000
AXPZ20 KNHC 202135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU AUG 20 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 
2130 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 90W N OF 04N INTO CENTRAL AMERICA 
MOVING W AT 15 KT. SCATTERED MODERATE CONVECTION IS FROM 09N-12N 
BETWEEN 87W-93W.
 
A TROPICAL WAVE IS ALONG 116W FROM 07N-16N MOVING W AT 10 KT. 
BROAD CYCLONIC TURNING IS NOTED NEAR 11N116W. SCATTERED MODERATE 
TO ISOLATED STRONG CONVECTION IS W OF THE WAVE AXIS FROM 09N-12N 
BETWEEN 116W-120W. 

A TROPICAL WAVE IS ALONG 131W FROM 08N-17N MOVING W AT 10 KT. A  
1007 MB LOW IS EMBEDDED ON THE WAVE AXIS AT 13N131W. CLUSTERS OF 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 
08N-15N BETWEEN 128W-135W.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 09N84W 
11N90W 09N100W 12N120W 13N131W 10N140W. WIDELY SCATTERED 
MODERATE CONVECTION IS S OF PANAMA FROM 05N-10N BETWEEN 77W-82W. 
SCATTERED MODERATE CONVECTION IS FROM 09N-12N BETWEEN 
93W-100W...AND FROM 08N-10N BETWEEN 100W-107W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 09N-13N BETWEEN 
120W-124W...AND FROM 09N-11N BETWEEN 137W-140W. 

WIDELY SCATTERED MODERATE CONVECTION IS NOTED SE OF ACAPULCO 
FROM 12N-16N BETWEEN 96W-100W.

...DISCUSSION...

A 1026 MB HIGH IS NW OF THE AREA NEAR 36N148W. A RIDGE AXIS 
EXTENDS SE TO 33N140W TO THE S COAST OF BAJA CALIFORNIA AT 
23N117W. 10-15 KT NE WINDS ARE NOTED IN VICINITY OF THE RIDGE. 
IN THE TROPICS...05-10 KT TRADES ARE PREDOMINATELY E OF 120W 
HOWEVER...15 KT NE WINDS ARE DOWNSTREAM OF THE GULF OF PAPAGAYO 
AND WILL PREVAIL FOR THE NEXT FEW DAYS. TRADES ARE ALSO 10-15 KT 
W OF 120W. SCATTERED SHOWERS ARE ALONG THE COAST OF MEXICO FROM 
THE GULF OF TEHUANTEPEC TO ACAPULCO TO 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 SOUTHERLY SWELLS AT A PERIOD OF 18 SECONDS ARE 
EXPECTED TO REACH THE COAST OF CENTRAL AMERICA S OF THE BAJA 
PENINSULA TONIGHT AND REACH SOUTHERN CALIFORNIA FRI NIGHT.     

IN THE UPPER LEVELS...
AN UPPER LEVEL LOW IS CENTERED AT 19N138W. A SECOND UPPER LEVEL 
LOW IS CENTERED AT 32N123W. AN UPPER LEVEL HIGH IS IN BETWEEN 
CENTERED NEAR 22N128W. FURTHER E...ZONAL FLOW IS FROM 80W TO 
110W. 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