000
AXPZ20 KNHC 250307
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN SEP 25 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0215 UTC.

...SPECIAL FEATURE...

HILARY CONTINUES AS A CATEGORY FOUR HURRICANE. AT 25/0300 UTC... 
IT IS CENTERED NEAR 17.1N 107.7W MOVING W OR 270 DEG AT 8 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 950 MB. MAXIMUM SUSTAINED 
WINDS ARE 115 KT GUSTS TO 140 KT. SOME FLUCTUATIONS IN INTENSITY 
ARE LIKELY IN THE SHORT TERM...BUT THE OVERALL TREND IS FOR 
HILARY TO SLOWLY WEAKEN. NUMEROUS STRONG CONVECTION IS WITHIN 70 
NM E AND 50 NM W OF CENTER. SCATTERED TO NUMEROUS MODERATE TO 
STRONG CONVECTION ELSEWHERE FROM 15N TO 19N BETWEEN 105W AND 
109W. SWELLS GENERATED BY HILARY ARE STILL AFFECTING PORTIONS OF 
THE COAST OF SOUTHWESTERN MEXICO. THESE SWELLS ARE LIKELY CAUSING
LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC 
FOR MORE DETAILS. 
 
...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 09N90W TO 07N97W THEN 
RESUMES W OF HURRICANE HILARY NEAR 15N110W TO 13N125W TO 11N140W.
SCATTERED MODERATE TO ISOLATED STRONG WITHIN 150 NM S OF TROUGH 
BETWEEN 84W AND 90W...AND WITHIN 90 NM S OF TROUGH BETWEEN 96W 
AND 98W. ISOLATED MODERATE FROM 10N TO 13N BETWEEN 120W AND 130W.

...DISCUSSION... 

A 1020 MB HIGH IS CENTERED NEAR 28N133W WITH A WEAK RIDGE AXIS 
EXTENDING SE TO SOUTHERN BAJA CALIFORNIA NEAR 23N113W. PRESSURE 
GRADIENT BETWEEN THE HIGH PRES AND LOWER PRES OVER NW MEXICO IS 
RESULTING IN FRESH NW WINDS N OF 23N E OF 115W TO THE W COAST OF 
BAJA CALIFORNIA. THIS SYSTEM IS FORECAST TO REMAIN NEARLY 
STATIONARY. A COLD FRONT IS JUST NW OF THE FORECAST AREA 
CROSSING NEAR 31N140W. SW WINDS OF 15 KT ARE NOTED OVER THE FAR 
NW PORTION WITH SEAS TO 8 FT IN NW SWELL AFFECTING THE WATERS N 
OF 29N W OF 135W. LITTLE CHANGE IS EXPECTED IN ABOUT 24 HOURS 
WITH SEAS SUBSIDING BELOW 8 FT IN 36-48 HOURS. 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 110W AND 130W. FRESH MONSOONAL FLOW PREVAILS S OF 
THE TROUGH AXIS PARTICULARLY FROM 10N TO 13N BETWEEN 105W AND 
115W. WEAK HIGH PRESSURE ACROSS THE W COAST OF THE GULF OF 
MEXICO SUPPORTING MODERATE TO 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 ARE MERGING WITH SW SWELL FROM THE SOUTHERN HEMISPHERE 
MAINLY S OF 10N. AS HILARY MOVES FURTHER W...SE SWELL WILL BEGIN 
TO MOVE INTO THE SOUTHERN GULF OF CALIFORNIA SUNDAY AND MONDAY.

$$
GR/DM