028 
 WTNT44 KNHC 200300
 TCDAT4
 HURRICANE DEAN DISCUSSION NUMBER  28
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 1100 PM EDT SUN AUG 19 2007
  
 THE EYE OF DEAN HAS BEEN PASSING JUST SOUTH OF JAMAICA SINCE ABOUT
 1900 UTC AND HAS JUST CROSSED THE LONGITUDE OF NEGRIL ON THE
 WESTERN END OF THE ISLAND.  THE CENTER CAME WITHIN ABOUT 20 N MI OF
 PORTLAND POINT ON THE SOUTH-CENTRAL COAST...CLOSE ENOUGH TO BRING
 HURRICANE-FORCE WINDS TO KINGSTON.  WHILE PASSING BY JAMAICA...
 SATELLITE IMAGERY SUGGESTED THE EYE DIAMETER WAS GRADUALLY
 SHRINKING.  AN AIR FORCE HURRICANE HUNTER AIRCRAFT ARRIVED IN THE
 EYE OF DEAN AT 0130 UTC AND REVEALED THAT THE PRESSURE HAD FALLEN
 TO NEAR 925 MB...AND THAT DEAN NOW HAS A SINGLE EYEWALL AT A
 DIAMETER OF ABOUT 15 N MI.  MAXIMUM SURFACE WINDS FROM THE SFMR
 HAVE BEEN 121 KT...AND FLIGHT-LEVEL WINDS HAVE BEEN AS HIGH AS 143
 KT...BOTH OF WHICH SUPPORT MAINTAINING THE ADVISORY INTENSITY AT
 125 KT.
  
 DEAN IS HEADING TOWARD 280 DEGREES AT ABOUT 17 KT WITH STEERING
 PROVIDED BY A STRENGTHENING MID-LEVEL RIDGE OVER THE SOUTHEASTERN
 UNITED STATES.  THE MODELS ALL AGREE THAT THE RIDGE WILL GET EVEN
 STRONGER AND MOVE A LITTLE WESTWARD WITH DEAN...MEANING THAT DEAN
 WILL PROBABLY MOVE IN A RATHER STRAIGHT LINE UNTIL FINAL LANDFALL
 IN MEXICO.  OVERALL THE MODELS HAVE AGAIN EDGED A LITTLE
 SOUTHWARD...AND SO HAS THE OFFICIAL FORECAST.  THE NOAA
 GULFSTREAM-IV JET CONDUCTED A SYNOPTIC SURVEILLANCE MISSION THIS
 EVENING TO PROVIDE DATA FOR THE 0000 UTC MODEL CYCLE.  THE JET WILL
 CONTINUE TO FLY MISSIONS EVERY 12 HOURS TO COLLECT DATA THROUGH THE
 12Z MODEL CYCLE TUESDAY MORNING.
  
 ALL OF THE OBJECTIVE GUIDANCE CALLS FOR STRENGTHENING IN THE
 NORTHWESTERN CARIBBEAN WHERE THE SHEAR WILL REMAIN WEAK AND THE
 OCEAN HEAT CONTENT VERY HIGH.  THE OFFICIAL FORECAST FOLLOWS SUIT
 AND INDICATES THAT DEAN COULD REACH CATEGORY FIVE STATUS DURING THE
 NEXT DAY OR SO.  THE HURRICANE WILL WEAKEN WHILE OVER YUCATAN IN
 PROPORTION TO JUST HOW LONG IT SPENDS OVER LAND.  THE OPPORTUNITY
 FOR RESTRENGTHENING OVER THE SOUTHWESTERN GULF LIKEWISE DEPENDS ON
 THE EXACT TRACK...AND THAT WINDOW HAS BEEN SHORTENING WITH THE
 SOUTHWARD SHIFTS IN TRACK.  ALTHOUGH NOT EXPLICITLY INDICATED IN
 THE NEW OFFICIAL FORECAST...IT IS STILL POSSIBLE THAT DEAN COULD
 RESTRENGTHEN AND AGAIN REACH MAJOR HURRICANE STATUS PRIOR TO FINAL
 LANDFALL ALONG THE COAST OF MAINLAND MEXICO.
 
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      20/0300Z 17.6N  78.8W   125 KT
  12HR VT     20/1200Z 18.0N  81.4W   130 KT
  24HR VT     21/0000Z 18.5N  84.9W   140 KT
  36HR VT     21/1200Z 19.2N  88.4W   105 KT...INLAND
  48HR VT     22/0000Z 19.8N  91.9W    80 KT
  72HR VT     23/0000Z 21.0N  99.0W    55 KT...INLAND
  96HR VT     24/0000Z...DISSIPATED
  
 $$
 FORECASTER KNABB