000 WTPZ44 KNHC 210233 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010 800 PM PDT SUN JUN 20 2010 SATELLITE IMAGERY INDICATES THAT CELIA HAS CONTINUED TO INTENSIFY BASED ON DATA T-NUMBERS OF T4.5/77 KT USING AN EMBEDDED CENTER PATTERN. A 21/0007Z SSMIS OVERPASS INDICATED A NEARLY CLOSED EYEWALL IN THE MID- AND LOW-LEVELS...AND AN INTERMITTENT CLOUD-FILLED EYE HAS BEEN NOTED IN VISIBLE IMAGERY DURING THE PAST 6 HOURS. BASED ON THIS INFORMATION...THE INTENSITY IS CONSERVATIVELY INCREASED TO 70 KT FOR THIS ADVISORY. THE INITIAL MOTION ESTIMATE IS 270/06. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK REASONINGS OVER THE PAST 24 HOURS. CELIA IS BEING STEERED IN A GENERAL WESTWARD DIRECTION BY AN EAST-WEST ORIENTED SUBTROPICAL RIDGE TO THE NORTH OF THE HURRICANE. THIS DEEP-LAYER FLOW REGIME IS EXPECTED TO REMAIN INTACT THROUGH 96 HOURS...AFTER WHICH AN UPPER-LEVEL TROUGH DIGGING SOUTHWARD OFF THE U.S. WEST COAST IS FORECAST TO ERODE THE RIDGE AND ALLOW CELIA TO GRADUALLY TURN WEST-NORTHWESTWARD BY DAY 5. THE OFFICIAL FORECAST IS CLOSE TO THE CONSENSUS OF THE TIGHTLY PACKED DYNAMICAL MODELS... EXCLUDING THE GFS WHICH CONTINUES TO BE A SOUTHERLY OUTLIER. WATER VAPOR AND VISIBLE SATELLITE IMAGERY INDICATE CIRRUS STREAMERS FROM A LARGE DISSIPATING THUNDERSTORM COMPLEX LOCATED EAST OF CELIA BEGINNING TO UNDERCUT THE HURRICANE OUTFLOW LAYER. AS A RESULT... SOME MID- TO UPPER-LEVEL WIND SHEAR SHOULD BEGIN TO DISRUPT THE HURRICANE SOON...POSSIBLY EVEN HALTING THE INTENSIFICATION PROCESS. BY 24 HOURS...HOWEVER...THE GFS-BASED SHIPS INTENSITY MODEL AND THE OTHER DYNAMICAL MODELS ARE FORECASTING THE VERTICAL WIND SHEAR TO DECREASE TO LESS THAN 10 KT...WHICH SHOULD PRODUCE AN OUTFLOW ENVIRONMENT CONDUCIVE FOR AT LEAST MODEST STRENGTHENING TO RESUME. THE WEAKENING TREND AT DAY 5 MAY BE PREMATURE IF CELIA DOES NOT REACH COOLER WATER AS CURRENTLY EXPECTED. THE OFFICIAL INTENSITY FORECAST IS IN CLOSE AGREEMENT WITH THE SHIPS MODEL...AND IS MARKEDLY HIGHER THAN BOTH THE GFDL AND HWRF MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 21/0300Z 11.6N 100.9W 70 KT 12HR VT 21/1200Z 11.5N 101.9W 75 KT 24HR VT 22/0000Z 11.5N 103.1W 80 KT 36HR VT 22/1200Z 11.6N 104.5W 90 KT 48HR VT 23/0000Z 11.8N 106.0W 100 KT 72HR VT 24/0000Z 12.6N 109.7W 105 KT 96HR VT 25/0000Z 13.8N 113.5W 105 KT 120HR VT 26/0000Z 15.5N 117.0W 95 KT $$ FORECASTER STEWART