000
WTPZ44 KNHC 220858
TCDEP4
 
TROPICAL STORM HILARY DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092011
200 AM PDT THU SEP 22 2011
 
RADAR DATA FROM PUERTO ANGEL MEXICO...MICROWAVE PASSES...AND
CONVENTIONAL SATELLITE IMAGERY SHOW THAT THE INNER CORE STRUCTURE
OF HILARY CONTINUES TO QUICKLY IMPROVE WITH AN EYE FEATURE NOTED. 
OBJECTIVE AND SUBJECTIVE DVORAK T-NUMBERS HAVE INCREASED TO AROUND
T3.5...HOWEVER GIVEN THE CONTINUED IMPROVEMENT IN ORGANIZATION...
THE INITIAL INTENSITY IS RAISED TO 60 KT.  HILARY IS FORECAST TO
REMAIN IN A LOW SHEAR ENVIRONMENT AND MOVE OVER SOME OF THE WARMEST
WATER IN THE EASTERN PACIFIC BASIN DURING THE NEXT COUPLE OF DAYS. 
AS A RESULT...CONTINUED STRENGTHENING IS EXPECTED AND A PERIOD OF
RAPID STRENGTHENING IS LIKELY AS LONG AS THE CORE REMAINS OFFSHORE. 
THE OFFICIAL FORECAST IS AT THE UPPER END OF THE GUIDANCE AND
PREDICTS HILARY TO BECOME A MAJOR HURRICANE WITHIN A COUPLE OF
DAYS.
 
THE INITIAL MOTION ESTIMATE IS 295/8 KT.  A MID- TO UPPER-LEVEL
RIDGE TO THE NORTH AND NORTHWEST OF HILARY IS FORECAST TO BUILD
DURING THE NEXT FEW DAYS.  AS THIS OCCURS...THE CYCLONE SHOULD
MOVE WEST-NORTHWESTWARD PARALLEL TO THE SOUTHERN COAST OF MEXICO.
LATE IN THE FORECAST PERIOD...THE RIDGE IS FORECAST TO WEAKEN AS
A TROUGH MOVES SOUTHEASTWARD INTO THE SOUTHWESTERN UNITED STATES.
THE GFDL AND HWRF MODELS...WHICH SHOW HILARY CLOSER TO THE COAST OF
MEXICO DURING THE NEXT COUPLE DAYS...TURN HILARY NORTHWARD AHEAD
OF THE TROUGH INTO SOUTHWESTERN MEXICO.  ON THE OTHER HAND...THE
UKMET...GFS...NOGAPS...AND ECMWF...WHICH ALL SHOW A MORE SOUTHERN
TRACK INITIALLY...KEEP HILARY ON A SLOWER WEST-NORTHWESTWARD
MOTION AT LEAST THROUGH 120 HOURS.  GIVEN THE NORTHWARD BIAS OF
THE GFDL/HWRF IN THE EASTERN PACIFIC THIS SEASON...THE OFFICIAL
FORECAST LEANS TOWARD THE LATTER SOLUTION KEEPING HILARY MOVING
MORE WESTWARD.  HOWEVER...THE UPDATED TRACK IS SLOWER THAN THE
PREVIOUS ADVISORY AT DAYS 4 AND 5 SINCE HILARY SHOULD DECELERATE 
AS THE RIDGE WEAKENS.


FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 14.7N  98.1W   60 KT  70 MPH
 12H  22/1800Z 15.2N  99.3W   70 KT  80 MPH
 24H  23/0600Z 15.9N 101.0W   85 KT 100 MPH
 36H  23/1800Z 16.4N 102.9W   95 KT 110 MPH
 48H  24/0600Z 16.9N 104.8W  105 KT 120 MPH
 72H  25/0600Z 17.9N 108.0W  105 KT 120 MPH
 96H  26/0600Z 18.5N 110.5W   90 KT 105 MPH
120H  27/0600Z 19.0N 113.0W   80 KT  90 MPH
 
$$
FORECASTER BROWN