Tropical Depression EMILY

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TROPICAL DEPRESSION EMILY DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052011
1100 PM EDT SAT AUG 06 2011
 
AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT THIS AFTERNOON FOUND
1000-FT FLIGHT-LEVEL WINDS AS HIGH AS 48 KT IN THE SOUTHERN
QUADRANT OF THE LOW-LEVEL CIRCULATION OF EMILY. HOWEVER...THESE
WINDS WERE OCCURRING NEAR ISOLATED SMALL CONVECTIVE CELLS AND WERE
NOT CONSIDERED TO BE REPRESENTATIVE OF THE STORM-SCALE CIRCULATION.
HOWEVER...OTHER FLIGHT-LEVEL AND SFMR SURFACE WIND DATA INDICATE
THAT EMILY IS A SOLID 30-KT DEPRESSION.
 
THE INITIAL MOTION ESTIMATE IS NORTHWARD OR 360/07 KT. EMILY IS
FORECAST TO MOVE SLOWLY NORTHWARD TONIGHT AND GRADUALLY TURN TOWARD
THE NORTHEAST ON SUNDAY AS THE SMALL CYCLONE MOVES AROUND THE
WESTERN PERIPHERY OF A SUBTROPICAL RIDGE THAT EXTENDS EAST-WEST
ALONG 28N LATITUDE. BY 24 HOURS...A SHORTWAVE TROUGH CURRENTLY
ALONG THE U.S. MID-ATLANTIC COAST IS EXPECTED TO CAPTURE EMILY AND
ACCELERATE IT TO THE EAST-NORTHEAST WITHIN THE MID-LATITUDE
WESTERLIES. EMILY IS FORECAST TO MERGE WITH A FRONTAL SYSTEM AROUND
THE 48-HOUR TIME PERIOD. THE FORECAST TRACK IS SIMILAR TO BUT A
LITTLE SOUTH OF THE PREVIOUS ADVISORY TRACK...AND IS ALONG THE
RIGHT SIDE OF THE NHC GUIDANCE ENVELOPE.
 
AFTER LOOKING REASONABLY IMPRESSIVE EARLIER THIS AFTERNOON...EMILY
IS NOW EXPERIENCING 10-15 OF NORTHEASTERLY SHEAR...WHICH HAS
ELONGATED BOTH THE CONVECTIVE PATTERN AND THE SURFACE WIND FIELD IN
A NORTHEAST-SOUTHWEST ORIENTATION. MODEST NORTHEAST TO EASTERLY
SHEAR IS EXPECTED TO CONTINUE FOR THE NEXT 12-18 HOURS...WHICH
SHOULD INHIBIT ANY SIGNIFICANT DEVELOPMENT. BY 24 HOURS...
HOWEVER...THE VERTICAL SHEAR IS FORECAST TO RELAX...WHICH MAY ALLOW
FOR SOME SLIGHT INTENSIFICATION TO OCCUR BEFORE WESTERLY WIND SHEAR
BEGINS TO AFFECT THE CYCLONE AND INDUCES WEAKENING. THE EXACT
TIMING OF MERGER WITH A WEAK FRONTAL SYSTEM THAT EXTENDS FROM THE
CAROLINAS TO NEAR BERMUDA IS DIFFICULT TO ASSESS THIS TIME OF THE
YEAR OVER SUCH WARM SSTS. ALTHOUGH DISSIPATION IS FORECAST TO OCCUR
SHORTLY AFTER THE 48-HOUR TIME PERIOD...IT WOULD NOT BE OUT OF THE
QUESTION FOR EMILY TO MAINTAIN ITS IDENTITY OUT TO 72 HOURS AS
INDICATED BY THE SHIPS/LGEM INTENSITY MODELS. THE OFFICIAL
INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND IS A
BLEND OF THE SHIPS/LGEM MODELS.
 
ANOTHER RECONNAISSANCE FLIGHT IS SCHEDULED FOR SUNDAY AFTERNOON.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/0300Z 27.4N  78.2W   30 KT  35 MPH
 12H  07/1200Z 29.2N  76.9W   35 KT  40 MPH
 24H  08/0000Z 30.9N  74.0W   35 KT  40 MPH
 36H  08/1200Z 32.5N  69.1W   35 KT  40 MPH
 48H  09/0000Z 34.0N  62.0W   30 KT  35 MPH
 72H  10/0000Z...DISSIPATED
 
$$
FORECASTER STEWART
 
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