000 WTPZ45 KNHC 072033 TCDEP5 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