000
AXPZ20 KNHC 120921
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON SEP 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM EXTREME SOUTHWEST CARIBBEAN WNW 
ACROSS THE COSTA RICA NICARAGUA BORDER AND ENTERS THE EPAC 
WATERS NEAR 10.5N86W TO 10N101W TO 1010 MB LOW PRES AT 17.5N117W 
TO 11N125W TO 1012 MB LOW PRES AT 12N134W TO 09N137W THEN ITCZ 
TO BEYOND 10N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS 
NOTED N OF MONSOON TROUGH AXIS E OF 94W. 

...DISCUSSION...

AT THE SURFACE...A WEAK HIGH PRES RIDGE CONTINUES JUST N OF THE 
NW WATERS PRODUCING MAINLY LIGHT TO MODERATE NE TRADEWINDS. 
BROAD CYCLONIC FLOW AROUND A TROPICAL WAVE CURRENTLY OVER THE 
WESTERN CARIBBEAN HAS INDUCED NELY FLOW OVER THE SOUTHERN GULF 
OF MEXICO. THIS FLOW IS FUNNELING THROUGH THE CHIVELA PASS INTO 
THE GULF OF TEHUANTEPEC...RESULTING IN FRESH 20 KT WINDS. 
GUIDANCE SUGGESTS WINDS WILL INCREASE ACROSS THE GULF OF 
TEHUANTEPEC TO 20 TO 25 KT TODAY.

THE PAIR OF LOW PRESSURE AREAS THAT HAVE BEEN EMBEDDED WITHIN 
THE MONSOON TROUGH MENTIONED ABOVE CONTINUE TO SLOWLY WEAKEN AND 
BOTH ARE EXPECTED TO DISSIPATE WITHIN THE NEXT 48 HOURS. 

NORTHERLY SWELLS...RESULTING IN COMBINED SEAS OF 8 FT...PREVAILS 
OVER THE WATERS N OF 26N BETWEEN 122W AND 135W. THESE SWELLS ARE 
EXPECTED TO SUBSIDE BELOW 8 FT TONIGHT. CROSS EQUATORIAL SW 
SWELL...WITH SEAS TO 9 FT...PREVAILS OVER MUCH OF THE AREA S OF 
10N W OF 90W. THIS SWELL EVENT WILL CONTINUE TO SPREAD NORTHWARD 
THROUGH THE FORECAST PERIOD REACHING THE COAST OF MEXICO S OF 
SOUTHERN BAJA CALIFORNIA TODAY.

$$
AL