000
AXPZ20 KNHC 211559
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI AUG 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 
1500 UTC.

...SPECIAL FEATURES...
A 1007 MB LOW IS CENTERED NEAR 13N132W MOVING W AT 8 KT. THIS 
SYSTEM HAS THE POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING 
THE NEXT DAY OR TWO. SCATTERED MODERATE TO STRONG CONVECTION IS 
S OF THE CENTER FROM 10N-13N BETWEEN 129W-133W. SIMILAR 
CONVECTION IS NW OF THE CENTER FROM 13N-16N BETWEEN 133W-136W. 

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 100W N OF 08N MOVING W 15 KT. SHORTWAVE 
IR SATELLITE IMAGES SHOW A BROAD AND ELONGATED AREA OF LOW TO 
MID-LEVEL CYCLONIC TURNING ASSOCIATED WITH THIS FEATURE. TOTAL 
PRECIPITABLE WATER IMAGES REVEAL A LARGE ZONE OF HIGHLY MOIST 
CONDITIONS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
MOSTLY E OF THE WAVE AXIS FROM 09N-14N BETWEEN 94W-99W.

TROPICAL WAVE IS ALONG 119W FROM 09N TO 17N MOVING W 10 KT. 
BROAD LOW TO MID-LEVEL CYCLONIC TURNING...COVERING 8 TO 10 
DEGREES OF LONGITUDE...IS APPARENT ON SATELLITE IMAGES. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 09N-13N 
BETWEEN 114W-123W. 

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 09N84W 12N100W 13N132W 10N140W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 09N TO 
14N BETWEEN 94W AND 99W...AND FROM 09N TO 13N BETWEEN 114W AND 
123W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 10N TO 13N 
BETWEEN 129W AND 133W...AND FROM 13N TO 16N BETWEEN 133W AND 
136W.

SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS N OF THE 
ITCZ FROM 13N TO 19N BETWEEN 102W AND 107W.

...DISCUSSION...

A 1032 MB HIGH IS NW OF THE AREA NEAR 44N150W. A RIDGE AXIS 
EXTENDS SE TO 36N140W TO THE S COAST OF BAJA CALIFORNIA AT 
22N115W. 10-15 KT NE WINDS ARE NOTED IN VICINITY OF THE RIDGE. 
IN THE TROPICS...05-10 KT TRADES ARE PREDOMINATELY E OF 120W.  
TRADES ARE ALSO 10-15 KT W OF 120W. SCATTERED SHOWERS ARE ALONG 
THE COAST OF MEXICO NEAR MAZATLAN. SSMI TOTAL PRECIPITABLE WATER 
ALSO SHOWS CONSIDERABLE MOISTURE N OF 03N FROM ECUADOR TO BAJA 
CALIFORNIA AT 110W. THE SAME SSMI MOISTURE EXTENDS W ALONG THE 
ITCZ FROM 03N -17N W OF 110W TO BEYOND 140W.       

LONG PERIOD...15-18 SECONDS...S TO SW SWELL IS PROPAGATING 
ACROSS MUCH OF THE AREA AND WILL CONTINUE FOR THE NEXT COUPLE OF 
DAYS. THIS WILL LIKELY CAUSE LARGE BREAKING WAVES ALONG THE 
COASTLINES OF CENTRAL AMERICA AND MEXICO. 

IN THE UPPER LEVELS...
AN UPPER LEVEL HIGH IS CENTERED AT 23N132W. AN UPPER LEVEL LOW 
IS CENTERED OFF THE COAST OF S CALIFORNIA AT 31N122W. AN UPPER 
LEVEL HIGH IS CENTERED OVER MEXICO NEAR 22N104W. FURTHER S IN 
THE TROPICS S OF 15N...ZONAL FLOW IS FROM 80W TO 140W. STRONG 
SUBSIDENCE IS NOTED N OF 17N BETWEEN 110W-140W. CONSIDERABLE 
UPPER LEVEL MOISTURE IS OVER THE REMAINDER OF THE AREA NAMELY 
OVER CENTRAL AMERICA AND THE TROPICS FROM 03N-17N. 

$$
FORMOSA