000
AXPZ20 KNHC 042114
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN SEP 04 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 
2100 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 10N86W TO 15N95W TO 16N110W TO 
14N125W TO 13N140W. THE INTERTROPICAL CONVERGENCE ZONE AXIS IS W 
OF AREA. SCATTERED MODERATE OVER THE GULF OF TEHUANTEPEC...NEAR 
15N110W AND NEAR 13N123W. 

...DISCUSSION...
AN UPPER LEVEL TROUGH PREVAILS OVER THE NW PART OF THE AREA. 
ASSOCIATED WITH THE UPPER TROUGH IS A SURFACE TROUGH EXTENDING 
FROM 30N132W TO 26N140W. THIS SURFACE TROUGH HAS REPLACED 
SURFACE RIDGING OVER THE NW PART OF THE AREA WHICH HAS RESULTED 
IN A WEAKER PRESSURE GRADIENT OVER THE WESTERN PART OF THE 
AREA...AND WINDS LESS THAN 20 KT. SURFACE RIDGE IS NOT EXPECTED 
TO BUILD BACK IN ACROSS THE NW PART OF THE AREA UNTIL TUE. THIS 
WILL KEEP THE PRESSURE GRADIENT RELATIVELY WEAK OVER THE WEST 
PART OF THE AREA...AND TRADE WINDS LESS THAN 20 KT THROUGH THE 
FORECAST PERIOD. 

LIMITED AREA OF FRESH 20 KT SW MONSOONAL FLOW IS FOUND FROM 08N 
TO 11N BETWEEN 100W AND 115W. THESE LOCALLY STRONGER MONSOONAL 
WINDS ARE INDUCING SPEED CONVERGENCE...AND CORRESPONDS WITH THE 
AREAS WHERE THERE IS ACTIVE CONVECTION. ASIDE FROM THIS...CROSS 
EQUATORIAL SW SWELL GENERALLY PREVAILS S OF 15N E OF 125W. 

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AL