534
WTPZ45 KNHC 181457
TCDEP5
TROPICAL STORM KIKO DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007
800 AM PDT THU OCT 18 2007
SATELLITE IMAGERY THIS MORNING SHOWS THAT KIKO IS A LITTLE BETTER
ORGANIZED THAN 24 HR AGO...WITH A LESS ELONGATED LOW-LEVEL
CIRCULATION. EASTERLY VERTICAL WIND SHEAR HAS DECREASED OVER THE
PAST 24 HR...WHICH HAS ALLOWED THE CENTER TO BECOME MORE INVOLVED
WITH THE CONVECTION. HOWEVER...THE SYSTEM STILL APPEARS SOMEWHAT
RAGGED...AND BASED ON THIS AND UNCHANGED SATELLITE INTENSITY
ESTIMATES THE INITIAL INTENSITY REMAINS 35 KT.
THE CENTER OF KIKO MOVED FASTER DURING THE NIGHT...AND THE INITIAL
MOTION ESTIMATE IS 040/8. ALL GUIDANCE AGREES THAT THE FORWARD
SPEED SHOULD SLOW DURING THE NEXT 24-48 HR AS PRESSURES RISE OVER
NORTHERN MEXICO IN THE WAKE OF THE EASTWARD-MOVING DEEP-LAYER TROUGH
OVER THE UNITED STATES...ACCOMPANIED BY THE CENTER TURNING TO THE
NORTH AND NORTHWEST NEAR OR OVER THE PACIFIC COAST OF MEXICO.
AFTER 48 HR...A SECOND DEEP-LAYER TROUGH DEVELOPS OVER THE CENTRAL
AND WESTERN U.S. THE LARGE-SCALE MODELS CONTINUE TO DISAGREE ON
THE EVOLUTION OF THIS TROUGH AND ITS EFFECTS ON KIKO. THE ECMWF
AND NOGAPS FORECAST THE TROUGH TO AMPLIFY FARTHER TO THE WEST...
WITH KIKO TURNING NORTHWARD INTO MAINLAND MEXICO. THE UKMET AND
GFS FORECAST THE TROUGH TO AMPLIFY FARTHER TO THE EAST...WITH
RIDGING BUILDING NORTH OF KIKO CAUSING A WESTWARD TRACK INTO THE
OPEN PACIFIC. RIGHT NOW...IT CANNOT BE DETERMINED WHICH OF THESE
EXTREMES WILL BE RIGHT...SO THE FORECAST TRACK WILL COMPROMISE
BETWEEN THEM WITH A CONTINUED SLOW MOTION TOWARD THE NORTHWEST.
UPPER-LEVEL WINDS HAVE BECOME MORE FAVORABLE FOR DEVELOPMENT...WITH
THE LARGE-SCALE MODELS FORECASTING THEM TO REMAIN FAVORABLE FOR AT
LEAST THE NEXT 48-72 HR. THIS SHOULD ALLOW STRENGTHENING...WITH
THE MAIN NEGATIVE FACTOR BEING THE PROXIMITY TO LAND. THE NEW
INTENSITY FORECAST CALLS FOR FASTER INTENSIFICATION THEN THE
PREVIOUS FORECAST...WITH KIKO REACHING A 55 KT INTENSITY BEFORE THE
CENTER BRUSHES THE COAST OF MEXICO IN ABOUT 72 HR. KIKO COULD
BECOME A HURRICANE IF THE CENTER STAYS FARTHER OFFSHORE...AS
INDICATED BY THE GFDL MODEL.
THE CURRENT POSITION AND NEW FORECAST TRACK REQUIRE WARNINGS AND
WATCHES FOR PORTIONS OF THE COAST OF MEXICO AT THIS TIME.
FORECAST POSITIONS AND MAX WINDS
INITIAL 18/1500Z 16.4N 103.4W 35 KT
12HR VT 19/0000Z 17.0N 103.2W 35 KT
24HR VT 19/1200Z 17.5N 103.2W 40 KT
36HR VT 20/0000Z 18.0N 103.5W 45 KT
48HR VT 20/1200Z 18.5N 104.2W 50 KT
72HR VT 21/1200Z 19.5N 105.0W 55 KT...INLAND
96HR VT 22/1200Z 20.5N 106.0W 55 KT...OVER WATER
120HR VT 23/1200Z 22.0N 107.5W 60 KT
FORECASTER BEVEN
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