498
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
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