000 WTPZ41 KNHC 170237 TCDEP1 TROPICAL STORM FERNANDA DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP062011 800 PM PDT TUE AUG 16 2011 SATELLITE IMAGES SHOW THAT THE CLOUD PATTERN OF THE STORM REMAINS WELL ORGANIZED...WITH WELL-DEFINED CURVED BANDS. HOWEVER THE CLOUD TOPS HAVE WARMED SIGNIFICANTLY OVER THE PAST FEW HOURS...INDICATING A DECREASE IN THE INTENSITY OF THE DEEP CONVECTION. THIS DECREASE IS PROBABLY ASSOCIATED WITH A DIURNAL FLUCTUATION AND IS LIKELY ONLY TEMPORARY. SATELLITE INTENSITY ESTIMATES REMAIN 45 KT SO THE CURRENT WIND SPEED IS HELD AT THAT VALUE. FERNANDA CONTINUES TO EXHIBIT STRONG AND FAIRLY SYMMETRIC UPPER-LEVEL OUTFLOW... AND IS FORECAST TO REMAIN OVER WATERS WARMER THAN 26 DEG C FOR THE NEXT COUPLE OF DAYS. HENCE THE CYCLONE IS LIKELY TO STRENGTHEN AND THE OFFICIAL FORECAST SHOWS THE SYSTEM BECOMING A HURRICANE. THIS IS IN GOOD AGREEMENT WITH THE CONSENSUS OF THE NUMERICAL INTENSITY GUIDANCE. IN THE LATTER PART OF THE FORECAST PERIOD... SOUTH-SOUTHWESTERLY SHEAR ASSOCIATED WITH AN UPPER-TROPOSPHERIC TROUGH NEAR THE HAWAIIAN ISLANDS IS PREDICTED TO INCREASE TO NEAR 30 KT OVER FERNANDA. THEREFORE THE SYSTEM SHOULD WEAKEN RAPIDLY BY DAY 5 AND IS FORECAST TO BECOME A REMNANT LOW AROUND THAT TIME. BASED ON THE LATEST FIXES AN ADDITIONAL...SLIGHT...SOUTHWARD ADJUSTMENT TO THE TRACK HAS BEEN MADE. THE INITIAL MOTION IS WESTWARD NEAR 7 KT. NOT MUCH CHANGE HAS BEEN MADE TO THE PREVIOUS TRACK FORECAST OR REASONING. A WEAKNESS IN THE SUBTROPICAL RIDGE NEAR 140W LONGITUDE IS EXPECTED TO CAUSE THE CYCLONE TO TURN TOWARD THE WEST-NORTHWEST TOMORROW. THERE IS A FAIR AMOUNT OF SPREAD IN THE TRACK GUIDANCE...WITH THE HWRF AND GFDL MODELS LYING ON THE NORTHERN EDGE OF THE DYNAMICAL MODEL SUITE AND THE ECMWF AND UKMET NEAR THE SOUTHERN EDGE. THE OFFICIAL FORECAST IS ONLY A TAD SLOWER THAN THE PREVIOUS ONE AND JUST SOUTH OF THE MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 11.5N 136.2W 45 KT 50 MPH 12H 17/1200Z 11.7N 137.3W 50 KT 60 MPH 24H 18/0000Z 12.2N 138.6W 55 KT 65 MPH 36H 18/1200Z 12.9N 140.1W 60 KT 70 MPH 48H 19/0000Z 13.7N 141.8W 65 KT 75 MPH 72H 20/0000Z 15.5N 145.5W 55 KT 65 MPH 96H 21/0000Z 16.0N 149.5W 40 KT 45 MPH 120H 22/0000Z 16.0N 153.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER PASCH