000
AXPZ20 KNHC 272206
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JUL 27 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 EXTENDS FROM 10N85W TO 09N94W TO 07N101W TO 
13N115W TO 08N123W...THENCE ITCZ AXIS TO 07N129W TO BEYOND 
07N140W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 
240 NM OF AXIS FROM 87W TO 91W.

...DISCUSSION...
BROAD UPPER LEVEL ANTICYCLONIC GYRE AT 24N138W RETREATS W AS 
SHARP TROUGH DIGS SW FROM 32N127W TO 16N133W.  VERY DRY 
SUBSIDING AIR MASS N AND W OF TROUGH AXIS.  NARROW RIDGE EXTENDS 
E-W ACROSS 15N-16N E OF 120W BRINGING WIND SHEAR CONDITIONS 
ALOFT TO MOST OF MONSOON TROGH AXIS.  WITH THESE UNFAVORABLE 
ENVIRONMENT LITTLE CYCLONIC DEVELOPMENT IS EXPECTED...ALBEIT GFS 
MODEL DOES LOOK POSITIVE ABOUT PRESENT WEAK LOW PRES 1008 MB AT 
10N87W BY SAT...WELL OUTSIDE PRESENT FORECAST PERIOD.  ELSEWHERE 
ABUNDANT MOISTURE ALONG MONSOON TROUGH E OF 98W REMAINS UNTAPPED 
UNDER ADVERSE ENVIRONMENT ALOFT.  

AT THE LOWER LEVELS...
BROAD RIDGE WELL NW OF REGION CONTINUES PRESSING AGAINST NORTH 
CALIFORNIA COAST WITH GALE FORCE WINDS...ALTHOUGH NOT AFFECTING 
E PAC...DEVELOPING N 8-10 FT SWELLS WHICH SPREAD S INTO BASIN 
LATE FRI.  ON THE OTHER HAND...MODERATE NE TRADES REMAIN ACROSS 
REGION N OF MONSOON TROUGH/ITCZ AXIS.  

CROSS EQUATORIAL SW SWELLS...RESULTING IN SEAS 8 TO 10 FT...ARE 
PROPAGATING NE OVER WATERS S OF 10N FROM 80W TO 118W.  
AFOREMENTIONED LOW PRES AT 10N87W STRENGTHENS THU FORCING FRESH 
SW WINDS FROM 04N TO 07N E OF 90W.  WINDS DIMINISH ON FRI.
 
$$
WALLY BARNES