000 WTPZ45 KNHC 310234 TCDEP5 TROPICAL STORM GIL DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP102007 800 PM PDT THU AUG 30 2007 CONVENTIONAL SATELLITE IMAGERY AND AN EARLIER AMSR-E MICROWAVE OVERPASS INDICATE THAT THE CENTER OF GIL REMAINS BENEATH THE NORTHEASTERN PORTION OF THE CONVECTIVE MASS...SUGGESTING THAT EASTERLY SHEAR IS STILL AFFECTING THE TROPICAL CYCLONE. ALTHOUGH DVORAK INTENSITY ESTIMATES ARE 35 KT FROM BOTH AGENCIES...THE MOST RECENT IMAGES SUGGEST THAT THE -80C CLOUD TOP CANOPY IS EXPANDING...PARTICULARLY OVER THE NORTHEAST QUADRANT. CONSEQUENTLY...THE INITIAL INTENSITY REMAINS AT 40 KT. IT IS A BIT OF A MYSTERY WHETHER OR NOT THE UNFAVORABLE THERMODYNAMIC ENVIRONMENT...INDICATIVE BY THE RATHER LARGE AREA OF STRATOCUMULUS JUST TO THE WEST OF THE CYCLONE...WILL OUTWEIGH THE EXPECTED DIMINISHING VERTICAL SHEAR OVER THE NEXT FEW DAYS. THE GFDL AND THE SHIPS MAINTAIN A 40 TO 50 KT SYSTEM THROUGH 96 HOURS...WHILE THE SUPER ENSEMBLE...ICON...AND THE LGEM INDICATE A GRADUAL WEAKENING TREND BEYOND 36 HOURS. THE LATTER INTENSITY MODELS SEEM MORE REASONABLE...ESPECIALLY SINCE GIL IS EXPECTED TO MOVE OVER COOLER WATERS IN 48 HOURS. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS PACKAGE...INDICATING LITTLE CHANGE DURING THE NEXT 36 HOURS...WITH A WEAKENING TREND TO A REMNANT LOW EXPECTED TOWARD THE END OF THE FORECAST PERIOD. THE INITIAL MOTION IS UNCHANGED FROM THE PREVIOUS ADVISORY...265/9...AS WELL AS THE TRACK FORECAST PHILOSOPHY. MID-TROPOSPHERIC RIDGE EXTENDING WEST-SOUTHWESTWARD FROM THE SOUTHWEST U.S. SHOULD STEER THE CYCLONE IN A GENERALLY WESTWARD MOTION DURING THE NEXT TWO DAYS. AFTERWARD...A TURN TO THE WEST-NORTHWEST IS EXPECTED AS GIL ROUNDS THE WESTERN PERIPHERY OF THE RIDGE. BEYOND 96 HOURS...AS GIL WEAKENS TO A REMNANT LOW OVER COOLER WATERS...THE LOW LAYER EASTERLIES SHOULD INDUCE A TURN BACK TO THE WEST. FORECAST POSITIONS AND MAX WINDS INITIAL 31/0300Z 19.1N 115.3W 40 KT 12HR VT 31/1200Z 18.9N 116.8W 40 KT 24HR VT 01/0000Z 18.9N 118.9W 40 KT 36HR VT 01/1200Z 18.9N 121.0W 40 KT 48HR VT 02/0000Z 19.2N 123.2W 35 KT 72HR VT 03/0000Z 19.9N 127.5W 35 KT 96HR VT 04/0000Z 20.5N 131.5W 25 KT...REMNANT LOW 120HR VT 05/0000Z 20.5N 135.5W 25 KT...REMNANT LOW $$ FORECASTER ROBERTS/BEVEN