000 WTPZ45 KNHC 171447 TCDEP5 TROPICAL STORM KIKO DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007 800 AM PDT WED OCT 17 2007 THE LOW-LEVEL CENTER OF KIKO IS VERY HARD TO FIND THIS MORNING. FIRST-LIGHT VISIBLE IMAGES ALONG WITH RECENT AMSU AND QUIKSCAT DATA SHOW THE CIRCULATION IS ELONGATED EAST-NORTHEAST TO WEST-SOUTHWEST. THE ADVISORY POSITION IS AT THE WESTERN END OF THE ELONGATION NEAR THE CONVECTIVE OVERCAST...ALTHOUGH THE VISIBLE IMAGERY AND QUIKSCAT HINT THAT THE ACTUAL CENTER MAY BE FARTHER TO THE EAST. SATELLITE INTENSITY ESTIMATES ARE 35 TO 45 KT FROM TAFB AND SAB. THE QUIKSCAT DATA...WHILE HAVING RAIN CONTAMINATION PROBLEMS...SUGGESTS AN INTENSITY OF AT LEAST 35 KT. THE INITIAL INTENSITY WILL BE KEPT AT 35 KT. THE INITIAL MOTION IS A HIGHLY UNCERTAIN 045/4. KIKO IS SOUTH OF A BREAK IN THE MID-LEVEL SUBTROPICAL RIDGE CAUSED BY A STRONG DEEP-LAYER TROUGH OVER THE CENTRAL UNITED STATES. THE LARGE-SCALE MODELS AGREE ON FORECASTING A MID-LEVEL RIDGE TO BUILD OVER NORTHERN MEXICO BY 72 HR AS THE U.S. TROUGH MOVES EASTWARD. THIS SHOULD ALLOW KIKO TO MOVE SLOWLY NORTHWARD AND THEN NORTHWESTWARD. AFTER 72 HR...THE MEXICAN RIDGE WEAKENS AGAIN AS A SECOND DEEP-LAYER TROUGH MOVES INTO THE CENTRAL UNITED STATES. THE MODELS ARE NOT IN GOOD AGREEMENT ON WHAT THE SECOND TROUGH WILL DO TO KIKO. THE ECMWF HAS A DEEP ENOUGH TROUGH TO CAUSE KIKO TO MAKE LANDFALL IN MAINLAND MEXICO...WHILE THE GFS...THE BAM MODELS...AND THE FSU SUPERENSEMBLE SHOW KIKO MOVING WESTWARD SOUTH OF THE RIDGE. THE UKMET AND NOGAPS CALL FOR A SLOW NORTHWARD TO NORTH- NORTHWESTWARD MOTION AFTER 72 HR. THE NEW FORECAST TRACK IS NUDGED A LITTLE TO THE EAST OF THE PREVIOUS TRACK AND IS SLIGHTLY FASTER. IT IS IN BEST AGREEMENT WITH THE UKMET. KIKO CONTINUES UNDER ABOUT 20 KT OF EASTERLY VERTICAL WIND SHEAR. THE LARGE-SCALE MODELS FORECAST THE SHEAR TO DECREASE AFTER 24 HR...WITH GENERALLY FAVORABLE UPPER-LEVEL WINDS FORECAST BEYOND THAT TIME. THIS SHOULD ALLOW SOME STRENGTHENING...AND THE SHIPS...GFDL...AND HWRF ALL FORECAST KIKO TO REACH 55-60 KT BY 120 HR. THE NEW INTENSITY FORECAST CALLS FOR A SLIGHTLY HIGHER INTENSITY THAN THE PREVIOUS FORECAST IN AGREEMENT WITH THE SHIPS MODEL. SOME RE-LOCATION OF THE CENTER...AND CHANGES IN THE FORECAST TRACK...MAY BE NECESSARY ON THE NEXT ADVISORY. FORECAST POSITIONS AND MAX WINDS INITIAL 17/1500Z 14.8N 106.9W 35 KT 12HR VT 18/0000Z 15.2N 106.7W 35 KT 24HR VT 18/1200Z 15.7N 106.6W 35 KT 36HR VT 19/0000Z 16.1N 106.6W 40 KT 48HR VT 19/1200Z 16.7N 106.7W 45 KT 72HR VT 20/1200Z 17.5N 107.0W 50 KT 96HR VT 21/1200Z 18.5N 108.0W 55 KT 120HR VT 22/1200Z 19.5N 108.5W 55 KT $$ FORECASTER BEVEN