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Tropical Storm JERRY (Text)

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TROPICAL STORM JERRY DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112013
500 AM AST TUE OCT 01 2013
 
SINCE THE PREVIOUS ADVISORY...STRONG NORTHWESTERLY VERTICAL WIND
SHEAR HAS COMPLETELY SQUASHED THE CONVECTIVE STRUCTURE OF JERRY. A
SHARP MID-/UPPER-LEVEL TROUGH TO THE NORTH OF JERRY IS DROPPING
SOUTHWARD AND IS INCREASING THE SHEAR ACROSS THE CYCLONE...AND ALSO
LIKELY ADVECTING DRY AIR INTO THE SYSTEM. A 0042Z PARTIAL ASCAT-B
SCATTEROMETER OVERPASS...WHICH WAS UNAVAILABLE FOR THE PREVIOUS
ADVISORY...INDICATED A COUPLE OF 38-KT SURFACE WIND VECTORS IN THE
WESTERN QUADRANT. IT IS ASSUMED THAT SLIGHTLY STRONGER WINDS EXIST
EAST OF THE CENTER WHERE VIGOROUS CONVECTION PREVIOUSLY EXISTED...
SO THE INTENSITY IS LOWERED TO 40 KT FOR THIS ADVISORY...WHICH IS
CONSISTENT WITH A BLEND OF SUBJECTIVE DVORAK SATELLITE INTENSITY
ESTIMATES FROM TAFB AND SAB.

IT IS DIFFICULT TO ASCERTAIN THE MOTION OF JERRY DUE TO THE LACK OF
CONTINUITY IN THE CONVECTIVE CLOUD PATTERN. HOWEVER...0559Z ATMS
AND 0608Z AMSU OVERPASSES SUGGEST THAT JERRY IS MOVING LITTLE. THE
GLOBAL AND REGIONAL MODELS ARE ALL IN FAIRLY GOOD AGREEMENT ON THE
CYCLONE REMAINING IN WEAK STEERING CONDITIONS FOR THE NEXT 24-36
HOURS...WHICH SHOULD RESULT IN SOME ERRATIC MOTION. BY 48 HOURS...
HOWEVER...THE NEXT MID-UPPER-LEVEL TROUGH THAT HAS JUST MOVED OFF
THE U.S. EAST COAST IS FORECAST TO BEGIN LIFTING OUT JERRY TO THE
NORTHEAST...AND THAT MOTION IS EXPECTED TO CONTINUE THROUGH 120
HOURS. THE NEW NHC FORECAST TRACK HAS AGAIN BEEN SHIFTED TO THE
EAST OF THE PREVIOUS ADVISORY TRACK...BUT IT REMAINS WEST OF THE
MULTI-MODEL CONSENSUS TVCA.
 
WATER VAPOR IMAGERY INDICATES THE SMALL UPPER-LEVEL LOW THAT THE
JERRY BRIEFLY BECAME ENTANGLED WITH DURING THE AFTERNOON OF 30 SEP
IS NOW EXITING THE SYSTEM TO THE SOUTHEAST. THE STRONG SHEAR ACROSS
THE CYCLONE CREATED BY THAT LOW AND THE UPPER-TROUGH TO THE NORTH
COULD CAUSE SOME ADDITIONAL WEAKENING TODAY. HOWEVER...BY 36-48
HOURS...AN UPPER-LEVEL SHORTWAVE RIDGE AHEAD OF THE U.S. EAST COAST
TROUGH IS EXPECTED TO PASS OVER THE CYCLONE...WHICH COULD ALLOW FOR
SOME SLIGHT RE-STRENGTHENING TO OCCUR. AFTER THAT...INCREASING
SOUTHWESTERLY VERTICAL SHEAR SHOULD CAUSE THE INTENSITY TO LEVEL
OFF...AND POSSIBLY INDUCE SOME WEAKENING BY DAY 5. THERE REMAINS A
LARGE SPREAD IN THE INTENSITY GUIDANCE RANGING FROM A WEAK TROPICAL
STORM IN THE HWRF AND ECMWF MODELS TO A HURRICANE IN THE LGEM
STATISTICAL-DYNAMICAL MODEL OUTPUT. GIVEN THE PROXIMITY OF DRY
MID-LEVEL AIR AND EXPECTED MODERATE SHEAR FOR MOST OF THE FORECAST
PERIOD...THE INTENSITY FORECAST WILL REMAIN ON THE CONSERVATIVE
SIDE AND IS SLIGHTLY LOWER THAN THE CONSENSUS MODEL ICON.

FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0900Z 27.2N  43.7W   40 KT  45 MPH
 12H  01/1800Z 27.2N  43.9W   40 KT  45 MPH
 24H  02/0600Z 27.5N  44.2W   40 KT  45 MPH
 36H  02/1800Z 28.2N  44.4W   45 KT  50 MPH
 48H  03/0600Z 29.0N  44.2W   45 KT  50 MPH
 72H  04/0600Z 30.7N  41.4W   45 KT  50 MPH
 96H  05/0600Z 32.0N  37.9W   40 KT  45 MPH
120H  06/0600Z 33.5N  33.5W   35 KT  40 MPH
 
$$
FORECASTER STEWART
 
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