000
AXPZ20 KNHC 150255
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUN 15 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 10N85W TO 09N93W TO 11N99W TO 
10N105W TO 11N110W TO 08N125W THEN CONTINUES AS THE ITCZ TO 
04N140W. NUMEROUS MODERATE SCATTERED STRONG CONVECTION FROM 05N 
TO 10N BETWEEN 80W AND 90W.

...DISCUSSION...

E OF 110W...A LARGE AREA OF CONVECTION IS ACTIVE ALONG THE 
EASTERN EXTENT OF THE MONSOON TROUGH E OF 90W...MAINLY ALONG THE 
COAST OF COSTA RICA. 20 KT NE TRADES OVER THE SW CARIBBEAN WERE 
NOTED ON AN EARLIER ASCAT PASS AHEAD OF AN APPROACHING TROPICAL 
WAVE CURRENTLY ALONG 75W. THE FRESH NE FLOW IS CONVERGING WITH 
MODERATE SW CROSS-EQUATORIAL FLOW S OF THE MONSOON TROUGH TO 
IGNITE THE LARGE CLUSTERS OF CONVECTION. A SURFACE LOW IS NOTED 
ON SATELLITE IMAGERY OFF THE NW COAST OF COSTA RICA NEAR 09N86W. 
LAND-BASED OBSERVATION IN NW COSTA RICA SHOW THE LOW TO BE 
AROUND 1004 MB...AND IT IS EXPECTED TO MOVE LITTLE THROUGH THE 
NEXT 24 HOURS. CONVECTION WILL LIKELY PERSIST OVERNIGHT OFF THE 
COASTS OF PANAMA AND COSTA RICA WITH THE AID OF OVERNIGHT 
DRAINAGE FLOW. INTERACTION OF THE MONSOON TROUGH AND THE 
APPROACHING WAVE WILL MAINTAIN THE LOW OVER THE NEXT TWO TO 
THREE DAYS AS IT SHIFTS WEST. GLOBAL MODELS INDICATE A LOW 
FORMING IN THIS AREA...AND SLOWLY DEEPENING THROUGH THU. THE GFS 
REMAINS THE MOST AGGRESSIVE...WITH THE OTHER MAJOR MODELS 
SHOWING MOSTLY ENHANCED SW FLOW LATER IN THE WEEK BETWEEN 90W 
AND 110W S OF 12N. MEANWHILE LONG PERIOD SW SWELL WITH HEIGHTS 
OF 8 TO 9 FT WILL COVER THE AREA S OF 10N E OF 105W.  

W OF 110W...1032 MB HIGH PRES IS CENTERED NEAR 37N144W. A 19Z 
ASCAT PASS ALONG WITH SHIP REPORTS ARE SHOWING N TO NE WINDS 
AROUND 20 KT FROM N OF 20N W OF 130W. THE SHIP OBSERVATIONS ALSO 
CONFIRM WAVEWATCH MODEL INITIALIZATION SHOWING N SWELL WITH 
HEIGHTS OF 8 TO 12 FT APPROACHING THE AREA. FURTHER E...SHIP 
REPORTS ARE SHOWING THAT WINDS ARE DIMINISHING ALONG THE COAST 
OF BAJA CALIFORNIA. FURTHER SOUTH...AN AREA OF WEAK AND 
DIMINISHING SHOWERS AND THUNDERSTORMS ARE NOTED FROM 08N TO 12N 
BETWEEN 110W AND 115W. THIS CONVECTION WAS DUE IN PART TO UPPER 
DIVERGENCE ON THE SE SIDE OF A BROAD UPPER LOW CENTERED NEAR 
23N127W...WITH A TROUGH EXTENDING TO 09N130W. 

$$
CHRISTENSEN