WTPA41 PHFO 182102
TCDCP1

TROPICAL STORM FERNANDA DISCUSSION NUMBER  13
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP062011
1100 AM HST THU AUG 18 2011

FERNANDA APPEARS TO BE STARTING TO FEEL THE EFFECTS OF INCREASING
SOUTHEASTERLY SHEAR. SATELLITE DERIVED UPPER LEVEL WINDS IN THE
VICINITY OF THE CYCLONE ARE FROM THE SOUTHEAST AT 30 TO 40 KT...AND
THE SATELLITE IMAGERY DEPICTS AN INCREASINGLY ELONGATED AND
ASYMMETRIC SYSTEM. A COUPLE OF HELPFUL MICROWAVE PASSES EARLY THIS
MORNING INDICATE THAT FOR NOW...FERNANDA IS MAINTAINING A
WELL-ORGANIZED CORE AND THE CENTER FIXES LEND CREDENCE TO THE
INITIAL MOTION ESTIMATE OF 300/11.

SATELLITE INTENSITY ESTIMATES FROM CPHC AND JTWC WERE 3.5...WHILE
SAB HAD 4.0. THE CURRENT INTENSITY WILL BE MAINTAINED AT 55 KT.
FERNANDA HAS PROBABLY ALREADY PEAKED IN INTENSITY. FERNANDA IS
LOCATED BETWEEN AN UPPER LEVEL LOW ABOUT 600 MILES SOUTH SOUTHEAST
OF HAWAII...AND AN UPPER LEVEL RIDGE TO THE EAST OF FERNANDA. THE
GLOBAL MODELS FORECAST THE UPPER LOW TO MOVE WESTWARD IN TANDEM
WITH FERNANDA...MAINTAINING SOUTHERLY SHEAR OVER THE SYSTEM THROUGH
THE ENTIRE FORECAST PERIOD. IN ADDITION...FERNANDA WILL BE MOVING
OVER GRADUALLY COOLER WATER FOR THE FIRST 48 TO 60 HOURS. ALTHOUGH
SSTS WARM OVER THE FORECAST TRACK BEYOND 60 HOURS...BY THAT TIME
THE DEEP CONVECTION IS LIKELY TO BE WELL SEPARATED FROM THE LLCC.

FERNANDA IS CURRENTLY MOVING TOWARD A WEAKNESS IN THE MID LEVEL
RIDGE TO ITS NORTH. GLOBAL MODELS SHOW THE RIDGE REDEVELOPING
FRIDAY AND SATURDAY...WHICH SHOULD HELP TO STEER FERNANDA ON A MORE
WESTWARD COURSE. IN ADDITION...AS THE DEEP CONVECTION SEPARATES
FROM THE LLCC...THE LLCC WILL BE STEERED BY THE LOW LEVEL TRADE
WIND FLOW. THE OFFICIAL FORECAST TRACK REMAINS CLOSE TO THE
PREVIOUS TRACK AND LIES ALONG THE SOUTHERN EDGE OF THE MODEL
ENVELOPE...IN BEST AGREEMENT WITH THE GFS AND ECMWF MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  18/2100Z 14.6N 142.1W   55 KT  65 MPH
 12H  19/0600Z 15.4N 143.7W   50 KT  60 MPH
 24H  19/1800Z 16.2N 145.9W   50 KT  60 MPH
 36H  20/0600Z 16.7N 147.9W   45 KT  50 MPH
 48H  20/1800Z 17.1N 150.0W   40 KT  45 MPH
 72H  21/1800Z 17.4N 154.0W   30 KT  35 MPH
 96H  22/1800Z 17.3N 157.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  23/1800Z...DISSIPATED
 
$$
FORECASTER R BALLARD