000 WTPZ45 KNHC 211450 TCDEP5 TROPICAL STORM KIKO DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007 800 AM PDT SUN OCT 21 2007 EVEN THOUGH VERTICAL SHEAR IS NOT CURRENTLY ANALYZED TO BE THAT STRONG...AN EARLIER TRMM PASS SUGGESTS THE LOW-LEVEL CENTER IS BECOMING SEPARATED FROM THE MID-LEVEL CENTER. MOREOVER...CLOUD TOP TEMPERATURES HAVE BEEN STEADILY WARMING...AND LIGHTENING DATA SUGGEST A WEAKENING OF CORE CONVECTION. IT APPEARS THAT KIKO MAY HAVE PEAKED AND IS NOW BEGINNING TO WEAKEN. DVORAK INTENSITY ESTIMATES ARE UNCHANGED BUT A RECENT QUIKSCAT PASS SUGGESTS THAT THE WINDS HAVE DECREASED. THE CURRENT INTENSITY IS SET AT 50 KT AND THIS MAY BE GENEROUS. GIVEN THE PRESENT APPEARANCE IN SATELLITE IMAGERY AND THE INCREASINGLY HOSTILE ENVIRONMENT ALONG THE FORECAST TRACK...IT APPEARS THAT KIKO WILL NOT BECOME A HURRICANE AND THE OFFICIAL FORECAST NOW CALLS FOR GRADUAL WEAKENING. KIKO IS DRIFTING NORTH-NORTHWESTWARD...330/2...WITHIN A BREAK IN THE SUBTROPICAL RIDGE CREATED BY A DEEP-LAYERED TROUGH OVER THE WESTERN UNITED STATES. THE TROUGH IS EXPECTED TO GRADUALLY SHIFT EASTWARD ALLOWING A RIDGE TO BUILD TO THE NORTH OF KIKO AND FORCING A TURN TOWARDS THE WEST OR NORTHWEST. THE GFDL IS THE ONLY DYNAMICAL MODEL WHICH DOES NOT SHOW THIS WESTWARD TURN MATERIALIZING WITHIN THE FIRST 24 HOURS. INSTEAD...THE GFDL MAINTAINS A STRONG AND VERTICALLY ALIGNED VORTEX THAT CONTINUES NORTHWARD TOWARD THE SOUTHERN TIP OF THE BAJA PENINSULA. SINCE WEAKENING HAS ALREADY COMMENCED...THE GFDL IS CONSIDERED AN OUTLIER AND THE OFFICIAL FORECAST SHOWS A WESTWARD TURN BEGINNING LATER TODAY. NONETHELESS...INTERESTS ALONG THE WEST-CENTRAL COAST OF MAINLAND MEXICO AND THE SOUTHERN BAJA PENINSULA SHOULD CONTINUE TO MONITOR THE PROGRESS OF THE KIKO OVER THE NEXT DAY OR SO. FORECAST POSITIONS AND MAX WINDS INITIAL 21/1500Z 19.3N 107.4W 50 KT 12HR VT 22/0000Z 19.7N 107.8W 50 KT 24HR VT 22/1200Z 20.1N 108.8W 45 KT 36HR VT 23/0000Z 20.6N 110.2W 40 KT 48HR VT 23/1200Z 21.1N 112.0W 35 KT 72HR VT 24/1200Z 22.0N 115.5W 30 KT 96HR VT 25/1200Z 23.5N 119.0W 25 KT...REMNANT LOW 120HR VT 26/1200Z 24.5N 123.0W 20 KT...REMNANT LOW $$ FORECASTER RHOME