Hurricane FRANK

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HURRICANE FRANK DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092010
200 PM PDT THU AUG 26 2010
 
FRANK APPEARS TO HAVE STRENGTHENED A LITTLE MORE TODAY. AN EYE HAS
OCCASIONALLY BEEN EVIDENT IN VISIBLE SATELLITE IMAGES AND THE
CENTRAL DENSE OVERCAST IS A LITTLE BETTER ORGANIZED THAN IT WAS
EARLIER. DVORAK T-NUMBERS ARE 77 KT FROM BOTH TAFB AND SAB. BASED
ON THESE ESTIMATES AND THE IMPROVED CLOUD PATTERN...THE INITIAL
INTENSITY IS INCREASED A BIT TO 80 KT.
 
THE HURRICANE HAS RESUMED A WEST-NORTHWESTWARD MOTION...290/9...AND
NOW LIES SLIGHTLY TO THE NORTH OF THE PREVIOUS FORECAST TRACK. A
WEST-NORTHWEST TO NORTHWEST MOTION IS EXPECTED OVER THE NEXT DAY OR
SO AS THE CYCLONE REMAINS STEERED BY A MID-LEVEL RIDGE TO ITS NORTH
AND NORTHEAST. THEREAFTER...A TURN TO THE NORTH-NORTHWEST AND THEN
NORTH IS FORECAST WITH A DECREASE IN FORWARD SPEED AS A DEEP LAYER
TROUGH STRENGTHENS NEAR THE UNITED STATES WEST COAST. THE NHC
OFFICIAL TRACK FORECAST IS ADJUSTED A LITTLE TO THE RIGHT OF THE
PREVIOUS ONE IN THE SHORT-TERM...TO ACCOUNT FOR THE INITIAL MOTION
AND POSITION...AND THEN A LITTLE TO THE LEFT AT THE END OF THE
FORECAST PERIOD TO COME INTO BETTER AGREEMENT WITH THE MODEL
GUIDANCE.

NONE OF THE INTENSITY MODELS SHOW ADDITIONAL STRENGTHENING AND IN
FACT...MOST HAVE A GRADUAL WEAKENING ALMOST IMMEDIATELY. THIS SEEMS
PLAUSIBLE GIVEN 15-20 KT OF EAST-NORTHEASTERLY SHEAR SHOWN BY THE
SHIPS MODEL AND COOLER WATERS ALONG THE FORECAST TRACK. FRANK IS
FORECAST TO MOVE OVER WATERS COOLER THAN 26 DEGREES C IN ABOUT 36
HOURS. THIS...COMBINED WITH A MORE STABLE ATMOSPHERIC ENVIRONMENT...
SHOULD CAUSE A MORE RAPID WEAKENING BEYOND THAT TIME AND IS
REFLECTED IN THE NHC FORECAST.  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/2100Z 18.1N 110.3W    80 KT
 12HR VT     27/0600Z 18.5N 111.5W    75 KT
 24HR VT     27/1800Z 19.0N 112.9W    70 KT
 36HR VT     28/0600Z 19.6N 113.8W    65 KT
 48HR VT     28/1800Z 20.3N 114.3W    55 KT
 72HR VT     29/1800Z 21.5N 114.5W    40 KT
 96HR VT     30/1800Z 22.5N 114.5W    30 KT...POST-TROP/REMNT LOW
120HR VT     31/1800Z 23.5N 114.5W    25 KT...POST-TROP/REMNT LOW
 
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FORECASTER CANGIALOSI
 
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