000
AXPZ20 KNHC 252128
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU AUG 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH FROM 11N86W TO 16N95W THEN INLAND OVER SW MEXICO 
TO 1002 MB LOW PRES NEAR 18N112W TO 11N120W TO 13N133W TO 
10N140W. SCATTERED MODERATE CONVECTION IS FROM 10N TO 17N 
BETWEEN 100W AND 110W...AND WITHIN 60 NM SE OF LINE FROM 13N110W 
TO 10N109W. 

...DISCUSSION...
ALOFT...NE TO E UPPER-LEVEL WINDS CONTINUE TO DOMINATE MOST OF 
FORECAST WATERS S OF 20N AND S OF AN ANTICYCLONIC CIRCULATION 
LOCATED OVER SW CONUS WHICH EXTENDS A RIDGE TO THE SW TO A COL 
NEAR 20N132W. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH THIS 
RIDGE IS HELPING TO INDUCE SOME CONVECTION S OF THE MONSOON 
TROUGH PARTICULARLY FROM 10N TO 17N BETWEEN 100W AND 110W. 
ANOTHER ANTICYCLONE IS NEAR 18N140W. AN UPPER-LEVEL TROUGH 
ENTERS THE FORECAST REGION NEAR 30N132W THEN CONTINUES SW TO 
BEYOND 25N140W. THIS TROUGH IS ANCHORED TO A RATHER VIGOROUS 
CYCLONIC CIRCULATION LOCATED N OF AREA NEAR 35N130W.

AT THE SURFACE...WEAK RIDGE REMAINS IN CONTROL OF THE WEATHER 
PATTERN ACROSS THE NW CORNER OF THE AREA. A LOW PRES TROUGH... 
WHAT IS LEFT OF REMNANT LOW GREG...EXTENDS FROM 20N132W TO 
14N135W. LIGHT TO MODERATE WINDS ARE EITHER SIDE OF THE TROUGH 
AXIS PER THE MOST RECENT WINDSAT PASS. 

FRESH TO STRONG S TO SW WINDS S OF THE MONSOON TROUGH DOMINATE A 
LARGE AREA FROM 07N TO 15N BETWEEN 105W AND 115W AND FROM 07N TO 
12N BETWEEN 115W AND 122W. SIMILAR WINDS CAN ALSO BE FOUND FROM 
05N TO 10N BETWEEN 87W AND 100W. SCATTEROMETER DATA PROVIDED 
OBSERVATIONS OF THESE WIND SPEEDS. THE MONSOON TROUGH WILL 
REMAIN MODERATELY ACTIVE OVER THE NEXT COUPLE OF DAYS WITH A 
PAIR OF LOWS EXPECTED TO SLOWLY DEVELOP NEAR 18N118W AND 
15N102W. MARINE GUIDANCE CONTINUES TO BUILD SEAS TO 12 OR 13 FT 
BY SAT IN ASSOCIATION WITH THE FRESH TO STRONG MONSOONAL FLOW.  

WINDS W OF BAJA CALIFORNIA HAVE DIMINISHED TO BELOW 20 KT. 
HOWEVER...A SWATH OF NW TO N WINDS OF 15 TO 20 KT IS NOTED PER 
THE 1800 ASCAT PASS BETWEEN THE AFOREMENTIONED RIDGE AND THE LOW 
PRES SYSTEM LOCATED NEAR 18N112W. VISIBLE SATELLITE IMAGERY 
REVEALS A SWIRL OF LOW CLOUDS ASSOCIATED WITH THIS LOW WITH 
SCATTERED MODERATE CONVECTION JUST TO THE S OF THE CENTER. 

$$
GR