000 WTPZ44 KNHC 251439 TCDEP4 HURRICANE HILARY DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011 800 AM PDT SUN SEP 25 2011 HILARY HAS BEEN MAINTAINING A FAIRLY WELL-DEFINED EYE ON INFRARED IMAGERY ALTHOUGH THE COVERAGE OF THE COLDEST CLOUD TOPS HAS DECREASED SLIGHTLY. ON VISIBLE IMAGES...THE EYE HAS BECOME SOMEWHAT OBSCURED BY MIDDLE OR LOW CLOUDS. DVORAK T-NUMBERS FROM TAFB AND SAB ARE UNCHANGED AND THE INITIAL INTENSITY IS HELD AT 110 KT. THE HURRICANE IS EXPECTED TO CONTINUE MOVING OVER WARM WATERS AND IN A LOW-SHEAR ATMOSPHERIC ENVIRONMENT FOR THE NEXT COUPLE OF DAYS...SO VERY LITTLE WEAKENING IS ANTICIPATED DURING THE NEXT 48 HOURS. SOME FLUCTUATIONS IN INTENSITY WILL PROBABLY OCCUR AS A RESULT OF INNER-CORE CHANGES SUCH AS EYEWALL REPLACEMENTS...HOWEVER THESE CHANGES ARE VERY DIFFICULT TO PREDICT. LATER IN THE FORECAST PERIOD...THE COMBINATION OF COOLER WATERS AND INCREASING SHEAR SHOULD CAUSE WEAKENING. THE OFFICIAL INTENSITY FORECAST FOLLOWS THE STATISTICAL-DYNAMICAL LGEM INTENSITY GUIDANCE RATHER CLOSELY. ASIDE FROM SOME WOBBLES...THE TRACK OF HILARY HAS BEEN WESTWARD OR 275/8. A CONTINUED WESTWARD TO WEST-NORTHWESTWARD MOTION IS EXPECTED OVER THE NEXT 48 HOURS OR SO...AS THE HURRICANE MOVES ALONG THE SOUTHERN SIDE OF A SUBTROPICAL RIDGE. A MID- TO UPPER-LEVEL LOW CURRENTLY NEAR 24N 135W IS PREDICTED TO MOVE EASTWARD AND BREAK DOWN THE RIDGE IN 3 TO 5 DAYS...AND MOST OF THE TRACK MODELS SHOW HILARY TURNING SHARPLY TOWARD THE NORTH IN THE LATTER PART OF THE FORECAST PERIOD. THE OFFICIAL TRACK FORECAST IS NOT MUCH DIFFERENT FROM THE PREVIOUS ONE...AND IS ALSO VERY SIMILAR TO THE MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 25/1500Z 17.2N 109.2W 110 KT 125 MPH 12H 26/0000Z 17.3N 110.5W 110 KT 125 MPH 24H 26/1200Z 17.4N 112.1W 105 KT 120 MPH 36H 27/0000Z 17.5N 113.8W 105 KT 120 MPH 48H 27/1200Z 17.9N 115.2W 100 KT 115 MPH 72H 28/1200Z 19.3N 116.1W 85 KT 100 MPH 96H 29/1200Z 21.5N 115.5W 65 KT 75 MPH 120H 30/1200Z 24.5N 115.5W 45 KT 50 MPH $$ FORECASTER PASCH