Tropical Storm GEORGETTE

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TROPICAL STORM GEORGETTE DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT THU AUG 26 2004
 
INFRARED SATELLITE IMAGERY INDICATES A LARGE BURST OF -85C TO -90C
CONVECTIVE TOPS HAS PERSISTED OVER AND NEAR THE CENTER OF TROPICAL
STORM GEORGETTE OVER THE PAST 5 HOURS AS THE RAGGED BANDING FEATURE
NOTED EARLIER IN THE NORTHERN SEMICIRCLE HAS DISSIPATED. THE
CENTRAL COLD COVER FEATURE HAS RESULTED IN A SCATTERING OF THE FIX
POSITIONS FROM THE THREE SATELLITE AGENCIES...AND THUS LESS
CONFIDENCE IN THE INITIAL POSITION AND MOTION. IN ANY EVENT
SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB...35 KT FROM SAB
AND AFWA. THE INITIAL INTENSITY OF 40 KT IS ESSENTIALLY A
COMPROMISE BETWEEN THE AGENCY ESTIMATES. THE SYSTEM CURRENTLY SHOWS
GOOD CIRRUS OUTFLOW OVER ALL QUADRANTS...EXCEPT THE EASTERN
QUADRANT WHERE OUTFLOW IS RESTRICTED DUE TO EASTERLY SHEAR. 
 
THE INITIAL MOTION IS A RATHER UNCERTAIN 305/14. WATER VAPOR
IMAGERY AND LARGE-SCALE MODEL ANALYSES INDICATE THAT GEORGETTE IS
SOUTH OF A NARROW MID/UPPER-LEVEL RIDGE AXIS ALONG 29N-30N. THE
GLOBAL MODELS FORECAST THE RIDGE TO STRENGTHEN AND BUILD
WESTWARD...WHICH SHOULD CAUSE GEORGETTE TO GRADUALLY TURN MORE
WESTWARD.  NHC TRACK GUIDANCE GENERALLY AGREES WITH THIS
SCENARIO...AND AS WAS THE CASE IN THE LAST MODEL CYCLE...THE
DYNAMICAL GUIDANCE CALLS FOR A WESTWARD TURN AFTER 36 HR WHILE THE
VARIOUS BAM MODELS...LBAR...AND NHC91 MOVE THE CYCLONE
WEST-NORTHWESTWARD TO NORTHWESTWARD THROUGH THE FORECAST PERIOD. 
THE OFFICIAL FORECAST FOLLOWS THE DYNAMICAL GUIDANCE WITH A WESTWARD
TURN AFTER 48 HR. THE NEW FORECAST TRACK IS ONLY SLIGHTLY NORTH OF
THE PREVIOUS TRACK DUE TO THE INITIAL POSITION AND MOTION. 

WATER VAPOR IMAGERY INDICATES THAT GEORGETTE IS CURRENTLY
EXPERIENCING SOME EASTERLY SHEAR. THE UNIVERSITY OF WISCONSIN CIMSS
WIND SHEAR ANALYSIS INDICATES 15-20 KT OF SHEAR OVER GEORGETTE. 
THE SHEAR IS FORECAST TO WEAKEN OVER THE NEXT 12-24 HOURS AS
INDICATED BY THE SHIPS GUIDANCE. STEADY INTENSIFICATION IS FORECAST
WITH GEORGETTE ATTAINING HURRICANE STATUS IN 36 HOURS...AND A PEAK
INTENSITY OF 70 KT IN 48 HOURS. THIS IS ALONG THE LINES OF BOTH
SHIPS AND THE GFDL. BEYOND THAT TIME FRAME...GEORGETTE IS FORECAST
TO TRACK OVER COOLER WATERS AND STEADILY WEAKEN. THE GFDL INTENSITY
FORECAST WAS PREFERRED OVER THE SHIPS BEYOND 48 HOURS AS THE SHIPS
MODEL ONLY WEAKENED GEORGETTE TO 55-60 KT BY DAY 5 DESPITE A TRACK
OVER 24-25 DEG C WATERS.  
 
FORECASTER COBB/PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0300Z 16.4N 108.8W    40 KT
 12HR VT     27/1200Z 17.4N 110.7W    50 KT
 24HR VT     28/0000Z 18.2N 113.2W    60 KT
 36HR VT     28/1200Z 18.7N 115.7W    65 KT
 48HR VT     29/0000Z 19.0N 118.0W    70 KT
 72HR VT     30/0000Z 19.5N 122.0W    60 KT
 96HR VT     31/0000Z 19.5N 126.5W    45 KT
120HR VT     01/0000Z 19.5N 131.0W    25 KT
 
 
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