000
AXPZ20 KNHC 210901
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED JUL 21 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0815 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 15N96W TO 
12N103W TO 11N117W TO 12N126W TO 09N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE ITCZ AXIS 
BETWEEN 121W AND 123W.


...DISCUSSION...

AN UPPER LEVEL RIDGE ENTERS THE AREA FROM 24N140W TO 30N135W 
WITH VERY DRY AIR IN PLACE W OF 134W. AN UPPER LEVEL LOW IS 
CENTERED NEAR 29N127W AND EXTENDS A WEAK TROUGH TO 19N136W WITH 
MID TO UPPER LEVEL MOISTURE EVIDENT N OF 26N BETWEEN 125W AND 
133W. THIS UPPER TROUGH IS EXPECTED TO REMAIN NEARLY STATIONARY 
DURING THE NEXT 48 HOURS. AN UPPER LEVEL HIGH IS POSITIONED NEAR 
19N117W WITH A RIDGE EXTENDING SW TO NEAR 15N124W. AN UPPER 
LEVEL LOW IS JUST NE OF THIS HIGH NEAR 24N113W. DEEP LAYERED 
MOISTURE IS MOVING N OF THIS UPPER CYCLONE UP THE GULF OF 
CALIFORNIA AND ACROSS THE NORTHERN PORTION OF BAJA CALIFORNIA 
AND W MEXICO. THE UPPER LEVEL FLOW PATTERN S OF 17N E OF 110W IS 
DOMINATED BY E-NE WINDS WITH ABUNDANT MOISTURE ADVECTING FROM 
CENTRAL AMERICA INTO THE E PAC FEEDING SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION WITHIN 90/120 NM ALONG THE COAST OF 
CENTRAL AMERICA AND S MEXICO N OF 10N TO THE GULF OF 
TEHUANTEPEC. 

A 1039 MB HIGH PRES AT THE SURFACE IS CENTERED WELL NW OF THE 
DISCUSSION AREA WITH A RIDGE AXIS EXTENDING THROUGH 32N137W TO 
23N128W WITH VERY DRY AND STABLE AIR. A WEAK TROUGH...THE 
REMNANTS OF T.D. SIX-E...REMAINS FROM 20N128W TO 16N130W WITH NO 
CONVECTION EVIDENT WITH THIS FEATURE. REGENERATION OF THIS 
SYSTEM IS NOT ANTICIPATED.

GALE FORCE WINDS ALONG THE PACIFIC NW COAST OF THE U.S. CONTINUE 
TO GENERATE NORTHERLY SWELL IN THE 8 TO 10 FT RANGE APPROACHING 
THE DISCUSSION AREA N OF 25N BETWEEN 118W AND 132W. THIS SWELL 
WILL CONTINUE...KEEPING SEAS TO 9 FT PRIMARILY IN THE AREA N OF 
26N BETWEEN 120W AND 130W TODAY AND SUBSIDING TO 8 FT THU NIGHT. 

LONG PERIOD CROSS EQUATORIAL SOUTHERLY SWELL OF 8 TO 9 FT LIES 
ACROSS THE S PORTION OF THE BASIN PRIMARILY S OF 11N BETWEEN 95W 
AND 130W. THIS SWELL WILL GRADUALLY DECAY OVER THE NEXT TWO 
DAYS...BUT A NEW SURGE OF SE SWELL IS EXPECTED TO BEING MOVING 
ACROSS THE EQUATOR THU NIGHT. SE TO S WINDS ARE EXPECTED TO 
INCREASE TO 20 KT WED AND THU IN S CENTRAL WATERS. THIS WILL 
ALSO HELP KEEP SEAS ABOVE 8 FT IN MUCH OF THE REGION S OF 10N.

$$
PAW