ORGANIZED DEEP
CONVECTION DOES NOT REDEVELOP IN ASSOCIATION WITH THE CYCLONE...
GABRIELLE COULD DEGENERATE INTO A REMNANT LOW TOMORROW.  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  11/0300Z 32.0N  65.0W   50 KT  60 MPH
 12H  11/1200Z 32.8N  65.3W   50 KT  60 MPH
 24H  12/0000Z 33.6N  66.0W   45 KT  50 MPH
 36H  12/1200Z 34.5N  66.6W   45 KT  50 MPH
 48H  13/0000Z 36.3N  66.6W   45 KT  50 MPH
 72H  14/0000Z 44.5N  61.5W   45 KT  50 MPH
 96H  15/0000Z 54.0N  47.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  16/0000Z...DISSIPATED
 
$$
FORECASTER BROWN