937 
 WTNT45 KNHC 012044
 TCDAT5
  
 TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   1
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
 500 PM AST WED AUG 01 2012
  
 DURING THE DAY...VISIBLE SATELLITE IMAGES SHOWED THAT THE LOW-LEVEL
 CIRCULATION OF THE LOW PRESSURE SYSTEM TO THE EAST OF
 THE WINDWARD ISLANDS HAS BECOME BETTER DEFINED.  DEEP CONVECTION
 HAS PULSED A BIT...AND IS SOMEWHAT LACKING OVER THE NORTHERN PART
 OF THE CIRCULATION.  HOWEVER THE SYSTEM HAS NOW ACQUIRED SUFFICIENT
 ORGANIZATION TO BE CLASSIFIED AS A TROPICAL DEPRESSION.  THE
 INITIAL WIND SPEED IS SET AT 30 KT IN ACCORDANCE WITH DVORAK
 ESTIMATES FROM TAFB AND SAB.  FORECASTING INTENSITY CHANGE IS
 ALWAYS A CHALLENGE...AND IS PARTICULARLY TRUE IN THIS CASE.
 MODERATE VERTICAL SHEAR...ASSOCIATED WITH A LARGE UPPER-LEVEL LOW
 TO THE NORTH OF THE DEPRESSION...IS LIKELY TO AFFECT THE SYSTEM FOR
 THE NEXT COUPLE OF DAYS.  THUS ONLY SLOW STRENGTHENING IS
 ANTICIPATED DURING THE FIRST HALF OF THE FORECAST PERIOD.  LATER
 ON...THE INTENSITY FORECAST UNCERTAINTY INCREASES.  OUR BEST TWO
 GLOBAL MODELS ARE AT ODDS AS TO HOW THE SYSTEM WILL EVOLVE AS IT
 MOVES OVER THE CARIBBEAN.  THE GFS FORECASTS THE UPPER-LEVEL
 ENVIRONMENT TO BECOME QUITE CONDUCIVE FOR STRENGTHENING BY THE END
 OF THE FORECAST PERIOD...WHEREAS THE ECMWF MODEL SHOWS THE SYSTEM
 DEGENERATING INTO A TROPICAL WAVE.  THE OFFICIAL FORECAST LEANS
 TOWARD TO THE GFS...BUT TIME WILL TELL.
  
 THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 285/16.  GLOBAL MODELS
 DEPICT A STRONG MID-TROPOSPHERIC ANTICYCLONE TO THE NORTH OF THE
 TROPICAL CYCLONE FOR THE NEXT SEVERAL DAYS.  THIS STEERING PATTERN
 SHOULD CAUSE A WEST-NORTHWESTWARD TO WESTWARD MOTION AT ABOUT THE
 SAME SPEED THROUGH MUCH OF THE FORECAST PERIOD.  A WEAKNESS OVER
 THE GULF OF MEXICO COULD CAUSE SOME SLOWING AND BIT OF A
 NORTHWESTWARD TURN LATE IN THE PERIOD.  THE COMPUTER MODELS ARE IN
 GOOD AGREEMENT...AND THE NHC TRACK FORECAST IS NOT FAR FROM THE
 MODEL CONSENSUS.
  
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  01/2100Z 12.2N  49.0W   30 KT  35 MPH
  12H  02/0600Z 12.7N  51.3W   40 KT  45 MPH
  24H  02/1800Z 13.3N  54.5W   45 KT  50 MPH
  36H  03/0600Z 13.8N  57.7W   50 KT  60 MPH
  48H  03/1800Z 14.4N  60.9W   55 KT  65 MPH
  72H  04/1800Z 15.5N  67.0W   55 KT  65 MPH
  96H  05/1800Z 16.5N  73.0W   60 KT  70 MPH
 120H  06/1800Z 17.5N  78.0W   65 KT  75 MPH
  
 $$
 FORECASTER PASCH/BLAKE