000 WTPZ41 KNHC 022031 TCDEP1 TROPICAL STORM HENRIETTE DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP112007 200 PM PDT SUN SEP 02 2007 VISIBLE SATELLITE IMAGERY INDICATES THAT HENRIETTE IS TRYING TO FORM A BANDING EYE. HOWEVER...DVORAK INTENSITY ESTIMATES REMAIN AT 55 KT AND THE INITIAL INTENSITY IS HELD AT 60 KT FOR THIS ADVISORY. HENRIETTE IS LOCATED IN A SEEMINGLY IDEAL ENVIRONMENT FOR STRENGTHENING...AND GLOBAL MODELS ALL AGREE THAT THE CYCLONE WILL REMAIN BENEATH A WELL-DEFINED UPPER-LEVEL ANTICYCLONE AND WITHIN A LOW SHEAR ENVIRONMENT. SSTS ARE EXPECTED TO BE SUFFICIENTLY WARM FOR THE NEXT DAY OR SO. DESPITE THIS ENVIRONMENT...THE INTENSITY FORECAST IS MUDDIED BY THE FACT THAT HENRIETTE IS A VERY SMALL CYCLONE CAPABLE OF RAPID INTENSITY FLUCTUATIONS...BOTH UP AND DOWN. MOREOVER...THE NEW OFFICIAL FORECAST TRACK IS A LITTLE CLOSER TO THE MAINLAND COAST OF MEXICO. SUCH A SMALL CYCLONE COULD UNDERGO RAPID INTENSIFICATION IF THE CENTER STAYS FAR ENOUGH OFFSHORE. LIKEWISE...IT COULD BE EASILY DISRUPTED BY INTERACTION WITH THE COAST OF MAINLAND MEXICO SHOULD IT MOVE A LITTLE RIGHT OF THE OFFICIAL FORECAST TRACK. THE OFFICIAL FORECAST ASSUMES HENRIETTE WILL REMAIN FAR ENOUGH OFFSHORE DURING THE FIRST 36 HOURS FOR INTENSIFICATION TO OCCUR. BEYOND 72 HOURS...HENRIETTE IS EXPECTED TO MOVE ACROSS THE BAJA PENINSULA INTO NORTHWESTERN MAINLAND MEXICO WHERE IT SHOULD DISSIPATE. MOISTURE FROM THIS SYSTEM COULD MAKE IT INTO PORTIONS OF THE SOUTHWESTERN UNITED STATES IN 4 OR 5 DAYS. VISIBLE IMAGERY INDICATES THAT HENRIETTE HAS BEEN MOVING SLOWER THAN PREVIOUSLY THOUGHT...WITH AN INITIAL MOTION ESTIMATED AT 295/4. THE OVERALL FORECAST PHILOSOPHY IS UNCHANGED. GLOBAL MODELS SHOW A MID-LEVEL RIDGE CURRENTLY OVER THE SOUTHWESTERN UNITED STATES SHIFTING EASTWARD OVER THE NEXT COUPLE OF DAYS AHEAD OF A LARGE MIDDLE- TO UPPER-LEVEL TROUGH APPROACHING THE WEST COAST OF THE UNITED STATES. THIS PATTERN SHOULD ALLOW HENRIETTE TO GRADUALLY TURN NORTHWESTWARD THEN NORTHWARD. IN GENERAL...MOST OF THE GUIDANCE HAS TRENDED EASTWARD WITH THE MOST SIGNIFICANT EASTWARD SHIFT BEING IN THE UKMET. THE GFDL REMAINS THE EASTERNMOST OUTLIER...BUT THIS SOLUTION CANNOT BE IGNORED GIVEN ITS PERFORMANCE LAST YEAR DURING JOHN AND LANE...TWO HURRICANES THAT SIMILARLY PARALLELED THE COAST OF MAINLAND MEXICO. THE OFFICIAL FORECAST IS AGAIN ADJUSTED A LITTLE TO THE RIGHT OF THE PREVIOUS ONE GIVEN THE RECENT MODEL TRENDS AND THE GFDL TRACK. HENRIETTE'S CURRENT SLOW MOTION DELAYS THE NEED FOR WATCHES OVER PORTIONS OF THE SOUTHERN BAJA PENINSULA...BUT THEY MAY BE REQUIRED LATER TODAY. FORECAST POSITIONS AND MAX WINDS INITIAL 02/2100Z 18.6N 106.6W 60 KT 12HR VT 03/0600Z 19.1N 107.4W 70 KT 24HR VT 03/1800Z 20.1N 108.6W 75 KT 36HR VT 04/0600Z 21.3N 109.7W 85 KT 48HR VT 04/1800Z 22.6N 110.6W 75 KT 72HR VT 05/1800Z 25.5N 111.5W 65 KT...INLAND OVER BAJA 96HR VT 06/1800Z 30.5N 111.5W 40 KT...INLAND 120HR VT 07/1800Z...DISSIPATED $$ FORECASTER RHOME