000
AXPZ20 KNHC 211636
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE JUL 21 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 84W N OF 04N MOVING W AT AN AVERAGE SPEED OF 
17 KT OVER THE PAST 24 HOURS. THE WAVE IS SITUATED UNDER A LARGE 
AREA OF UPPER LEVEL DIFFLUENCE ENHANCING DEEP CONVECTION AHEAD 
OF THE AXIS. THE FAVORABLE UPPER AIR PATTERN CONDITIONS ARE 
EXPECTED TO CONTINUE FOR THE NEXT 24-48 HRS. SIGNIFICANT UPPER 
LEVEL TROUGH JUST N OF AREA IN GULF OF MEXICO IS DROPPING SWWD  
AHEAD OF THE WAVE AND SHOULD LIMIT ANY FURTHER DEVELOPMENT OVER 
THE NEXT SEVERAL DAYS. 

TROPICAL WAVE ALONG 120W FROM 05N TO 14N MOVING W AT AN AVERAGE 
SPEED OF 15 KT. AS IN THE CASE OF THE WAVE NOTED ABOVE...THIS 
WAVE IS SITUATED UNDER AN AREA OF DIFFLUENT FLOW ALOFT THAT IS 
ALSO ENHANCING DEEP CONVECTION AHEAD OF THE AXIS. MOST RECENT 
SATELLITE IMAGERY INDICATED MID LEVEL TURNING ALONG THE WAVE 
AXIS NEAR 09-10N. 
 
...ITCZ...
AXIS ALONG 08N83W TO 09N110W TO 07N140W. SCATTERED MODERATE TO 
STRONG WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 118W AND 
135W...AND WITHIN 180 NM S OF THE AXIS BETWEEN 86W AND 90W. 
SCATTERED MODERATE WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 90W 
AND 106W. 

...DISCUSSION...
COMPLEX MID TO UPPER LEVEL TROUGH COVERS THE N PORTION OF THE 
AREA BETWEEN 115W AND 140W. EMBEDDED CYCLONIC CIRCULATIONS ARE 
LOCATED NEAR 19N128W AND 26N123W. THIS TROUGH IS SITUATED 
BETWEEN SEVERAL ANTICYCLONES NEAR 15N145W...NEAR 13N115W AND 
TO THE NE OF THE AREA NEAR THE ARIZONA/MEXICO BORDER. 
ANTICYCLONE NEAR 13N115W IS CONTRIBUTING TO DIFFLUENT PATTERN 
OVER THE WAVE ALONG 120W AND IS ALSO ENHANCING CONVECTION 
ELSEWHERE WITHIN 180 NM OF THE ITCZ BETWEEN 118W AND 135W. 
UPPER LEVEL TROUGH CUTS BETWEEN THIS ANTICYCLONE AND ANOTHER 
OVER SWRN CARIBBEAN SPLITTING FLOW JUST AHEAD OF TROPICAL WAVE 
ALONG 84W ENHANCING DEEP CONVECTION.

NE TO E FRESH GAP WINDS IN GULF OF PAPAGAYO AND DOWNSTREAM WILL 
PULSE TO 20 KT OVER THE NEXT 48 HOURS. LONG PERIOD SW SWELLS 
OF 18-20 SECONDS AND 8-12 FT ARE CROSSING THE EQUATOR AND ARE 
FORECAST TO MOVE THROUGH THE TROPICAL E PACIFIC WED AND POSSIBLY 
IMPACT THE COAST OF MEXICO AND BAJA CALIFORNIA ON THU. THE 
POTENTIAL EXISTS FOR DANGEROUS BREAKING SURF ALONG THE COAST THU 
INTO THE WEEKEND.   

$$
COBB