000
WTPZ43 KNHC 260835
TCDEP3
TROPICAL STORM GENEVIEVE DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP082008
200 AM PDT SAT JUL 26 2008
 
A QUIKSCAT OVERPASS AT ABOUT 0230Z RETRIEVED WINDS OF 55-60 KT TO
THE NORTH OF THE CIRCULATION CENTER...BUT DUE TO RESOLUTION
LIMITATIONS OF THE INSTRUMENT THESE WERE LIKELY UNDERESTIMATES...
AND GENEVIEVE WAS PROBABLY STILL A HURRICANE AT THAT TIME. SINCE
THEN...HOWEVER...CLOUD TOPS HAVE WARMED AND DVORAK T-NUMBERS HAVE
DROPPED...SO GENEVIEVE APPEARS TO HAVE WEAKENED TO A TROPICAL
STORM.  BLENDING THE DVORAK T AND CI NUMBERS YIELDS AN INITIAL
INTENSITY ESTIMATE OF 60 KT. GENEVIEVE IS HEADED TOWARD
PROGRESSIVELY COOLER SEA-SURFACE TEMPERATURES...ALONG WITH A LITTLE
INCREASE IN SOUTHEASTERLY SHEAR...SO THE CYCLONE MIGHT HAVE JUST
GONE OVER THE BRINK INTO A PERMANENT WEAKENING TREND. ALL OF THE
OBJECTIVE GUIDANCE SAYS SO...AND THE OFFICIAL FORECAST OF DECAY
FOLLOWS THE INTENSITY CONSENSUS...AND SHOWS A SLIGHTLY FASTER RATE
OF DECLINE THAN THE SHIPS AND LGEM MODELS GIVEN THE SMALL SIZE OF
THE CYCLONE.

GENEVIEVE IS MOVING RIGHT ALONG THE PREVIOUS ADVISORY TRACK AT
280/11...AND THE NEW OFFICIAL FORECAST IS JUST AN UPDATE OF THE
PREVIOUS ONE. THE TRACK INVOLVES A SUBTLE TURN TO THE LEFT AT THE
LATITUDE OF THE MODEL CONSENSUS...AS THE EVENTUAL REMNANT LOW
SHOULD TURN DUE WESTWARD IN THE LOW-LEVEL FLOW IN A FEW DAYS. THE
GFDL AND HWRF TRACKS STILL TURN LEFT WELL TO THE NORTH OF THE
OFFICIAL FORECAST.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/0900Z 17.1N 119.1W    60 KT
 12HR VT     26/1800Z 17.5N 120.8W    55 KT
 24HR VT     27/0600Z 17.9N 122.9W    50 KT
 36HR VT     27/1800Z 18.4N 125.0W    40 KT
 48HR VT     28/0600Z 18.9N 127.0W    35 KT
 72HR VT     29/0600Z 19.5N 131.0W    25 KT...REMNANT LOW
 96HR VT     30/0600Z 19.5N 135.0W    20 KT...REMNANT LOW
120HR VT     31/0600Z 19.5N 139.0W    20 KT...REMNANT LOW
 
$$
FORECASTER KNABB