250
WTPZ45 KNHC 202033
TCDEP5
TROPICAL STORM KIKO DISCUSSION NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152007
200 PM PDT SAT OCT 20 2007
KIKO IS ALMOST TO HURRICANE STRENGTH. SATELLITE IMAGERY SHOWS A
WELL-DEFINED BANDING PATTERN AROUND THE CENTER...ALTHOUGH WITH
RATHER WARM CLOUD TOPS AT THE MOMENT. WHILE THERE WAS A HINT OF AN
EYE FORMING EARLIER...THAT HAS NOW BEEN FILLED BY NEW CONVECTION
NEAR THE CENTER. SATELLITE INTENSITY ESTIMATES ARE 65 KT FROM TAFB
AND 55 KT FROM SAB. THE INITIAL INTENSITY IS INCREASED TO 60 KT.
THE CIRRUS OUTFLOW IS GOOD TO THE NORTH AND SOUTH...AND POOR
ELSEWHERE.
THE INITIAL MOTION IS NOW 310/5. WHILE KIKO IS CURRENTLY BEING
STEERED BY A WEAK MID-LEVEL RIDGE OVER NORTHERN MEXICO...WATER
VAPOR IMAGERY SHOWS A DEVELOPING DEEP-LAYER TROUGH OVER THE WESTERN
UNITED STATES THAT SHOULD BREAK THAT RIDGE IN THE NEXT 12-24 HR.
THE LARGE-SCALE MODELS ARE NOW IN GOOD AGREEMENT THAT THE TROUGH
WILL AMPLIFY FAR ENOUGH TO THE EAST TO ALLOW A TRAILING RIDGE TO
BUILD NORTH OF KIKO...CAUSING THE STORM TO GRADUALLY TURN
WEST-NORTHWESTWARD AFTER 24 HR. DESPITE THIS IMPROVED AGREEMENT...
THE TRACK GUIDANCE SHOWS A NOTABLE SPREAD. THE GFS AND ECMWF SHOW
A WESTWARD MOTION NEAR OR SOUTH OF 20N...WHILE THE GFDL AND HWRF
FORECAST A TRACK JUST SOUTH OF THE SOUTHERN TIP OF BAJA CALIFORNIA.
THE NEW FORECAST TRACK IS A LITTLE TO THE NORTH OF THE PREVIOUS
TRACK AND THE MODEL CONSENSUS DURING THE FIRST 36 HR...AND THEN A
LITTLE SOUTH OF THEM THEREAFTER. THERE IS STILL A POSSIBLE
ALTERNATE SCENARIO OF A NORTHWARD TURN IN THE NEXT 12-24 HR AS THE
TROUGH APPROACHES FOLLOWED BY A SHARPER TURN TOWARD THE WEST AS THE
RIDGE BUILDS. CONSIDERABLE UNCERTAINTY REMAINS IN HOW CLOSE KIKO
MAY COME TO BAJA CALIFORNIA...SO INTERESTS THERE SHOULD CONTINUE TO
MONITOR THE PROGRESS OF THE STORM.
KIKO IS IN AN AREA OF LIGHT VERTICAL WIND SHEAR...AND THAT IS LIKELY
TO CONTINUE FOR 24-36 HR. ALL GUIDANCE FORECASTS STRENGTHENING
DURING THAT TIME...AND THE INTENSITY FORECAST NOW CALLS FOR KIKO TO
PEAK AT 75 KT IN 24 HR. AFTER THAT TIME...INCREASING SHEAR...DRY
AIR SEEN IN WATER VAPOR IMAGERY WEST OF KIKO...AND COOLING SEA
SURFACE TEMPERATURES ALONG THE FORECAST TRACK SHOULD CAUSE
WEAKENING. THE SSTS ARE BELOW 24C ALONG THE FORECAST TRACK WEST OF
110W...SO KIKO IS FORECAST TO BE DISSIPATING BY 120 HR.
FORECAST POSITIONS AND MAX WINDS
INITIAL 20/2100Z 18.5N 106.9W 60 KT
12HR VT 21/0600Z 19.2N 107.4W 70 KT
24HR VT 21/1800Z 19.9N 107.9W 75 KT
36HR VT 22/0600Z 20.4N 108.6W 75 KT
48HR VT 22/1800Z 20.8N 109.7W 70 KT
72HR VT 23/1800Z 21.5N 113.0W 60 KT
96HR VT 24/1800Z 22.0N 117.0W 40 KT
120HR VT 25/1800Z 22.5N 121.0W 25 KT...DISSIPATING
FORECASTER BEVEN
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