000 WTPZ45 KNHC 071434 TCDEP5 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