042 
 WTNT44 KNHC 210900
 TCDAT4
 HURRICANE DEAN DISCUSSION NUMBER  33
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 500 AM EDT TUE AUG 21 2007
  
 DEAN MADE LANDFALL ON THE EAST COAST OF THE YUCATAN PENINSULA NEAR
 THE CRUISE SHIP PORT OF COSTA MAYA AROUND 0830 UTC...AND THE EYE IS
 NOW JUST INLAND.  OBSERVATIONS FROM AN AIR FORCE HURRICANE HUNTER
 PLANE INDICATE THAT THE HURRICANE WAS INTENSIFYING RIGHT UP TO
 LANDFALL.  A PEAK FLIGHT-LEVEL WIND OF 165 KT WAS MEASURED JUST
 NORTH OF THE EYE.  MAXIMUM SURFACE WINDS FROM THE SFMR WERE 124
 KT...BUT IT IS HIGHLY LIKELY THAT THE MAXIMUM SURFACE WIND SPEED
 WAS NOT REPORTED BY THE SFMR INSTRUMENT.  A GPS DROPSONDE IN THE
 NORTHERN EYEWALL MEASURED A WIND SPEED OF 178 KT AVERAGED OVER THE
 LOWEST 150 METERS OF THE SOUNDING.  BASED ON THE DROPSONDE AND THE
 FLIGHT-LEVEL WINDS...THE INTENSITY IS SET AT 145 KT.  A DROPSONDE
 IN THE EYE MEASURED A CENTRAL PRESSURE OF 906 MB JUST PRIOR TO
 LANDFALL.  SOME HISTORIC NOTES ARE IN ORDER HERE.  THE 906 MB
 CENTRAL PRESSURE IS THE NINTH LOWEST ON RECORD FOR AN ATLANTIC
 BASIN HURRICANE...AND THE THIRD LOWEST AT LANDFALL BEHIND THE 1935
 LABOR DAY HURRICANE IN THE FLORIDA KEYS AND HURRICANE GILBERT OF
 1988 IN CANCUN MEXICO.  DEAN IS ALSO THE FIRST CATEGORY FIVE
 HURRICANE TO MAKE LANDFALL IN THE ATLANTIC BASIN SINCE ANDREW OF
 1992.
  
 DEAN WILL WEAKEN AS IT TRAVERSES THE YUCATAN PENINSULA AND
 THE AMOUNT OF WEAKENING WILL DEPEND ON HOW LONG THE CENTER REMAINS
 OVER LAND.  OUR CURRENT THINKING IS THAT THE CYCLONE WILL STILL BE
 A BORDERLINE CAT 1/2 HURRICANE WHEN IT EMERGES OVER THE BAY OF
 CAMPECHE...BUT THERE IS CONSIDERABLE UNCERTAINTY IN THIS FORECAST.
 ASSUMING THAT THE INNER CORE IS NOT TOO DISRUPTED BY ITS
 INTERACTION WITH LAND...DEAN SHOULD REGAIN MAJOR HURRICANE STATUS
 BEFORE ITS FINAL LANDFALL IN MAINLAND MEXICO.
 
 INITIAL MOTION IS ESTIMATED TO BE 285/17.  DEEP LAYER HIGH PRESSURE
 NEAR THE NORTHERN GULF COAST SHOULD STEER THE HURRICANE ON A
 WEST-NORTHWESTWARD TO WESTWARD HEADING FOR THE NEXT COUPLE OF DAYS. 
 THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ONE.
 
 THE HURRICANE WARNING IS EXTENDED WESTWARD ALONG THE BAY OF CAMPECHE
 COASTLINE OF MEXICO.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      21/0900Z 18.7N  87.8W   145 KT
  12HR VT     21/1800Z 19.1N  90.4W    85 KT...INLAND
  24HR VT     22/0600Z 19.6N  93.9W    95 KT...OVER BAY OF CAMPECHE
  36HR VT     22/1800Z 20.1N  96.8W   105 KT...INLAND
  48HR VT     23/0600Z 20.5N 100.0W    25 KT...INLAND...DISSIPATING
  72HR VT     24/0600Z...DISSIPATED
  
 $$
 FORECASTER PASCH/BROWN