000
WTPZ43 KNHC 230852
TCDEP3
TROPICAL STORM GENEVIEVE DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP082008
200 AM PDT WED JUL 23 2008
 
LATEST INFRARED SATELLITE IMAGERY SHOWS A LARGE SHAPELESS MASS OF
VERY COLD CLOUD TOPS NEAR THE CENTER OF CIRCULATION.  SUCH A
PATTERN NORMALLY SIGNALS AN INTERRUPTION IN THE DEVELOPMENT OF A
TROPICAL CYCLONE.  ACCORDINGLY...THE INITIAL INTENSITY IS HELD AT
55 KT FOR THIS ADVISORY.  THE INTENSITY FORECAST PHILOSOPHY REMAINS
CHALLENGING. VERTICAL SHEAR IS EXPECTED TO WEAKEN BUT GENEVIEVE IS
CURRENTLY MOVING OVER A SMALL AREA OF RELATIVELY COOLER SSTS LEFT
IN THE WAKE OF FAUSTO.  THESE TWO ENVIRONMENTAL FACTORS SHOULD
OFFSET EACH OTHER RESULTING IN SLOW OR POSSIBLY NO DEVELOPMENT
DURING THE FIRST 12-24 HOURS. THEREAFTER...THE CYCLONE WILL MOVE
BACK OVER WARMER WATERS ALLOWING ABOUT A TWO-DAY WINDOW FOR
STRENGTHENING PRIOR TO THE ONSET OF HIGHER VERTICAL SHEAR IN ABOUT
3 DAYS.  THE OFFICIAL INTENSITY FORECAST IS ESSENTIALLY AN UPDATE
OF THE PREVIOUS ONE AND IS IN CLOSEST AGREEMENT WITH THE LGEM
STATISTICAL MODEL.
 
A RECENT AMSU PASS SUGGESTED THAT THE LOW-LEVEL CIRCULATION WAS A
LITTLE NORTH OF THE PREVIOUS TRACK. HOWEVER...I AM RELUCTANT TO
COMPLETELY RELOCATE THE CENTER AT NIGHT AND HAVE OPTED TO SPLIT THE
DIFFERENCE BETWEEN THE EXTRAPOLATED CENTER POSITION AND THE AMSU
CENTER ESTIMATE. THE INITIAL MOTION IS NOW ESTIMATED TO BE 280/08.
TRACK MODELS CONTINUE TO PROVIDE VASTLY DIFFERENT FORECASTS RANGING
FROM A NORTHWESTWARD MOTION TO A SOUTHWESTWARD MOTION. THOSE MODELS
WHICH SHOW A SOUTHWESTWARD MOTION ALSO FORECAST A SHALLOW SYSTEM. 
SINCE THERE IS NO INDICATION THAT GENEVIEVE WILL SUDDENLY
WEAKEN...THE OFFICIAL FORECAST LEANS MORE TOWARDS THE REMAINING
MODELS AND INDICATES A WEST-NORTHWESTWARD MOTION. THIS RESULTS IN A
NORTHWARD SHIFT OF THE TRACK...BUT THE OFFICIAL FORECAST STILL LIES
SOUTH OF THE DYNAMICAL MODEL CONSENSUS AT DAYS 3-5. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0900Z 14.7N 108.7W    55 KT
 12HR VT     23/1800Z 14.8N 109.9W    60 KT
 24HR VT     24/0600Z 14.9N 111.4W    60 KT
 36HR VT     24/1800Z 15.0N 112.9W    65 KT
 48HR VT     25/0600Z 15.1N 114.6W    65 KT
 72HR VT     26/0600Z 15.5N 117.5W    60 KT
 96HR VT     27/0600Z 16.0N 121.0W    50 KT
120HR VT     28/0600Z 16.5N 124.5W    45 KT
 
$$
FORECASTER RHOME