Hurricane FELICIA

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HURRICANE FELICIA DISCUSSION NUMBER  19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP082009
200 AM PDT SAT AUG 08 2009
 
INFRARED SATELLITE IMAGERY SUGGESTS THAT THE BRIEF INTENSIFICATION
OBSERVED EARLIER IS LIKELY NOW OVER...AND A GRADUAL...WEAKENING
SEEMS TO HAVE COMMENCED.  THIS IS EVIDENCED BY CLOUD TOP
TEMPERATURES THAT HAVE BEEN WARMING...AND A NOTABLE DRY SLOT THAT
HAS BEEN ROTATING NORTH OF THE CENTER. HOWEVER...FELICIA
HAS BEEN EXHIBITING MANY OF THE COMMON CHARACTERISTICS OF AN
ANNULAR HURRICANE...INCLUDING A FAIRLY UNIFORM RING OF DEEP
CONVECTION SURROUNDING THE CENTER AND A LACK OF DEEP CONVECTIVE
FEATURES OUTSIDE OF THIS AREA.  ON THE BASIS OF THE DEGRADED
SATELLITE APPEARANCE AND DVORAK CURRENT INTENSITY ESTIMATES OF 4.5
AND 5.0...THE INTENSITY IS LOWERED TO 80 KT THIS ADVISORY.
 
THE INITIAL MOTION ESTIMATE IS 285/12...BUT THE LAST FEW SATELLITE
PICTURES INDICATE THAT THE HEADING MAY ACTUALLY BE EVEN MORE
WESTWARD.  FELICIA IS IN THE PROCESS OF MAKING A GRADUAL TURN
TOWARD THE WEST IN RESPONSE TO A BUILDING MID-LEVEL RIDGE NORTH OF
THE CYCLONE...WHICH SHOULD CAUSE IT TO GAIN LITTLE LATITUDE BEYOND
24 HOURS. A WEAKER FELICIA LATER IN THE FORECAST SHOULD CONTINUE ON
A MOSTLY DUE-WESTWARD COURSE WITHIN THE TRADE WIND FLOW. OUTSIDE OF
THE GFS AND THE CANADIAN MODEL...WHICH SHOW A MORE NORTHERN
TRACK...THE DYNAMICAL MODEL GUIDANCE FAVORS THIS SCENARIO AND IS
FAIRLY TIGHTLY CLUSTERED ON A TRACK PASSING CLOSE TO THE ISLAND OF
HAWAII JUST AFTER 72 HOUR.  THE NEW FORECAST TRACK REPRESENTS AN
UPDATE OF THE PREVIOUS FORECAST AND LIES SLIGHTLY SOUTH OF THE
MODEL CONSENSUS IN AN EFFORT TO MINIMIZE THE CONTRIBUTION BY THE
GFS AND CANADIAN MODEL OUTPUT.
 
FELICIA HAS BEEN MOVING OVER COOLING SEA SURFACE TEMPERATURES DURING
THE LAST 24 HOURS...BUT WATER TEMPERATURES ARE PREDICTED TO SLOWLY
WARM ALONG THE FORECAST TRACK.  HOWEVER...WESTERLY VERTICAL WIND
SHEAR SHOULD ABRUPTLY INCREASE AROUND 48 HOURS IN ASSOCIATION WITH A
CLOSED MID- TO UPPER-LEVEL CYCLONE NORTH OF THE HAWAIIAN ISLANDS. 
ALL INTENSITY GUIDANCE CALLS FOR A GRADUAL WEAKENING OVER THE NEXT
DAY OR TWO...FOLLOWED BY AN ACCELERATED WEAKENING IN RESPONSE TO
THE INCREASING WESTERLY SHEAR.  SHOULD FELICIA ASSUME A MOTION
SOUTH OF THE FORECAST TRACK...IT WOULD LIKELY ENCOUNTER A LOWER
SHEAR ENVIRONMENT AND BE STRONGER THAN FORECAST.  ON THE OTHER
HAND...A MOTION NORTH OF THE FORECAST TRACK WOULD LEAD FELICIA INTO
EVEN HIGHER SHEAR AND WOULD RESULT IN A FASTER WEAKENING.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0900Z 19.0N 139.3W    80 KT
 12HR VT     08/1800Z 19.3N 141.2W    70 KT
 24HR VT     09/0600Z 19.5N 143.8W    65 KT
 36HR VT     09/1800Z 19.6N 146.4W    55 KT
 48HR VT     10/0600Z 19.5N 149.0W    50 KT
 72HR VT     11/0600Z 19.5N 154.5W    35 KT
 96HR VT     12/0600Z 19.5N 159.5W    30 KT
120HR VT     13/0600Z 20.0N 165.0W    25 KT...REMNANT LOW
 
$$
FORECASTER KIMBERLAIN/AVILA
 
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