548 
 WTPZ42 KNHC 170240
 TCDEP2
 TROPICAL STORM FAUSTO DISCUSSION NUMBER   4
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072008
 800 PM PDT WED JUL 16 2008
  
 THE CENTER IS VERY DIFFICULT TO LOCATE...BUT IS BELIEVED TO BE NEAR
 THE NORTHERN EDGE OF THE MAIN CONVECTIVE BLOB.  A BLEND OF THE MOST
 RECENT DVORAK CLASSIFICATIONS GIVES 40 KT FOR THE INITIAL
 INTENSITY...ALTHOUGH GIVEN THE UNCERTAIN CENTER LOCATION I AM NOT
 ESPECIALLY CONFIDENT IN THIS ASSESSMENT.  NORTHEASTERLY SHEAR IS
 HAMPERING DEVELOPMENT...AND THE GLOBAL MODELS SUGGEST THAT THIS
 COULD REMAIN A FACTOR FOR THE NEXT FEW DAYS.  THERE IS CONSIDERABLE
 SPREAD IN THE INTENSITY GUIDANCE.  THE SHIPS MODEL IS MOST
 AGGRESSIVE...BRINGING FAUSTO TO ABOUT 80 KT IN 3 DAYS...WHILE THE
 HWRF SHOWS VIRTUALLY NO STRENGTHENING AT ALL.    IN BETWEEN ARE THE
 LGEM AND GFDL MODELS...WITH WHICH THE OFFICIAL FORECAST IS IN GOOD
 AGREEMENT.  THE SHIPS MODEL DIAGNOSES ONLY 10 KT OF SHEAR FROM THE
 GFS ANALYSIS...WHICH SEEMS UNREALISTICALLY LOW GIVEN THE CURRENT
 CLOUD PATTERN AND UPPER-LEVEL SATELLITE WINDS.
 
 THE INITIAL MOTION IS A HIGHLY UNCERTAIN 280/20.  IT APPEARS THAT
 THIS MORE RAPID MOTION MAY BE THE RESULT OF THE CIRCULATION CENTER
 ROTATING WITHIN A LARGER CYCLONIC GYRE...OR PERHAPS THERE IS A
 PROPAGATION COMPONENT TOWARD THE SHEARED CONVECTION.  IN EITHER
 EVENT...I DO NOT EXPECT THIS RAPID MOTION TO PERSIST.  THE TRACK
 FORECAST PHILOSOPHY IS UNCHANGED FROM THE PREVIOUS ADVISORY...AND
 CALLS FOR FAUSTO TO MOVE WEST-NORTHWESTWARD TO THE SOUTH OF THE
 SUBTROPICAL RIDGE.  THE ECMWF IS AN INTERESTING OUTLIER...
 THOUGH...TAKING FAUSTO ABOUT 300 NM TO THE NORTHWEST OF THE OTHER
 MODELS BY 5 DAYS.  THIS APPEARS TO BE DUE TO THE FORECAST
 AMPLIFICATION OF A MID-LEVEL VORTICITY MAX CURRENTLY OVER EXTREME
 WESTERN TEXAS AS IT MOVES WESTWARD TOWARD THE BAJA PENINSULA.  THIS
 FEATURE THEN PLAYS A ROLE IN BREAKING DOWN THE SUBTROPICAL RIDGE
 WEST OF BAJA IN ABOUT 3-4 DAYS.  THE EVOLUTION OVER THE COLD WATERS
 WEST OF BAJA IN PARTICULAR SEEMS UNREALISTIC...SO FOR THE
 MOMENT...THIS SCENARIO IS BEING DISCOUNTED.  
 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      17/0300Z 11.8N 101.7W    40 KT
  12HR VT     17/1200Z 12.2N 104.0W    45 KT
  24HR VT     18/0000Z 12.9N 106.3W    50 KT
  36HR VT     18/1200Z 13.5N 108.4W    55 KT
  48HR VT     19/0000Z 13.9N 110.2W    60 KT
  72HR VT     20/0000Z 15.0N 113.0W    65 KT
  96HR VT     21/0000Z 16.5N 116.5W    70 KT
 120HR VT     22/0000Z 18.0N 121.0W    65 KT
  
 $$
 FORECASTER FRANKLIN