259 
 WTPZ45 KNHC 282025
 TCDEP5
 HURRICANE DARBY DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 2 PM PDT WED JUL 28 2004
  
 THE CLOUD PATTERN HAS IMPROVED SIGNIFICANTLY DURING THE PAST FEW
 HOURS. DARBY HAS DEVELOPED A WELL-DEFINED EYE SURROUNDED BY A
 CENTRAL DENSE OVERCAST AND BANDING FEATURES. BECAUSE T-NUMBERS HAVE
 INCREASED TO 5.0 ON THE DVORAK SCALE...THE INITIAL INTENSITY HAS
 BEEN ADJUSTED TO 90 KNOTS. SINCE DARBY IS EXPECTED TO CROSS THE 26
 DEGREE ISOTHERM IN ABOUT 12 TO 18 HOURS AND THE SHEAR IS FORECAST TO
 INCREASE...THERE IS ONLY LESS THAN A DAY FOR DARBY TO FURTHER
 STRENGTHEN...IF AT ALL. THEREAFTER...A GRADUAL WEAKENING SHOULD
 BEGIN.
 
 THE STEERING PATTERN HAS NOT CHANGED. THE HURRICANE CONTINUES TO
 MOVE TOWARD THE WEST-NORTHWEST ABOUT 11 KNOTS AROUND A SUBTROPICAL
 RIDGE. A WEAKNESS LOCATED TO THE WEST OF THE RIDGE WILL ALLOW DARBY
 TO CONTINUE ON THIS GENERAL TRACK.  HOWEVER...AS DARBY WEAKENS...IT
 SHOULD BEGIN TO BE STEERED BY THE LOW-LEVEL FLOW AND THE CYCLONE IS
 EXPECTED TO TURN MORE TO THE WEST IN 4 AND 5 DAYS.  DURING THE
 FIRST 2 TO 3 DAYS WHEN DARBY IS EXPECTED TO BE A STRONG
 SYSTEM...THE OFFICIAL FORECAST IS VERY CLOSE TO THE GLOBAL MODEL
 CONSENSUS. THEREAFTER...AS WEAKENING BEGINS AND THE CYCLONE BECOMES
 SHALLOW...THE FORECAST TRACK IS CLOSER TO BAMM OR BAMS MODELS. 
  
 FORECASTER AVILA
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      28/2100Z 16.2N 124.5W    90 KT
  12HR VT     29/0600Z 16.9N 126.2W    90 KT
  24HR VT     29/1800Z 17.5N 128.5W    80 KT
  36HR VT     30/0600Z 18.5N 130.5W    70 KT
  48HR VT     30/1800Z 19.0N 132.5W    60 KT
  72HR VT     31/1800Z 19.5N 137.0W    50 KT
  96HR VT     01/1800Z 20.0N 142.0W    40 KT
 120HR VT     02/1800Z 20.0N 147.0W    35 KT
  
  
 $$