047 
 WTPZ45 KNHC 062053
 TCDEP5
 TROPICAL STORM NORBERT DISCUSSION NUMBER  12
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
 200 PM PDT MON OCT 06 2008
 
 SATELLITE IMAGERY SUGGEST THAT NORBERT CONTINUES TO GRADUALLY BECOME
 BETTER ORGANIZED...AND BOTH OBJECTIVE AND SUBJECTIVE DVORAK
 INTENSITY ESTIMATES HAVE INCREASED SINCE THIS MORNING.  THE
 OFFICIAL FORECAST IS INCREASED TO 60 KT AND NORBERT IS
 NEARING HURRICANE STRENGTH.  THE INTENSITY FORECAST AND THE
 ASSOCIATED REASONING ARE UNCHANGED FROM THE EARLIER PACKAGE. 
 NORBERT IS EXPECTED TO BE WITHIN A FAVORABLE ENVIRONMENT FOR
 STRENGTHENING AND ALL OF THE AVAILABLE GUIDANCE CALLS FOR THE
 CYCLONE TO REACH AT LEAST CATEGORY ONE INTENSITY IN A COUPLE OF
 DAYS.  THE HWRF REMAINS SOMEWHAT OF AN OUTLIER...ALBEIT A LITTLE
 WEAKER THAN BEFORE...AND SHOWS NORBERT BECOMING A MAJOR HURRICANE. 
 THE REMAINING INTENSITY MODELS ARE LOWER...AND A CONSENSUS OF THESE
 MODELS IS THE BASIS FOR THE OFFICIAL FORECAST.   BY DAYS 4 AND
 5...NORBERT IS FORECAST TO BE APPROACHING COOLER WATERS AND A MORE
 STABLE AIR MASS.  THEREFORE...SOME WEAKENING IS SHOWN BEYOND 72
 HOURS.  HOWEVER...MUCH UNCERTAINTY REMAINS IN THE TRACK
 FORECAST...ESPECIALLY IN TERMS OF FORWARD SPEED...AT THESE
 EXTENDED RANGES AND NORBERT COULD REACH LESS FAVORABLE CONDITIONS
 SOONER OR LATER THAN SHOWN HERE.  
  
 NORBERT CONTINUES ON A GENERAL WESTWARD TO WEST-NORTHWESTWARD
 HEADING OR 290/7. THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR
 THE NEXT 2 DAYS AS A MID-LEVEL RIDGE REMAINS TO THE NORTH. 
 THEREAFTER...A LARGE TROUGH IS FORECAST TO DIG SOUTHWARD ALONG THE
 WEST COAST OF THE UNITED STATES WHICH SHOULD RESULT IN A NORTHWARD
 TURN IN 3-4 DAYS.  THERE ARE STILL SOME DIFFERENCES AMONG THE
 VARIOUS TRACK MODELS BEYOND 72 HOURS AND THE MODELS HAVE NOT
 DEMONSTRATED GOOD RUN-TO-RUN CONSISTENCY.  THE GFS REMAINS THE
 SOUTHERN OUTLIER AND NEVER GETS NORBERT FAR ENOUGH NORTH TO RESPOND
 TO THE TROUGH.  CONVERSELY...THE UKMET AND NOGAPS SHOW NORBERT
 ACCELERATING NORTH-NORTHEASTWARD AHEAD OF THE TROUGH.  THE OFFICIAL
 FORECAST IS AGAIN SHIFTED A LITTLE SOUTH EARLY IN THE FORECAST
 PERIOD AND WEST LATE IN THE FORECAST PERIOD.  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      06/2100Z 14.5N 105.3W    60 KT
  12HR VT     07/0600Z 14.7N 106.3W    65 KT
  24HR VT     07/1800Z 15.1N 107.7W    70 KT
  36HR VT     08/0600Z 15.7N 109.0W    75 KT
  48HR VT     08/1800Z 16.5N 110.4W    80 KT
  72HR VT     09/1800Z 18.5N 112.5W    80 KT
  96HR VT     10/1800Z 21.0N 113.5W    75 KT
 120HR VT     11/1800Z 24.0N 112.5W    60 KT
  
 $$
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