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Hurricane NORBERT


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HURRICANE NORBERT DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
200 PM PDT TUE OCT 07 2008

NORBERT CONTINUES TO STRENGTHEN AS SUGGESTED BY THE INCREASED
ORGANIZATION OF THE CLOUD PATTERN AND THE HINTS OF AN EYE ON
VISIBLE IMAGES.  AN SSMIS IMAGE FROM 1513 UTC SHOWED A BANDING-
TYPE...PARTIALLY-CLOSED...EYE.  CURRENT INTENSITY IS SET AT 75 KT
IN ACCORDANCE WITH THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB. 
CIRRUS OUTFLOW IS BECOMING WELL-DEFINED OVER MOST OF THE
CIRCULATION.  CONTINUED STRENGTHENING IS LIKELY AS THE HURRICANE
SHOULD REMAIN IN A WARM WATER AND LOW VERTICAL SHEAR ENVIRONMENT
FOR THE NEAR FUTURE.  MOST OF THE NUMERICAL GUIDANCE CALLS FOR
STRENGTHENING WITH THE HWRF AND GFDL MODELS BEING THE MOST
AGGRESSIVE.  ALSO...THE SHIPS MODEL NOW SHOWS MORE INTENSIFICATION
THAN EARLIER RUNS.  THE OFFICIAL INTENSITY FORECAST CONSERVATIVELY
BRINGS NORBERT TO CATEGORY TWO STATUS...BUT IT IS CERTAINLY
POSSIBLE FOR THIS SYSTEM TO BECOME A MAJOR HURRICANE.  LATE IN THE
FORECAST PERIOD... INCREASING SOUTH-SOUTHWESTERLY SHEAR SHOULD
INDUCE WEAKENING.

NORBERT HAS MOVED A LITTLE MORE WESTWARD OVER THE PAST SEVERAL HOURS
AND THE INITIAL MOTION IS NEAR 285/8.  THE TRACK FORECAST
PHILOSOPHY REMAINS BASICALLY THE SAME.  IN 2-3 DAYS...NORBERT IS
PREDICTED TO TURN NORTHWARD INTO A BREAK IN THE SUBTROPICAL RIDGE. 
AFTERWARDS...THE TROPICAL CYCLONE IS LIKELY TO TURN
NORTH-NORTHEASTWARD UNDER THE INFLUENCE OF A VIGOROUS 500 MB TROUGH
THAT DROPS INTO THE SOUTHWESTERN UNITED STATES.  AS WAS THE CASE ON
THE PREVIOUS FORECAST CYCLE...NOT ALL OF THE DYNAMICAL MODELS BRING
NORBERT NORTH-NORTHEASTWARD ACROSS BAJA CALIFORNIA.  NOTABLY...THE
GFS WEAKENS NORBERT CONSIDERABLY SO THAT IT DOES NOT RESPOND TO THE
MID-TROPOSPHERIC STEERING...RESULTING IN THE SYSTEM BEING ENTRAINED
SOUTHWARD INTO THE LOWER-TROPOSPHERIC CIRCULATION OF A
STRENGTHENING CYCLONE TO THE EAST OF NORBERT.  WHETHER OR NOT THE
EASTERN SYSTEM ENDS UP DEVELOPING...THE WEAKENING OF NORBERT
DEPICTED BY THE GFS SEEMS UNREALISTIC.  THEREFORE THE OFFICIAL
FORECAST TRACK IS CLOSE TO A SELECTIVE CONSENSUS OF DYNAMICAL
MODELS THAT EXCLUDES THE GFS IN THIS CASE.  THIS REPRESENTS ONLY A
SLIGHT WESTWARD SHIFT OF THE PREVIOUS OFFICIAL FORECAST TRACK.

IT IS PREMATURE TO SAY WHAT KIND OF IMPACT NORBERT MAY HAVE ON BAJA
CALIFORNIA.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/2100Z 15.2N 108.1W    75 KT
 12HR VT     08/0600Z 15.5N 109.4W    80 KT
 24HR VT     08/1800Z 16.1N 110.9W    85 KT
 36HR VT     09/0600Z 17.0N 112.1W    90 KT
 48HR VT     09/1800Z 18.0N 113.1W    90 KT
 72HR VT     10/1800Z 21.0N 113.7W    85 KT
 96HR VT     11/1800Z 24.5N 112.0W    75 KT...ON COAST
120HR VT     12/1800Z 28.0N 110.0W    60 KT...INLAND
 
$$
FORECASTER PASCH
 
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