984 
 WTNT44 KNHC 182024
 TCDAT4
 HURRICANE DEAN DISCUSSION NUMBER  23
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 500 PM EDT SAT AUG 18 2007
  
 THERE HAVE BEEN NO SIGNIFICANT CHANGES IN THE STRUCTURE OF DEAN
 DURING THE PAST SEVERAL HOURS. THE LAST RECONNAISSANCE AIRCRAFT
 INTO THE EYE MEASURED 930 MB AND THE REPORTED WINDS SUPPORT AN
 INITIAL INTENSITY OF 130 KNOTS. HOWEVER...THE CREW OBSERVED A
 DOUBLE EYEWALL AND THE PRESENCE OF THIS FEATURE WILL PROBABLY
 RESULT IN SHORT TERM FLUCTUATIONS IN INTENSITY. THE SATELLITE
 PRESENTATION IS OUTSTANDING WITH A WELL DEFINED EYE...NUMEROUS
 SPIRAL BANDS AND AN EXPANDING OUTFLOW. WITH AN ENVIRONMENT OF LOW
 SHEAR AND VERY HIGH OCEANIC HEAT CONTENT BETWEEN THE CAYMAN ISLANDS
 AND YUCATAN...SOME ADDITIONAL INTENSIFICATION IS POSSIBLE. IN
 FACT...DEAN COULD BECOME A POTENTIALLY CATASTROPHIC CATEGORY FIVE
 HURRICANE AT ANY TIME BEFORE IT REACHES YUCATAN.
 
 THE HURRICANE IS HEADING ON A STEADY WEST-NORTHWESTWARD TRACK OR 285
 DEGREES AT 16 KNOTS. THE STRONG HIGH TO THE NORTH OF THE HURRICANE
 IS EXPECTED TO BUILD WESTWARD AS INDICATED BY THE LATEST GLOBAL
 MODEL RUNS. THIS PATTERN CALLS FOR NO SIGNIFICANT CHANGE IN TRACK
 OR SPEED THROUGH 5 DAYS...BUT PERHAPS WITH A SLIGHT TURN MORE TO THE
 WEST IN A DAY OR SO. THE GFDL CONTINUES TO BE ON THE NORTHERN SIDE
 OF THE GUIDANCE ENVELOPE AND IS THE ONLY MODEL THAT BRINGS THE
 HURRICANE OVER THE SOUTHERN TEXAS COAST. THE OFFICIAL FORECAST GOES
 ALONG WITH THE CONSENSUS OF THE DYNAMICAL MODELS AND KEEPS DEAN IN
 THE BAY OF CAMPECHE OR SOUTHERN GULF OF MEXICO BY DAY FOUR. THERE
 COULD BE VERY UNCERTAIN DAYS AHEAD SINCE THE GFDL HAS HAD A VERY
 RELIABLE TRACK RECORD.
 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      18/2100Z 16.1N  70.2W   130 KT
  12HR VT     19/0600Z 16.8N  72.6W   135 KT
  24HR VT     19/1800Z 17.7N  76.0W   135 KT
  36HR VT     20/0600Z 18.5N  79.3W   125 KT
  48HR VT     20/1800Z 19.5N  83.0W   140 KT
  72HR VT     21/1800Z 21.5N  90.0W   100 KT
  96HR VT     22/1800Z 23.0N  96.0W   105 KT
 120HR VT     23/1800Z 24.5N 101.5W    40 KT...INLAND
  
 $$
 FORECASTER AVILA