000
AXPZ20 KNHC 242142
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED AUG 24 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 10N86W TO 14N100W TO LOW PRES 1006 MB NEAR 
19N111W THEN RESUMES AT 14N112W TO 15N128W TO 09N140W. SCATTERED 
MODERATE CONVECTION IS WITHIN 150 NM SOUTH OF TROUGH BETWEEN 85W 
AND 90W. SIMILAR CONVECTION IS NOTED IN THE MONSOONAL FLOW FROM 
14N TO 18N BETWEEN 102W AND 109W. 

...DISCUSSION...
ALOFT...NE TO E UPPER LEVEL WINDS DOMINATE THE EPAC E OF 120W TO 
THE S OF AN ANTICYCLONIC CIRCULATION LOCATED OVER NORTHERN BAJA 
CALIFORNIA NEAR 31N115W. A RIDGE EXTENDS FROM THIS ANTICYCLONE 
TO NEAR 18N130W. 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 WHICH IS PRODUCING SW TO W WINDS. 

WEAK RIDGE DOMINATES THE NW CORNER OF THE FORECAST REGION. 1014 
MB REMNANT LOW OF GREG IS NEAR 19N131W. VISIBLE SATELLITE 
IMAGERY SHOWS A WEAK SWIRL OF LOW CLOUDS ASSOCIATED WITH THIS 
SYSTEM...AND LATEST ASCAT PASS INDICATES THAT WINDS HAVE 
DIMINISHED BELOW 20 KT NW OF THE CENTER IN THE WEAKENING PRES 
GRADIENT. EXPECT THE LOW TO DISSIPATE COMPLETELY WITHIN 6-12 
HOURS WITH ONLY A WEAK TROUGHING REMAINING. 

SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED IN ASSOCIATION 
WITH A WEAK LOW PRESSURE AREA CENTERED NEAR 20N111W. THE LOW IS 
EXPECTED TO REACH COOLER WATERS WITHIN 24 HOURS AND SIGNIFICANT 
DEVELOPMENT OF THIS DISTURBANCE IS UNLIKELY. NW WINDS OF 20 KT 
AND SEAS TO 8 FT ARE NOTED WITHIN 150 NM SW SEMICIRCLE OF LOW 
CENTER.

A 1013 MB LOW PRES EMBEDDED IN THE MONSOON TROUGH IS NOTED NEAR 
11N137W. THE MOST RECENT WINDSAT PASS SHOWS NLY WINDS OF 20 TO 
25 KT WITHIN 180 NM NW 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. THE 1644 ASCAT PASS CONFIRMED THESE 
WIND SPEEDS. MARINE GUIDANCE CONTINUES TO SHOW BUILDING SEAS TO 
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. SEVERAL SHIP 
REPORTS AND THE MOST RECENT WINDSAT PASS PROVIDED OBSERVATIONS 
OF THESE WINDS. LITTLE CHANGE TO THIS PATTERN IS EXPECTED OVER 
THE NEXT 24 HOURS AS HIGH PRES CURRENTLY LOCATED NEAR 33N135W 
DRIFTS TO THE SW. 

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

$$
GR