000
AXPZ20 KNHC 300330
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI SEP 30 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 
0245 UTC.

...SPECIAL FEATURE...
TROPICAL STORM HILARY AT 21.9N 120.8W AT 0300 UTC MOVING N-NW OR 
335 DEG AT 5 KT WITH CENTRAL PRES OF 1002 MB. MAXIMUM SUSTAINED 
WIND 40 GUSTS TO 50 KT. CONVECTION HAS WEAKENED AND IS WELL 
REMOVED TO THE NE OF THE SYSTEM. HILARY CONTINUES TO WEAKEN 
QUICKLY...AS COOL WATERS AND VERTICAL WIND SHEAR ADVERSELY 
IMPACT STORM ORGANIZATION. THIS ENVIRONMENT IS EXPECTED TO 
FURTHER WEAKEN HILARY TO EXTINCTION BY THE WEEKEND. SWELLS 
GENERATED BY HILARY CONTINUE TO AFFECT W COAST OF BAJA 
CALIFORNIA...SOUTHERN GULF OF CALIFORNIA...AND ADJACENT PORTIONS 
OF SW MEXICO...CAUSING HIGH SURF AND LIFE-THREATENING RIP 
CURRENT CONDITIONS.  SEE LATEST NHC FORECAST/ ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 
 
...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE SW CARIBBEAN NW THROUGH 
CENTRAL AMERICA ENTERING THE E PACIFIC NEAR 10N86W TO 12N103W TO 
09N108W TO 12N120W TO 10N135W...THEN ITCZ FROM 10N135W TO BEYOND 
10N140W. SCATTERED MODERATE WITHIN 240 NM S OF TROUGH BETWEEN 
115W AND 122W. 

...DISCUSSION...
A COLD FRONT HAS MOVED INTO THE FAR NW CORNER OF BASIN FROM 
30N137W TO 28N140W. WINDS BEHIND THE FRONT WILL REMAIN BELOW 20 
KT...BUT WILL USHER IN SEAS TO 8 FT IN NW SWELL. THE FRONT WILL 
REACH FROM 30N127W TO 24N140W BY SAT NIGHT...WITH 8 FT SEAS 
SPREADING SE WITH THE FRONT.

STATIONARY LOW PRES CENTER 1010 MB NEAR 11N133W IS PRODUCING 
FRESH 20 KT WINDS WITHIN 60 NM OF ITS CENTER. THE COVERAGE OF 
THE FRESH 20 KT WINDS WILL DECREASE THROUGH 24 HOURS...THEN 
WINDS WILL DIMINISHES TO MODERATE BREEZE.  
 
LONG PERIOD SWELL TRAINS DUE TO SEVERAL DIFFERENT SOURCES 
CONTINUE TO MAKE CONFUSED SEAS ACROSS A LARGE PORTION OF E PAC. 
THESE SWELLS WILL GRADUALLY SUBSIDE THROUGH THE NEXT 48 HOURS.  

GRADIENT FROM HIGH PRES CENTER 1013 MB OVER THE NW GULF OF 
MEXICO WILL INDUCE STRONG WINDS ACROSS CHIVELAS PASS INTO THE 
GULF OF TEHUANTEPEC BY LATE FRI. CURRENT FORECAST INDICATES N TO 
NE WINDS MAY REACH NEAR GALE FORCE BY SAT NIGHT.   

$$
AL