000 WTPZ45 KNHC 180233 TCDEP5 TROPICAL STORM KIKO DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007 800 PM PDT WED OCT 17 2007 NEW THUNDERSTORM CLUSTERS HAVE FIRED NEAR THE CENTER OF KIKO AFTER IT WAS EXPOSED FOR A FEW HOURS THIS AFTERNOON. HOWEVER...THIS SYSTEM STILL HAS A RATHER ELONGATED SHAPE AND IT IS UNKNOWN HOW SEPARATE THE TROPICAL CYCLONE IS FROM THE ITCZ. THERE HAVE BEEN NO CHANGES TO THE SATELLITE CLASSIFICATIONS...AND THE INITIAL INTENSITY WILL REMAIN 35 KT. GLOBAL MODELS SUGGEST THAT THE MODERATE TO STRONG EASTERLY SHEAR THAT HAS BEEN AFFECTING THIS SYSTEM WILL ABATE IN A DAY OR TWO WHICH...ASSUMING THE SYSTEM SURVIVES...WOULD ALLOW FOR SOME STRENGTHENING. IN FACT THE SHIPS/HWRF/GFDL MODELS SHOW THIS SYSTEM BECOMING A HURRICANE BY THE END OF THE FORECAST PERIOD. GIVEN THE DISHEVELED PATTERN ON SATELLITE...I WOULD PREFER TO WAIT UNTIL THE STORM SHOWS MORE SIGNS OF ORGANIZATION BEFORE JUMPING ON THE HURRICANE KIKO BANDWAGON. HOWEVER THE OFFICIAL FORECAST IS NUDGED UPWARDS AT DAYS 3-5 IN DEFERENCE TO OUR BEST INTENSITY GUIDANCE. THE INITIAL MOTION ESTIMATE IS 070/7...WHICH INDICATES A SMALL TURN TOWARD THE LEFT IN THE LAST SIX HOURS. KIKO APPEARS TO BE CAUGHT UP IN LOW-LEVEL WEST TO SOUTHWESTERLY FLOW ASSOCIATED WITH THE ITCZ. THIS PATTERN IS NOT EXPECTED TO LAST FOR MORE THAN A DAY OR SO DUE TO A BUILDING MIDDLE-LEVEL RIDGE OVER MEXICO. THIS RIDGE SHOULD FORCE THE STORM TO TURN LEFTWARD WITH TIME AND CAUSE A MORE NORTHWESTWARD MOTION IN A COUPLE DAYS. HOWEVER...THE BIG QUESTION IS WHETHER THE STORM WILL BE TOO CLOSE BY THEN TO MISS MEXICO. MOST MODELS HAVE SHIFTED EASTWARD COMPARED TO SIX HOURS AGO... ESPECIALLY THE 18Z UKMET MODEL RUN. THE ECMWF/GFDN/NOGAPS/UKMET MODELS ALL SHOW THE SYSTEM MOVING OVER OR CLOSE TO MEXICO DURING THE FORECAST PERIOD. THE OFFICIAL FORECAST IS A BLEND OF THOSE GLOBAL MODELS AND THE PREVIOUS ADVISORY...SHOWING SOME THREAT TO MEXICO IN A COUPLE OF DAYS. WATCHES MAY HAVE TO BE ISSUED TOMORROW...PARTICULARLY IF THIS EASTWARD SHIFT IN THE MODEL GUIDANCE CONTINUES. FORECAST POSITIONS AND MAX WINDS INITIAL 18/0300Z 14.8N 104.7W 35 KT 12HR VT 18/1200Z 15.2N 104.1W 35 KT 24HR VT 19/0000Z 16.0N 103.8W 35 KT 36HR VT 19/1200Z 16.8N 103.9W 40 KT 48HR VT 20/0000Z 17.4N 104.4W 45 KT 72HR VT 21/0000Z 18.5N 105.5W 55 KT 96HR VT 22/0000Z 19.0N 106.0W 60 KT 120HR VT 23/0000Z 20.0N 107.0W 60 KT $$ FORECASTER BLAKE