000 WTPZ41 KNHC 021441 TCDEP1 TROPICAL STORM HENRIETTE DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP112007 800 AM PDT SUN SEP 02 2007 WHILE DVORAK INTENSITY ESTIMATES WERE UNCHANGED AT 1200 UTC...DEEP CONVECTION NEAR THE CENTER HAS SINCE INCREASED AND A NEW BAND IS FORMING TO THE NORTH. RECENT MICROWAVE DATA ALSO SHOW THAT THE CYCLONE HAS A SMALL CORE. HENRIETTE COULD BE ON THE VERGE OF BECOMING A HURRICANE BUT I PREFER TO WAIT UNTIL VISIBLE IMAGERY CONFIRMS THE CENTER LOCATION AND STRUCTURE. ACCORDINGLY...THE INITIAL INTENSITY WILL REMAIN AT 60 KT FOR THIS ADVISORY. ALL INDICATIONS ARE THAT HENRIETTE WILL BE LOCATED IN A SEEMINGLY IDEAL ENVIRONMENT FOR STRENGTHENING DURING THE NEXT 36-48 HOURS. UPPER-LEVEL OUTFLOW IS ALREADY UNRESTRICTED IN ALL QUADRANTS AND GLOBAL MODELS SHOW THE ANTICYCLONE CURRENTLY OVER HENRIETTE BECOMING BETTER DEFINED DURING THE NEW FEW DAYS. ADDITIONALLY... SSTS ARE EXPECTED TO BE AMPLY WARM. THE SHIPS RAPID INTENSIFICATION INDEX INDICATES A HIGHER THAN USUAL CHANCE FOR RAPID INTENSIFICATION. THE OFFICIAL INTENSITY FORECAST IS NUDGED UPWARDS AND IS A LITTLE HIGHER THAN ICON. BEYOND 48 HOURS... COOLERS WATERS AND POSSIBLE INTERACTION WITH LAND ARE EXPECTED TO RESULT IN WEAKENING. HENRIETTE HAS BEEN MOVING A LITTLE TO THE RIGHT OF THE PREVIOUS FORECAST TRACK...WITH AN INITIAL MOTION ESTIMATED AT 295/6. THE SYNOPTIC STEERING PATTERN CONSISTS PRIMARILY OF A MID-TROPOSPHERIC RIDGE CURRENTLY OVER THE SOUTHWESTERN UNITED STATES. GLOBAL MODELS SHOW THIS RIDGE GRADUALLY SHIFTING EASTWARD OVER THE NEXT COUPLE OF DAYS AS A LARGE MIDDLE TO UPPER LEVEL TROUGH APPROACHES THE WEST COAST OF THE UNITED STATES. THIS WOULD ALLOW HENRIETTE TO GRADUALLY TURN NORTHWESTWARD THEN NORTHWARD. CONVERSELY...THE GFDL SHOWS A SLIGHTLY WEAKER RIDGE DURING THE FIRST COUPLE OF DAYS ALLOWING THE CYCLONE TO MOVE NORTHWARD ALMOST INSTANTLY AND THEN TURN NORTHEAST AS THE TROUGH REACHES THE WEST COAST OF THE U.S. WHILE THE GFDL REMAINS THE EASTERNMOST OUTLIER...IT SHOULD BE NOTED THAT THIS MODEL PERFORMED VERY WELL IN SIMILAR SITUATIONS LAST YEAR. IN PARTICULAR...THE GFDL MODEL OUTPERFORMED THE GLOBAL MODELS DURING JOHN AND LANE...TWO HURRICANES WHICH SIMILARLY PARALLELED THE COAST OF MAINLAND MEXICO. THE OFFICIAL FORECAST IS ADJUSTED A LITTLE TO THE RIGHT OF THE PREVIOUS ONE IN DEFERENCE TO THE GFDL MODEL AND IS A LITTLE EAST OF THE DYNAMICAL MODEL CONSENSUS. A TROPICAL STORM WATCH MAY BE REQUIRED FOR PORTIONS OF THE SOUTHERN BAJA PENINSULA LATER TODAY. FORECAST POSITIONS AND MAX WINDS INITIAL 02/1500Z 18.8N 106.7W 60 KT 12HR VT 03/0000Z 19.2N 107.6W 70 KT 24HR VT 03/1200Z 20.0N 109.0W 75 KT 36HR VT 04/0000Z 21.0N 110.2W 85 KT 48HR VT 04/1200Z 22.0N 111.3W 80 KT 72HR VT 05/1200Z 24.0N 112.5W 70 KT 96HR VT 06/1200Z 27.0N 113.0W 50 KT...INLAND OVER BAJA 120HR VT 07/1200Z 30.1N 113.0W 30 KT $$ FORECASTER RHOME