000 WTPZ44 KNHC 292031 TCDEP4 TROPICAL STORM JULIETTE DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP142007 200 PM PDT SAT SEP 29 2007 VISIBLE IMAGERY INDICATES THAT THE LOW-LEVEL CENTER OF THE TROPICAL CYCLONE IS EMBEDDED JUST WITHIN THE EDGE OF A SOLID CONVECTIVE CLUSTER. DVORAK T-NUMBERS HAVE BEEN 2.5 FROM TAFB AND SAB FOR TWO CYCLES NOW...AND WITH A CLEARER KNOWLEDGE OF WHERE THE LOW-LEVEL CENTER IS IN RELATION TO THE DEEP CONVECTION...THE DEPRESSION IS BEING UPGRADED TO TROPICAL STORM JULIETTE. SEVERAL MICROWAVE PASSES THROUGHOUT THE MORNING...AS WELL AS CONFIRMATION FROM VISIBLE IMAGERY...INDICATE THAT THE LOW-LEVEL CENTER IS SLIGHTLY FARTHER NORTH THAN PREVIOUSLY ESTIMATED. THEREFORE...JULIETTE HAS BEEN MOVING IN A NORTHWESTERLY DIRECTION WITH AN INITIAL MOTION OF 310/10. IN THE SHORT-TERM...THE CYCLONE WILL CONTINUE THIS GENERAL MOTION AROUND THE PERIPHERY OF A MID-LEVEL RIDGE LOCATED OVER NORTHERN MEXICO. AFTER ABOUT 36-48 HOURS...JULIETTE IS EXPECTED TO WEAKEN AND WILL LIKELY TAKE A WESTWARD TURN WITH A DECREASE IN FORWARD SPEED AS IT BECOMES STEERED BY THE LOWER-LEVEL FLOW OF THE SUBTROPICAL RIDGE. THIS SCENARIO FOLLOWS THE SOLUTIONS PROVIDED BY THE GFS...GFDL...AND HWRF MODELS. JULIETTE IS IN THE PROCESS OF A SLOW AND GRADUAL STRENGTHENING WHICH SHOULD ONLY LAST ABOUT 36 HOURS OR SO. THEREAFTER...VERTICAL SHEAR WILL INCREASE FROM THE SOUTHEAST AND THE CYCLONE WILL MOVE INTO A MORE STABLE ENVIRONMENT LOCATED TO ITS NORTHWEST. IN ADDITION...THE LATEST FORECAST TRACK TAKES JULIETTE OVER A TONGUE OF COOLER WATERS THAT DEVELOPED BETWEEN SOCORRO AND CLARION ISLANDS WITHIN THE PAST WEEK. ONCE THESE FACTORS COME INTO PLAY...JULIETTE IS EXPECTED TO WEAKEN RATHER RAPIDLY TO A REMNANT LOW BY DAY 4 THEN DISSIPATE BY DAY 5. IF SOME OF THE DYNAMICAL MODELS HAVE THEIR WAY...JULIETTE COULD MEET HER LESS-THAN-SHAKESPEAREAN DEMISE SOONER THAN INDICATED IN THE OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 29/2100Z 16.5N 112.1W 35 KT 12HR VT 30/0600Z 17.7N 113.0W 40 KT 24HR VT 30/1800Z 19.4N 114.0W 45 KT 36HR VT 01/0600Z 20.9N 115.1W 45 KT 48HR VT 01/1800Z 21.5N 116.0W 40 KT 72HR VT 02/1800Z 21.7N 117.0W 30 KT 96HR VT 03/1800Z 21.7N 118.0W 25 KT...REMNANT LOW 120HR VT 04/1800Z...DISSIPATED $$ FORECASTER BERG/AVILA