000 WTPZ44 KNHC 281434 TCDEP4 HURRICANE HILARY DISCUSSION NUMBER 30 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011 800 AM PDT WED SEP 28 2011 DEEP CONVECTION CONTINUES TO PULSE NEAR THE CENTER OF HILARY...AND RECENT MICROWAVE IMAGERY SHOWS THAT THE EYEWALL IS OPEN ON THE WEST SIDE. DVORAK ESTIMATES HAVE CONTINUED TO GRADUALLY DECREASE AND THE INITIAL INTENSITY OF 70 KT IS BASED ON A BLEND OF THE FINAL-T NUMBERS FROM TAFB AND SAB. HILARY SHOULD CONTINUE TO WEAKEN STEADILY AS THE CYCLONE CROSSES THE 26C ISOTHERM LATER TODAY AND THE VERTICAL SHEAR INCREASES TO NEAR 30 KT BY 24 HOURS. THE SHEAR SHOULD RESULT IN THE MID-LEVEL CIRCULATION OF HILARY SHEARING OFF AND THE LOW-LEVEL CIRCULATION BECOMING A REMNANT LOW BY 72 HOURS... WITH DISSIPATION EXPECTED BY DAY 5. THE NEW NHC INTENSITY FORECAST FOLLOWS A BLEND OF THE SHIPS AND LGEM. THE INITIAL MOTION ESTIMATE IS 320/6...AS HILARY CONTINUES TO TURN POLEWARD INTO A WEAKNESS IN THE SUBTROPICAL RIDGE. A MID-LEVEL LOW IS CURRENTLY MOVING SOUTHWARD ALONG 128W TOWARD HILARY...AND THIS SHOULD CONTINUE TO DRAW THE CYCLONE NORTHWARD UNTIL IT SHEARS APART. AFTER 72 HOURS THE REMNANT LOW SHOULD TURN BACK TOWARD THE WEST AS IT IS STEERED BY THE LOW-LEVEL RIDGING. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO AND HAS SHIFTED WESTWARD FOR THIS CYCLE. THE NHC FORECAST IS ADJUSTED WESTWARD TOWARD THE NEW MULTI-MODEL CONSENSUS THROUGH 72 HOURS...AND SHOWS A WESTWARD MOTION AT 96 HOURS FOLLOWING THE TREND OF THE GLOBAL MODELS. A NOAA AIRCRAFT WILL BE CONDUCTING A RESEARCH MISSION INTO HILARY LATER TODAY AND PROVIDE VALUABLE INFORMATION ON THE STRUCTURE AND INTENSITY HILARY. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 18.4N 118.4W 70 KT 80 MPH 12H 29/0000Z 19.2N 118.7W 65 KT 75 MPH 24H 29/1200Z 20.4N 119.1W 55 KT 65 MPH 36H 30/0000Z 21.5N 119.4W 40 KT 45 MPH 48H 30/1200Z 22.6N 119.8W 30 KT 35 MPH 72H 01/1200Z 24.5N 121.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 02/1200Z 24.5N 122.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 03/1200Z...DISSIPATED $$ FORECASTER BRENNAN