ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE HILARY DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011 200 AM PDT FRI SEP 23 2011 HILARY HAS CONTINUED TO INTENSIFY. THE SATELLITE APPEARANCE OF THE CYCLONE IS QUITE IMPRESSIVE...WITH THE HURRICANE MAINTAINING A WELL-DEFINED 10 N MI WIDE EYE AND A RATHER SYMMETRIC CENTRAL DENSE OVERCAST SURROUNDED BY A THICK RING OF VERY COLD CLOUD TOPS. DVORAK T-NUMBERS FROM TAFB AND SAB AT 0600 UTC WERE 6.5 AND SUPPORT AN INITIAL INTENSITY OF 125 KT. SOME ADDITIONAL STRENGTHENING IS POSSIBLE IN THE SHORT TERM AS HILARY REMAINS IN A NEARLY IDEAL ENVIRONMENT OF LIGHT SHEAR AND OVER VERY WARM WATERS. HOWEVER... EYEWALL REPLACEMENT CYCLES...WHICH ARE NEARLY IMPOSSIBLE TO TIME...ARE LIKELY TO INFLUENCE THE INTENSITY WITHIN A DAY OR SO. ONLY A SLOW DECREASE IN STRENGTH IS EXPECTED THROUGH THE REST OF THE FORECAST PERIOD AS WATERS ONLY GRADUALLY COOL AND THE SHEAR REMAINS FAIRLY LOW. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE AND IS IN VERY GOOD AGREEMENT WITH THE VARIOUS INTENSITY CONSENSUS AIDS. HILARY HAS JOGGED A BIT TO THE LEFT DURING THE LAST 6 HOURS...WITH THE LONGER-TERM MOTION ESTIMATE OF 280/10. THE RECENT CHANGE IN THE TRACK TOWARD THE WEST SEEMS TO BE IN RESPONSE TO THE HURRICANE MOVING UNDERNEATH A MID-LEVEL RIDGE EXTENDING FROM NORTHERN MEXICO WESTWARD INTO THE SUBTROPICAL EASTERN PACIFIC. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT THIS FEATURE WILL STEER HILARY ON A GENERAL WESTWARD TO WEST-NORTHWESTWARD COURSE FOR THE NEXT SEVERAL DAYS. THE OFFICIAL FORECAST HAS BEEN ADJUSTED A BIT TO THE SOUTH THROUGH 96 HOURS TO ACCOUNT FOR RECENT TRENDS AND ON THE ASSUMPTION OF A STRONGER RIDGE THROUGH THAT TIME...IN BEST AGREEMENT WITH THE RELIABLE GFS/ECWMF MODELS. TOWARD THE END OF THE PERIOD...THE MODEL GUIDANCE BEGINS TO DIVERGE DUE TO THE DEPICTION OF A SHORTWAVE TROUGH DIGGING SOUTHEASTWARD OVER THE SOUTHWESTERN UNITED STATES. THIS FEATURE COULD WEAKEN THE RIDGE ENOUGH TO CAUSE HILARY TO SLOW DOWN AND TURN MORE NORTHWEST OR PERHAPS EVEN NORTH. THE NHC FORECAST HAS BEEN SHIFTED A BIT TO THE RIGHT AT DAY 5 BUT REMAINS WELL LEFT OF THE MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 16.0N 101.9W 125 KT 145 MPH 12H 23/1800Z 16.2N 103.2W 130 KT 150 MPH 24H 24/0600Z 16.5N 104.8W 125 KT 145 MPH 36H 24/1800Z 16.9N 106.4W 115 KT 135 MPH 48H 25/0600Z 17.2N 107.9W 110 KT 125 MPH 72H 26/0600Z 17.9N 111.0W 100 KT 115 MPH 96H 27/0600Z 18.8N 113.7W 95 KT 110 MPH 120H 28/0600Z 20.5N 115.0W 85 KT 100 MPH $$ FORECASTER KIMBERLAIN NNNN
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Page last modified: Tuesday, 17-Jul-2012 13:44:16 UTC