000
AXPZ20 KNHC 250305
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH FROM 08N78W TO 10N90W TO 15N100W TO LOW PRES 1006 
MB NEAR 20N111W THEN RESUMES AT 13N115W TO 15N128W TO 09N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 12N TO 16N 
BETWEEN 102W AND 110W. SCATTERED MODERATE IS WITHIN 120 NM S OF 
TROUGH BETWEEN 112W AND 127W...AND WITHIN 120 NM S OF TROUGH
BETWEEN 84W AND 90W. 

...DISCUSSION...
ALOFT...NE TO E UPPER LEVEL WINDS DOMINATE THE EPAC E OF 125W TO 
THE S OF AN ANTICYCLONIC CIRCULATION LOCATED OVER NORTHERN BAJA 
CALIFORNIA NEAR 31N115W. SATELLITE DERIVED WINDS WERE 35-45 KT. 
A RIDGE EXTENDS FROM THE ANTICYCLONE TO A COL NEAR 19N131W. 
UPPER DIFFLUENCE SOUTH OF THIS SYSTEM IS HELPING TO INDUCE THE 
CONVECTION PREVIOUSLY MENTIONED IN THE MONSOONAL FLOW. ANOTHER 
ANTICYCLONE IS NEAR 20N140W. THE NW CORNER OF THE FORECAST AREA 
IS UNDER THE INFLUENCE OF AN UPPER-LEVEL TROUGH ANCHORED TO A 
RATHER VIGOROUS CYCLONIC CIRCULATION NEAR 31N133W. 

AT THE SURFACE...WEAK RIDGE DOMINATES THE NW CORNER OF THE 
FORECAST REGION. THE REMNANT LOW OF GREG HAS DEGENERATED INTO A 
SURFACE TROUGH EXTENDING FROM 16N133W TO 21N131W. INFRARED 
SATELLITE IMAGERY SHOWS A WEAK SWIRL OF LOW CLOUDS ASSOCIATED 
WITH THIS FEATURE. EXPECT THE TROUGH TO DISSIPATE COMPLETELY 
WITHIN 24 HOURS. 

SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED IN ASSOCIATION 
WITH A WEAK LOW PRESSURE AREA CENTERED NEAR 20N111W. THE LOW HAS
HAS CROSSED OVER COOLER WATERS WITH ALL DEEP CONVECTION 
DISSIPATED. AN EARLIER 1642 UTC ASCAT PASS INDICATED AN AREA OF 
NW WINDS OF 20 KT WITHIN 150 NM IN THE SW SEMICIRCLE OF LOW 
CENTER.

FRESH SW WINDS ARE SEEN S OF THE MONSOON TROUGH COVERING THE 
AREA FROM 08N TO 12N BETWEEN 104W AND 115W. NWP WAVE MODEL 
GUIDANCE CONTINUES TO SHOW SEAS BUILDING 9-11 FT FROM SUSTAINED 
SW WINDS ACROSS THE REGION S OF THE MONSOON TROUGH. GLOBAL MODEL 
GUIDANCE SUGGESTS THE MONSOON TROUGH WILL REMAIN MODERATELY 
ACTIVE THE NEXT COUPLE OF DAYS. 

PRES GRADIENT BETWEEN THE ABOVE MENTIONED RIDGE AND LOW PRES 
OVER NW MEXICO IS RESULTING IN NW WINDS OF UP TO 20 KT N OF 27N 
E TO 120W TO THE W COAST OF BAJA CALIFORNIA. LITTLE CHANGE TO 
THIS PATTERN IS EXPECTED OVER THE NEXT 24 HOURS. WINDS ARE 
EXPECTED TO DROP BELOW 20 KT BEYOND 24 HOURS. 

SE SWELLS WILL PROPAGATE ACROSS THE S WATERS MAINLY S OF 10N AND 
W OF 100W THROUGH THU BUILDING SEAS TO 8-9 FT.

$$
COBB