Hurricane HILARY
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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
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