000 WTPZ45 KNHC 190900 TCDEP5 TROPICAL STORM KIKO DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007 200 AM PDT FRI OCT 19 2007 A QUIKSCAT OVERPASS BACK AT 0041Z SUGGESTED THAT THE MAXIMUM WINDS WERE STILL ABOUT 35 KT. SINCE THAT TIME THE CONVECTIVE PATTERN HAS BEEN INCONSISTENT...ALTHOUGH THE MOST RECENT FEW IMAGES SHOW A FAIRLY HEALTHY BURST IN THE SOUTHWESTERN QUADRANT. DESPITE 06Z SUBJECTIVE DVORAK ESTIMATES OF 45 KT...THE ADVISORY INTENSITY REMAINS 35 KT FOR NOW BASED ON THE EARLIER QUIKSCAT DATA...WHICH WERE ALSO USED TO CONTRACT THE 34-KT WIND RADII. CONDITIONS APPEAR RIPE FOR STRENGTHENING...HOWEVER...AS KIKO WILL SOON FIND ITSELF RIGHT BENEATH AN UPPER-LEVEL ANTICYCLONE AND STILL OVER VERY WARM WATERS JUST OFF THE PACIFIC COAST OF MEXICO. AS IN THE PREVIOUS ADVISORY...THE OFFICIAL FORECAST CALLS FOR KIKO TO BECOME A HURRICANE IN A COUPLE OF DAYS...WHICH IS A LITTLE ABOVE MOST OF THE OBJECTIVE GUIDANCE. THE FORECAST PEAK INTENSITY AT LONGER RANGES HAS BEEN REDUCED SLIGHTLY IN ACCORDANCE WITH THE GUIDANCE THAT SEEMS TO RESPOND TO A MODEST INCREASE IN SHEAR AND EVENTUALLY COOLER SSTS ON DAYS 4 AND 5. CENTER FIXES DERIVED FROM AN ANALYSIS OF THE QUIKSCAT AMBIGUITIES AND AN SSMIS IMAGE AT 0317Z...COMBINED WITH RECENT GOES INFRARED IMAGERY...DO NOT REVEAL MUCH MOTION OF THE CIRCULATION CENTER BUT HINT AT A NORTHWESTWARD DRIFT...AND THE INITIAL MOTION ESTIMATE REMAINS AN UNCERTAIN 315/3. THE MODELS GENERALLY FORECAST A NORTHWESTWARD MOTION ROUGHLY PARALLEL TO THE PACIFIC COAST OF MEXICO FOR 2-3 DAYS...BUT WITH DIFFERENCES PRIMARILY IN THE FORWARD SPEED...AS THE CYCLONE HEADS TOWARD A PERSISTENT BREAK IN THE SUBTROPICAL RIDGE OVER NORTHWESTERN MEXICO AND THE ADJACENT EASTERN PACIFIC. BEYOND 72 HOURS...MOST OF THE MODELS FORECAST A TURN TOWARD THE WEST AS A RIDGE BUILDS TO THE NORTH OF KIKO AS A DEEP-LAYER CYCLONE PROGRESSES EASTWARD ACROSS THE SOUTHERN UNITED STATES. THE LATITUDE AT WHICH THAT TURN OCCURS VARIES WILDLY AMONG THE MODELS...WITH THE GFDL FARTHEST NORTH NEAR THE SOUTHERN BAJA CALIFORNIA PENINSULA AND THE GFS ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE. THE NEW OFFICIAL FORECAST IS ROUGHLY DOWN THE MIDDLE OF THE MODEL SOLUTIONS AND JUST A LITTLE FASTER THAN THE PREVIOUS ADVISORY AT LONG RANGES. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 16.7N 104.9W 35 KT 12HR VT 19/1800Z 17.0N 105.3W 40 KT 24HR VT 20/0600Z 17.5N 105.9W 50 KT 36HR VT 20/1800Z 18.1N 106.6W 55 KT 48HR VT 21/0600Z 18.7N 107.3W 65 KT 72HR VT 22/0600Z 20.0N 108.5W 70 KT 96HR VT 23/0600Z 21.0N 110.5W 70 KT 120HR VT 24/0600Z 21.5N 113.0W 65 KT $$ FORECASTER KNABB