240 
 WTNT44 KNHC 202033
 TCDAT4
 HURRICANE DEAN DISCUSSION NUMBER  31
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 500 PM EDT MON AUG 20 2007
  
 COMMUNICATIONS PROBLEMS ARE PREVENTING THE RECEIPT OF MOST DATA FROM
 THE AIR FORCE RECONNAISSANCE AIRCRAFT THIS AFTERNOON...ALTHOUGH A
 1930Z VORTEX FIX WAS RECEIVED. AT THAT TIME THE MINIMUM PRESSURE
 WAS 918 MB...WITH MAXIMUM FLIGHT-LEVEL WINDS OF 151 KT. EARLIER IN
 THE FLIGHT...A PEAK SFMR WIND OF 123 KT WAS OBSERVED.  DVORAK
 CLASSIFICATIONS FROM TAFB AND SAB WERE 127 KT AT 18Z.  BASED ON
 THESE DATA...THE INITIAL INTENSITY IS HELD AT 130 KT. ALL OBJECTIVE
 GUIDANCE SHOWS ADDITIONAL INTENSIFICATION OVER THE DEEP WARM WATERS
 OF THE WESTERN CARIBBEAN...AND DEAN COULD REACH CATEGORY FIVE
 STATUS BEFORE MAKING LANDFALL. A 15Z MICROWAVE PASS SHOWS A PARTIAL
 OUTER EYEWALL...BUT THIS WILL PROBABLY NOT HAVE ENOUGH TIME TO
 INDUCE ANY WEAKENING BEFORE LANDFALL.  DEAN IS EXPECTED TO MAINTAIN
 HURRICANE STRENGTH AS IT TRAVERSES THE YUCATAN PENINSULA...AND
 APPROACH MAJOR HURRICANE STRENGTH AGAIN BEFORE ITS FINAL LANDFALL.
  
 THE INITIAL MOTION IS 275/17.  DEAN IN EXPECTED TO MAINTAIN A TRACK
 BETWEEN WEST AND WEST-NORTHWEST TO THE SOUTH OF THE WESTWARD-
 BUILDING SUBTROPICAL RIDGE.  MOST OF THE DYNAMICAL MODEL GUIDANCE
 HAS TRENDED SOUTH AND THE OFFICIAL FORECAST HAS BEEN NUDGED
 SOUTHWARD.  ALL THE LARGE-SCALE MODELS TAKE THE MID-LEVEL VORTICITY
 OF DEAN WEST-SOUTHWESTWARD ACROSS THE MOUNTAINS OF CENTRAL
 MEXICO...AND THE OFFICIAL FORECAST NOW SHOWS A LEFTWARD BEND OF THE
 TRACK AFTER FINAL LANDFALL.  I DO NOT ACTUALLY EXPECT A WELL-
 DEFINED SURFACE CIRCULATION TO EXIST AT 72 HOURS...BUT A POINT IS
 PROVIDED SO THAT IT DOESN'T APPEAR THAT THE TRACK ENDS IN THE GULF
 OF MEXICO.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      20/2100Z 18.2N  84.2W   130 KT
  12HR VT     21/0600Z 18.5N  86.7W   140 KT
  24HR VT     21/1800Z 19.3N  90.2W    75 KT...INLAND
  36HR VT     22/0600Z 20.2N  93.6W    85 KT
  48HR VT     22/1800Z 21.0N  97.0W    95 KT
  72HR VT     23/1800Z 21.5N 103.0W    30 KT...INLAND
  96HR VT     24/1800Z...DISSIPATED
  
 $$
 FORECASTER FRANKLIN