000
AXPZ20 KNHC 210910
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE AUG 21 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 08N78W TO 06N100W THEN 
CONTINUES FROM LOW PRES NEAR 13N110W TO 10N120W. ITCZ AXIS WAS 
ANALYZED FROM 10N120W TO LOW PRES NEAR 12N129W TO 09N140W. 
SCATTERED MODERATE CONVECTION WAS WITHIN 180 NM N OF THE AXIS 
BETWEEN 84W AND 87W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 
NM S SEMICIRCLE OF THE LOW PRES SYSTEM NEAR 13N110W.

...DISCUSSION...

THE ANTICYCLONE ALOFT OVER FAR NW MEXICO NEAR 30N111W EXTENDS 
RIDGE AXES SOUTHWESTWARD TO 06N140W AND SOUTHEASTWARD ALONG THE 
COAST OF MAINLAND MEXICO TO THE GULF OF TEHUANTEPEC. AN UPPER 
TROUGH FROM 32N130W TO 20N137W IS IMPINGING UPON THE ANTICYCLONE 
FROM THE WEST. THIS TROUGH IS EXPECTED TO PINCH OFF AN UPPER LOW 
THAT SHOULD TRACK INTO THE SW UNITED STATES BY THU...ALLOWING 
THE WESTERN RIDGE TO LIFT NORTHWARD OVER THE NEXT FEW DAYS 
BEHIND THE CUT OFF LOW. DIFFLUENT CONDITIONS ASSOCIATED WITH THE 
EASTERN RIDGE AXIS ALOFT ARE ENHANCING THE CONVECTION ALONG THE 
COAST OF MAINLAND MEXICO. SCATTERED MODERATE CONVECTION WAS 
WITHIN 75 NM OF THE MAINLAND MEXICAN COAST BETWEEN 95W AND 99W 
AND FROM 21N TO 25N AS WELL AS INLAND PRIMARILY W OF THE SIERRA 
MADRE OCCIDENTAL. 

THE SUBTROPICAL HIGH HAS BEEN DISPLACED TO THE W BY THE MEAN 
TROUGHING OVER THE FAR EASTERN NORTH PACIFIC. THE 1026 MB HIGH 
CENTER LIES N-NW OF THE HAWAIIAN ISLANDS NEAR 36N165W. THE 
COMPROMISED SUBTROPICAL RIDGE HAS YIELDED TRADE WINDS ONLY AS 
STRONG AS A MODERATE BREEZE OVER THE FORECAST AREA. THE 1013 MB 
REMNANT LOW OF HECTOR WAS ANALYZED ON THE EASTERN EDGE OF THE 
RIDGE NEAR 23N115W. THIS SYSTEM HAS MOVED LITTLE OVER THE LAST 
FEW DAYS AND REFUSES TO OPEN UP INTO A TROUGH. ANOTHER AREA OF 
LOW PRES LIES NEAR THE MOUTH OF THE GULF OF CALIFORNIA NEAR 
20N108W. THE 0404 UTC ASCAT PASS SHOWS A CLOSED CIRCULATION 
AROUND THE CENTER BUT WINDS REMAIN A MODERATE BREEZE OR LESS. 

CROSS-EQUATORIAL SE TO S SWELL TO 8 FT WILL LIE OVER THE 
FORECAST AREA S OF 04N W OF 110W DURING THE NEXT FEW DAYS.   

$$
SCHAUER