000
AXPZ20 KNHC 212127
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI AUG 21 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES...
A 1007 MB LOW IS CENTERED NEAR 14N134W MOVING W AT 8 KT. SHOWERS 
AND THUNDERSTORMS ASSOCIATED WITH THIS LOW CONTINUE TO BECOME 
BETTER ORGANIZED AND HAVE THE POTENTIAL TO BECOME A TROPICAL 
DEPRESSION TODAY OR TONIGHT. SCATTERED MODERATE TO STRONG 
CONVECTION IS W OF THE CENTER FROM 13N-16N BETWEEN 133W-136W. 

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 100W N OF 08N MOVING W 15 KT. SATELLITE 
IMAGERY SHOWS A BROAD AND ELONGATED AREA OF LOW TO MID-LEVEL 
CYCLONIC TURNING. TOTAL PRECIPITABLE WATER IMAGES REVEAL A LARGE 
ZONE OF HIGHLY MOIST CONDITIONS. SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION IS MOSTLY ALONG THE ITCZ FROM 09N-12N BETWEEN 
100W-102W.

TROPICAL WAVE IS ALONG 119W FROM 09N TO 17N MOVING W 5-10 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 MOSTLY ALONG 
THE ITCZ FROM 09N-11N BETWEEN 117W-120W.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 09N84W 12N100W 13N120W 11N125W 
14N134W 11N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 09N TO 14N BETWEEN 91W AND 97W...FROM 09N TO 
12N BETWEEN 100W AND 107W...FROM 08N TO 11N BETWEEN 117W AND 
123W...AND FROM 09N TO 12N BETWEEN 130W AND 133W.

SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS N OF THE 
ITCZ FROM 14N TO 18N BETWEEN 103W AND 107W.

...DISCUSSION...

A 1032 MB HIGH IS NW OF THE AREA NEAR 42N148W. 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 S 
OF 32N. 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