WTPA41 PHFO 191455
TCDCP1

TROPICAL STORM FERNANDA DISCUSSION NUMBER  16
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP062011
500 AM HST FRI AUG 19 2011

THE PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER...OR LLCC...OF
MINIMAL TROPICAL STORM FERNANDA IS EVIDENT IN INFRARED SATELLITE
IMAGERY EARLY THIS MORNING. PRIOR TO THE GOES11 ECLIPSE...THE
TROPICAL CYCLONE WAS COMPLETELY DEVOID OF DEEP CONVECTION FOR
SEVERAL HOURS. HOWEVER...AROUND 1100 UTC...A SINGLE THUNDERSTORM
DEVELOPED JUST WEST OF THE APPARENT LLCC. SINCE THAT TIME...THIS
CONVECTION HAS CONTINUED TO GROW IN AREAL COVERAGE AND INTENSITY...
WITH HIGHEST TOPS OF THE CUMULONIMBUS CLOUDS EXTENDING UP TO ABOUT
48 THOUSAND FEET. DESPITE THIS SMALL AREA OF THUNDERSTORMS...
FERNANDA CONTINUES TO STRUGGLE IN A HOSTILE ENVIRONMENT...WITH
VERTICAL WIND SHEAR OF ABOUT 14 KT FROM 170 DEGREES BASED ON THE
LATEST AVAILABLE UW/CIMSS ANALYSIS. THE TROPICAL STORM ALSO IS IN A
REGION OF LESS THAN FAVORABLE SSTS OF ABOUT 26 DEGREES C...AND VERY
LOW OCEAN HEAT CONTENT VALUES ACCORDING TO THE MOST RECENT CIRA
ANALYSIS.

THE LLCC OF FERNANDA IS MOVING 280/10. THE LATEST SATELLITE
INTENSITY ESTIMATES FROM CPHC...JTWC AND SAB WERE ALL 3.0. DUE TO
THE PROLONGED LOSS OF DEEP CONVECTION AND THE POOR APPEARANCE OF
THE TROPICAL CYCLONE IN SATELLITE IMAGERY....HAVE ASSIGNED A
CURRENT INTENSITY OF 35 KT. FERNANDA REMAINS SANDWICHED BETWEEN AN
UPPER LEVEL LOW TO ITS WEST...AND A BROAD UPPER LEVEL RIDGE TO ITS
EAST. THE GLOBAL FORECAST MODELS CONTINUE TO FORECAST THE UPPER LOW
AND RIDGE WILL MOVE WESTWARD IN TANDEM WITH FERNANDA...MAINTAINING
SUBSTANTIAL SOUTHERLY VERTICAL WIND SHEAR OVER THE SYSTEM THROUGH
THIS WEEKEND. THE SHIPS MODEL SHOWS THAT NOT ONLY WILL THE SHEAR
PERSIST...BUT IT WILL CONTINUE TO INCREASE WITH TIME. 
 
FERNANDA IS CURRENTLY MOVING TOWARD A WEAKNESS IN THE MID-LEVEL
RIDGE TO ITS NORTH. GLOBAL MODELS SHOW THIS RIDGE BUILDING WESTWARD
LATER TODAY AND SATURDAY...WHICH WILL TURN THE MUCH WEAKENED AND
SHALLOWER SYSTEM TOWARD THE WEST. WITH TIME...THE DEEP CONVECTION
WILL LIKELY BE SEPARATED FROM THE LLCC...AND THE LLCC WILL BE
STEERED BY THE LOW-LEVEL TRADE WINDS. THE OFFICIAL FORECAST TRACK
WAS SHIFTED SLIGHTLY TO LEFT OF THE PREVIOUS TRACK FORECAST...AND
LIES NEAR THE MIDDLE OF THE MODEL GUIDANCE ENVELOPE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/1500Z 15.1N 144.6W   35 KT  40 MPH
 12H  20/0000Z 15.5N 146.1W   30 KT  35 MPH
 24H  20/1200Z 15.9N 148.1W   25 KT  30 MPH
 36H  21/0000Z 16.2N 150.1W   25 KT  30 MPH
 48H  21/1200Z 16.3N 152.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  22/1200Z 16.5N 156.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER HOUSTON