000
WTPZ45 KNHC 070848
TCDEP5
HURRICANE NORBERT DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
200 AM PDT TUE OCT 07 2008
 
AFTER LOOKING A LITTLE RAGGED A FEW HOURS AGO...THE AREA OF DEEP
CONVECTION AND COLD CLOUD TOPS HAS CONSOLIDATED OVER THE CENTER
OF NORBERT.  HOWEVER...RECENT MICROWAVE IMAGERY HAS NOT DETECTED
AN EYE FEATURE.  SUBJECTIVE DVORAK INTENSITY ESTIMATES REMAIN 65 KT
FROM BOTH AGENCIES AND THE LATEST OBJECTIVE ESTIMATES ARE ONLY
SLIGHTLY HIGHER...THEREFORE THE INITIAL INTENSITY IS KEPT AT 65 KT.
SOUTHEASTERLY SHEAR IS ANTICIPATED TO BE LOW ENOUGH TO ALLOW
FOR MODEST STRENGTHENING DURING THE NEXT COUPLE OF DAYS.  THROUGH
72 HOURS...THE OFFICIAL INTENSITY FORECAST IS BETWEEN THE LOWER
STATISTICAL GUIDANCE AND THE MORE ROBUST DYNAMICAL GUIDANCE.
THEREAFTER...THE EXACT TRACK WILL MAKE A DIFFERENCE AS TO THE SSTS
THAT NORBERT CROSSES OVER.  THE CURRENT FORECAST KEEPS NORBERT OVER
27 DEGREE SSTS...SO ONLY A LITTLE WEAKENING IS INDICATED MAINLY DUE
TO AN INCREASE IN SOUTHWESTERLY SHEAR.
 
THE MICROWAVE IMAGES SUGGEST THAT NORBERT HAS TAKEN A SLIGHT JOG
TO THE RIGHT WITH AN INITIAL MOTION ESTIMATE OF 295/7.  A MID-LEVEL
RIDGE TO THE NORTHEAST OF THE HURRICANE IS FORECAST TO STEER IT
WEST-NORTHWESTWARD DURING THE NEXT COUPLE OF DAYS.  THEREAFTER...A
TROUGH APPROACHING THE WEST COAST OF THE UNITED STATES IS FORECAST
TO WEAKEN THE RIDGE...WHICH IS EXPECTED TO TURN NORBERT NORTHWARD
AT THAT TIME.  MOST OF THE TRACK GUIDANCE INDICATES THAT THE TROUGH
WILL BE DEEP ENOUGH TO PICK UP NORBERT AND TURN IT NORTHEASTWARD
TOWARD THE BAJA PENINSULA.  HOWEVER...THE ECMWF SHOWS THE TROUGH
BY-PASSING NORBERT...WHILE THE GFS PREDICTS A VERY UNLIKELY
INTERACTION BETWEEN THE HURRICANE AND THE DISTURBANCE CURRENTLY
OVER THE FAR EASTERN PACIFIC.  WHILE LOW WEIGHT HAS BEEN PLACED ON
THESE LATTER SOLUTIONS...THE REMAINDER OF THE GUIDANCE CONTINUES TO
HAVE SIGNIFICANT DIFFERENCES ON THE FORWARD SPEED ON NORBERT IN THE
3-5 DAY TIME FRAME.  THE UPDATED FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND IS IN BEST AGREEMENT WITH THE GFDL...WHICH
IS A LITTLE SLOWER THAN THE MODEL CONSENSUS AT DAYS 4 AND 5.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/0900Z 15.1N 106.4W    65 KT
 12HR VT     07/1800Z 15.5N 107.5W    70 KT
 24HR VT     08/0600Z 16.0N 109.0W    75 KT
 36HR VT     08/1800Z 16.6N 110.4W    80 KT
 48HR VT     09/0600Z 17.5N 111.6W    80 KT
 72HR VT     10/0600Z 19.8N 113.0W    80 KT
 96HR VT     11/0600Z 22.5N 112.5W    70 KT
120HR VT     12/0600Z 26.0N 110.0W    60 KT
 
$$
FORECASTER BROWN