WTPA41 PHFO 190901
TCDCP1

TROPICAL STORM FERNANDA DISCUSSION NUMBER  15
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP062011
1100 PM HST THU AUG 18 2011

FERNANDA IS FALLING APART...AS INDICATED BY THE DRAMATIC COLLAPSE OF
DEEP CONVECTION OVER THE LAST SIX HOURS. ALSO...THERE IS NO SIGN OF
ANY ADDITIONAL DEVELOPMENT OF THUNDERSTORMS. THE 15 TO 20 KT SOUTH
SOUTHEAST SHEAR...AS ESTIMATED BY CIMSS...IS DOING A GOOD JOB AT
SHREDDING APART FERNANDA. FERNANDA CONTINUES TO MOVE TO THE WEST
NORTHWEST AT 10 KT.
 
THE SATELLITE INTENSITY ESTIMATE FROM CPHC WAS 3.0...WHILE JTWC AND
SAB CAME IN WITH 2.5. WENT WITH AN INITIAL INTENSITY OF 45 KT...
WHICH IS PROBABLY TOO GENEROUS. FERNANDA IS SITUATED BETWEEN AN
UPPER LEVEL LOW CENTERED SOUTH SOUTHEAST OF HAWAII...AND AN UPPER
LEVEL RIDGE LOCATED EAST OF FERNANDA. GLOBAL MODELS FORECAST THE
UPPER LOW AND RIDGE TO MOVE TO THE WEST IN TANDEM WITH FERNANDA...
MAINTAINING A SUBSTANTIAL SOUTHERLY SHEAR OVER THE SYSTEM THROUGH
THE FORECAST PERIOD. THE SHIPS MODEL SHOWS THAT NOT ONLY WILL THE
SHEAR PERSIST BUT WILL GREATLY INCREASE WITH TIME. SSTS WILL BE OF
NO HELP AS WELL WITH COOLER TEMPERATURES AHEAD OF FERNANDA. BASED
ON ALL OF THE ABOVE...HAVE SPED UP FERNANDA/S DEMISE TO 48 HOURS.
THE INTENSITY FORECAST IS CLOSE TO DSHP. LOOKING AT THE MOST RECENT
SATELLITE IMAGES...THE SYSTEM MAY BECOME A POST-TROPICAL REMNANT
LOW IN 24 HOURS.
 
FERNANDA IS CURRENTLY MOVING TOWARD A WEAKNESS IN A MID LEVEL RIDGE
TO ITS NORTH. GLOBAL MODELS SHOW THE RIDGE BUILDING WESTWARD FRIDAY
AND SATURDAY...WHICH WILL TURN THE MUCH WEAKENED AND SHALLOWER
SYSTEM TO THE WEST. WITH TIME...THE DEEP CONVECTION...IF THERE IS
ANY LEFT...WILL BE SEPARATED FROM THE LLCC...AND THE LLCC WILL BE
STEERED BY THE LOW LEVEL TRADE WINDS. THE OFFICIAL FORECAST TRACK
REMAINS CLOSE TO THE PREVIOUS TRACK AND LIES IN THE CENTER OF A
TIGHT MODEL ENVELOPE. 
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  19/0900Z 15.3N 143.6W   45 KT  50 MPH
 12H  19/1800Z 15.8N 145.1W   35 KT  40 MPH
 24H  20/0600Z 16.3N 147.1W   30 KT  35 MPH
 36H  20/1800Z 16.7N 149.2W   25 KT  30 MPH
 48H  21/0600Z 17.0N 151.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  22/0600Z 17.2N 154.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  23/0600Z 17.4N 158.8W   15 KT  15 MPH...DISSIPATED
120H  24/0600Z 17.5N 163.0W   10 KT  10 MPH...DISSIPATED
 
$$
FORECASTER CRAIG