000
AXPZ20 KNHC 242140
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT SEP 24 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...SPECIAL FEATURE...

HURRICANE HILARY NEAR 16.9N 106.8W AT 2100 UTC MOVING W OR 270 
DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 951 MB. 
MAXIMUM SUSTAINED WINDS ARE 115 KT GUSTS TO 140 KT. SATELLITE 
IMAGERY INDICATES THAT WHILE HILARY HAS MADE AN UNUSUAL TRACK 
OSCILLATION OVER THE PAST 6-12 HOURS...LARGE SCALE MOTION IS TO 
THE WEST. IT HAS ALSO PEAKED IN INTENSITY AND NOW HAS A LARGER 
EYE. HILARY IS EXPECTED TO VERY SLOWLY DECREASE IN INTENSITY THE 
NEXT 2-3 DAYS AS IT MOVES W OVER WARM WATERS IN A MINIMAL UPPER 
WIND SHEAR ENVIRONMENT. NUMEROUS STRONG CONVECTION WITHIN 60 NM 
N AND 70 NM S OF CENTER. SCATTERED TO NUMEROUS MODERATE TO STRONG
CONVECTION ELSEWHERE WITHIN 150 NM N AND 180 NM S OF CENTER.
 
...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 09N90W TO 07N97W THEN 
RESUMES W OF HURRICANE HILARY NEAR 14N113W TO 12N125W TO 11N136W.
ITCZ AXIS W OF 11N136W. SCATTERED MODERATE CONVECTION FROM 04N 
TO 08N E OF 90W TO THE COAST OF COLOMBIA. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION FROM 04N TO 10N BETWEEN 90W AND 100W. 
SCATTERED MODERATE CONVECTION FROM 10N TO 12N BETWEEN 107W AND 
115W...AND WITHIN 60-90 NM EITHER SIDE OF THE MONSOON TROUGH 
BETWEEN 115W AND 132W.

...DISCUSSION... 

A 1020 MB HIGH IS CENTERED NEAR 27N131W WITH A WEAK RIDGE AXIS 
EXTENDING SE TO SOUTHERN BAJA CALIFORNIA NEAR 23N113W. PRESSURE 
GRADIENT FROM THE HIGH AND A WEAK TROUGH OVER THE GULF OF MEXICO 
IS PRODUCING FRESH NW WINDS FROM 23N TO 28N W OF BAJA. A COLD 
FRONT OFF THE WEST COAST OF THE U.S. EXTENDS TO THE NW CORNER OF 
THE DISCUSSION AREA. OVER THE NEXT 24 HOURS THE HIGH IS EXPECTED 
TO REMAIN NEARLY STATIONARY...WHILE THE COLD FRONT WEAKENS AND 
BRUSHES PAST THE NW PORTION BUILDING SEAS TO 8 FT IN NW SWELL... 
AND OCCASIONAL 20 KT WINDS CONTINUING NEAR BAJA CALIFORNIA. LIGHT
TO MODERATE N-NE TRADE WINDS DOMINATE THE REGION N OF THE MONSOON
TROUGH W OF 120W.

SEVERAL WEAK DISTURBANCES EMBEDDED WITHIN THE MONSOON TROUGH ARE 
PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS ALONG THE TROUGH 
AXIS BETWEEN 115W AND 132W. LIGHT TO MODERATE S TO SW MONSOONAL 
FLOW PREVAILS S OF THE TROUGH. WEAK HIGH PRESSURE ACROSS THE W 
COAST OF THE GULF OF MEXICO SUPPORTING FRESH N WINDS IN THE GULF 
OF TEHUANTEPEC ARE EXPECTED TO LAST UNTIL SUN MORNING.

HURRICANE HILARY IS GENERATING LARGE LONG-PERIOD SWELL WITH SEAS 
GREATER THAN 8 FT UP TO 300 NM AWAY FROM THE CENTER...AND GREATER
THAN 12 FT UP TO 120 NM FROM HILARY. MARINE CONDITIONS ELSEWHERE 
REMAIN FAIRLY BENIGN ACROSS THE DISCUSSION AREA. LONG PERIOD NW 
SWELL WILL MERGE WITH SW SWELL FROM THE SOUTHERN HEMISPHERE 
TODAY S OF 10N. AS HILARY MOVES FURTHER W...SE SWELL WILL BEGIN 
TO MOVE INTO THE SOUTHERN GULF OF CALIFORNIA SUNDAY AND MONDAY.

$$
MUNDELL/GR