Hurricane NORBERT

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HURRICANE NORBERT DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
800 AM PDT TUE OCT 07 2008
 
NORBERT'S CLOUD PATTERN HAS BECOME A LITTLE BETTER ORGANIZED OVER
THE PAST SEVERAL HOURS.  THERE IS A VERY COLD-TOPPED CDO FEATURE
AND EVIDENCE OF BANDING DEVELOPING OVER THE WESTERN SEMICIRCLE. 
THE CURRENT INTENSITY IS SET TO 70 KT WHICH IS BETWEEN DVORAK
ESTIMATES FROM TAFB AND SAB. NORBERT SHOULD REMAIN IN A
WEAK SHEAR...WARM WATER ENVIRONMENT FOR THE NEXT 2-3 DAYS SO
STRENGTHENING IS FORECAST...MORE OR LESS IN LINE WITH THE INTENSITY
MODEL CONSENSUS.  THE HWRF MODEL CONTINUES TO SHOW THE MOST
STRENGTHENING WITH THE SHIPS AND LGEM GUIDANCE BEING MUCH LOWER.
ONE OF THE INHIBITING FACTORS IN THE LATTER TWO STATISTICAL/
DYNAMICAL TECHNIQUES IS THE GFS VORTEX TENDENCY TERM...WHICH
COULD BE UNREALISTICALLY NEGATIVE SINCE THAT GLOBAL MODEL APPEARS
TO SPIN NORBERT DOWN TOO MUCH...AND SPIN UP A SYSTEM TO THE EAST OF
NORBERT TOO MUCH...IN THE NEXT SEVERAL DAYS.
 
THE INITIAL MOTION CONTINUES TOWARD THE WEST-NORTHWEST OR 290/7. 
OUR TRACK FORECAST REASONING HAS NOT CHANGED SIGNIFICANTLY SINCE
THE LAST ADVISORY PACKAGE.  MOST OF THE DYNAMICAL MODELS CONTINUE
TO SHOW NORBERT TURNING NORTHWARD INTO A WEAKNESS IN THE
SUBTROPICAL RIDGE...AND THEN MOVING NORTHEASTWARD LATE IN THE
FORECAST PERIOD IN RESPONSE TO A ROBUST MID-TROPOSPHERIC TROUGH
OVER THE SOUTHWESTERN UNITED STATES.  HOWEVER NOT ALL OF THE GLOBAL
MODELS CARRY NORBERT OVER THE BAJA CALIFORNIA PENINSULA.  FOR
EXAMPLE THE HIGHLY-REGARDED ECMWF MODEL DEPICTS THE TROUGH MISSING
NORBERT AND SHOWS THE TROPICAL CYCLONE WANDERING OFF TO THE WEST
NEAR THE END OF THE FORECAST PERIOD.  THE NHC TRACK FORECAST FOR
THIS ADVISORY IS VERY SIMILAR TO THE PREVIOUS ONE AND IS A LITTLE
SLOWER THAN THE DYNAMICAL MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/1500Z 15.3N 107.1W    70 KT
 12HR VT     08/0000Z 15.7N 108.2W    70 KT
 24HR VT     08/1200Z 16.3N 109.7W    75 KT
 36HR VT     09/0000Z 17.1N 111.2W    80 KT
 48HR VT     09/1200Z 18.0N 112.2W    80 KT
 72HR VT     10/1200Z 20.5N 113.4W    80 KT
 96HR VT     11/1200Z 23.5N 112.5W    70 KT
120HR VT     12/1200Z 26.0N 110.5W    60 KT
 
$$
FORECASTER PASCH
 
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