000 WTPZ44 KNHC 240240 TCDEP4 HURRICANE HILARY DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011 800 PM PDT FRI SEP 23 2011 THE CLOUD PATTERN ASSOCIATED WITH HILARY CONTINUES TO BE RATHER SPECTACULAR ON BOTH CONVENTIONAL SATELLITE IMAGERY AND MICROWAVE DATA. IT IS SMALL BUT VERY SYMMETRIC WITH A DISTINCT EYE SURROUNDED BY VERY STRONG CONVECTION. ALL SATELLITE INTENSITY ESTIMATES YIELD AN INITIAL INTENSITY OF 125 KNOTS. GIVEN THE EXTREMELY GOOD PREVAILING ENVIRONMENT FOR INTENSIFICATION...HILARY COULD STILL GAIN SOME STRENGTH DURING THE NEXT 24 HOURS. EVEN IF EYEWALL REPLACEMENT CYCLES OCCUR AND RESULT IN FLUCTUATIONS IN INTENSITY...HILARY IS FORECAST TO REMAIN AS A POWERFUL HURRICANE FOR THE NEXT TWO TO THREE DAYS. THEREAFTER...THE ENVIRONMENT BECOMES LESS CONDUCIVE...AND HILARY SHOULD BEGIN TO SLOWLY WEAKEN. TRACKING THE EYE ON SATELLITE GIVES AN INITIAL MOTION OF 280 DEGREES AT 8 KNOTS. THE STEERING PATTERN IN THE EASTERN PACIFIC IS NORMALLY VERY STEADY...AND THIS TIME IS NO DIFFERENT. THE SUBTROPICAL RIDGE TO THE NORTH WILL CONTINUE TO FORCE HILARY ON A GENERAL WEST OR WEST-NORTHWEST TRACK FOR THE NEXT 3 DAYS. THEREAFTER...THE HURRICANE WILL REACH A WEAKNESS IN THE RIDGE AND SHOULD BEGIN TO MOVE TOWARD THE NORTHWEST...AND EVEN NORTHWARD BUT VERY SLOWLY. TRACK GUIDANCE IS IN VERY GOOD AGREEMENT INITIALLY WHEN THE STEERING IS WELL ESTABLISHED. BEYOND 3 DAYS...THE GUIDANCE BECOMES REALLY DIVERGENT...BUT THE GENERAL TUNE IS FOR THE HURRICANE TO GAIN LATITUDE OR TO RECURVE. IT COULD BE AN INTERESTING BUT DIFFICULT FORECAST BEYOND FIVE DAYS. I AM GLAD I DO NOT HAVE TO MAKE IT AT THIS TIME. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 16.7N 104.0W 125 KT 145 MPH 12H 24/1200Z 16.9N 105.4W 130 KT 150 MPH 24H 25/0000Z 17.3N 107.3W 125 KT 145 MPH 36H 25/1200Z 17.5N 109.0W 120 KT 140 MPH 48H 26/0000Z 17.8N 110.7W 115 KT 135 MPH 72H 27/0000Z 18.0N 113.5W 110 KT 125 MPH 96H 28/0000Z 19.5N 115.5W 90 KT 105 MPH 120H 29/0000Z 21.0N 116.0W 75 KT 85 MPH $$ FORECASTER AVILA