000 WTPZ45 KNHC 161438 TCDEP5 HURRICANE RICK DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP202009 800 AM PDT FRI OCT 16 2009 RICK IS RAPIDLY SPINNING UP THIS MORNING AS A CURVED BAND OF DEEP CONVECTION HAS WRAPPED COMPLETELY AROUND THE CENTER. BASED UPON THIS STRUCTURE...THE DVORAK ESTIMATES CAME IN FROM SAB AND TAFB AT T3.5 AND 4.0...RESPECTIVELY. BECAUSE OF CONTINUED DEVELOPMENT SINCE THE SYNOPTIC TIME...THE INITIAL INTENSITY IS SET AT 65 KT...MAKING RICK THE 7TH HURRICANE OF THE EASTERN NORTH PACIFIC HURRICANE SEASON. RICK IS MOVING 280/08...WHILE LOCATED SOUTHEAST OF A STRONG DEEP-LAYERED RIDGE. THIS SHOULD BE THE PRIMARY FEATURE TO CONTINUE STEERING RICK TOWARD THE WEST OR WEST-NORTHWEST OVER THE NEXT THREE DAYS. AT THE LONGER RANGES...THE MODELS DIVERGE IN WHETHER RICK WILL CONTINUE AS A STRAIGHT-MOVER...SLOW SUBSTANTIALLY...OR RECURVE TOWARD BAJA CALIFORNIA. THE REGIONAL HURRICANE MODELS...GFDL AND HWRF...ARE CALLING FOR THE LATTER SCENARIO...BUT THEY APPEAR TO BE BREAKING THE RIDGE DOWN UNREALISTICALLY. THE OFFICIAL FORECAST IS SHIFTED TO THE LEFT...SOUTHWESTWARD...OF THE PREVIOUS NHC PREDICTION...BUT IS CLOSE TO THE MODEL CONSENSUS WHICH HAS ALSO SHIFTED SOME TO THE LEFT. RICK IS EMBEDDED WITHIN A VERY LOW VERTICAL SHEAR ENVIRONMENT WITH ABUNDANT LOWER TROPOSPHERIC MOISTURE AS DEPICTED BY THE TOTAL PRECIPITABLE WATER IMAGERY AND THE SHIPS ANALYSIS OF RELATIVE HUMIDITY. RICK IS ALSO TRAVERSING OVER VERY WARM...30C...WATERS. THE RAPID INTENSIFICATION INDEX CONTINUES TO INDICATE A HIGH CHANCE...74%...OF 30 KT OF INTENSIFICATION IN THE NEXT 24 HOURS. THIS IS THE BASIS FOR BRINGING RICK'S WINDS TO 90 KT TOMORROW MORNING. THERE DOES NOT APPEAR TO BE ANY INHIBITING FACTORS FOR CONTINUED DEVELOPMENT THROUGH THE NEXT TWO OR THREE DAYS AND THE INTENSITY FORECAST SHOWS RICK PEAKING AS A CATEGORY FOUR HURRICANE. AT THE LONGER RANGES...THE SSTS ENCOUNTERED BY RICK SHOULD COOL SOME WHILE THE VERTICAL SHEAR SHOULD INCREASE SOME. WEAKENING TO A CATEGORY TWO HURRICANE IS THUS INDICATED BY DAY 5. THE INTENSITY PREDICTION IS CLOSEST TO THE SHIPS MODEL AND IS SIMILAR TO THE PREVIOUS OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 16/1500Z 12.7N 99.4W 65 KT 12HR VT 17/0000Z 12.9N 100.5W 75 KT 24HR VT 17/1200Z 13.3N 102.4W 90 KT 36HR VT 18/0000Z 13.7N 104.6W 100 KT 48HR VT 18/1200Z 14.3N 106.9W 115 KT 72HR VT 19/1200Z 15.5N 111.0W 115 KT 96HR VT 20/1200Z 17.0N 113.0W 105 KT 120HR VT 21/1200Z 19.0N 113.5W 90 KT $$ FORECASTER LANDSEA/BEVEN