000
AXPZ20 KNHC 280307
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JUL 28 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 
0300 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N84W TO 10N90W TO 08N98W TO 
13N108W 13N115W TO 07N124W...THENCE ITCZ AXIS TO 07N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 210 NM S OF 
AXIS FROM 88W TO 93W.

...DISCUSSION...
BROAD UPPER LEVEL ANTICYCLONIC GYRE AT 24N139W RETREATS W AS 
SHARP TROUGH DIGS SW FROM 32N127W TO 12N137W.  VERY DRY 
SUBSIDING AIR MASS N AND W OF TROUGH AXIS.  NARROW RIDGE EXTENDS 
E-W ACROSS 14N-16N E OF 130W BRINGING 20-25 KT NE WIND SHEAR 
CONDITIONS ALOFT TO MOST OF MONSOON TROUGH AXIS.  WITH THESE 
UNFAVORABLE ENVIRONMENT LITTLE OR NO CYCLONIC DEVELOPMENT IS 
EXPECTED...ALBEIT GFS MODEL DOES LOOK POSITIVE ABOUT PRESENT 
WEAK LOW PRES 1007 MB AT 10N88W BY SAT AND BEYOND...WELL OUTSIDE 
PRESENT FORECAST PERIOD.  ELSEWHERE ABUNDANT MOISTURE ALONG 
MONSOON TROUGH E OF 95W REMAINS UNTAPPED UNDER ADVERSE 
ENVIRONMENT ALOFT.  

AT THE LOWER LEVELS...
BROAD RIDGE CENTERED AT 1033 MB HIGH PRES 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 10N88W STRENGTHENS THU AND FRI 
FORCING FRESH SW WINDS FROM 04N TO 07N E OF 90W.
 
$$
WALLY BARNES