000
AXPZ20 KNHC 180312
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED AUG 18 2010

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

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

...TROPICAL WAVE...

A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA AND GUATEMALA 
ALONG 89W/90W MOVING W AROUND 10 KT AND EXTENDING S INTO THE 
EPAC TO NEAR 12N. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS WITHIN 130 NM E OF AXIS FROM 13N TO 15.5N. THIS 
ACTIVITY IS AFFECTING PARTS OF EL SALVADOR AND WESTERN 
HONDURAS.  

...ITCZ...

THE ITCZ AXIS IS ALONG 09N84W TO 08N102W THEN RESUMES AT 12N105W 
TO 10N120W TO 12N128W TO 08N140W. SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION IS NOTED FROM 07N TO 10N BETWEEN 87W AND 
94W...AND FROM 06N TO 08N BETWEEN 131W AND 133W. 

...DISCUSSION...

ALOFT...A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED 
OVER NORTHERN LOUISIANA EXTENDS A RIDGE ACROSS MEXICO INTO THE 
EPAC COVERING ROUGHLY THE AREA N OF 15N E OF 125W. ANOTHER UPPER 
LEVEL ANTICYCLONE IS OVER THE NW WATERS NEAR 22N133W WITH RIDGE 
EXTENDING SW TO BEYOND 20N140W AND NORTHEAST TO 29N128W. IN 
BETWEEN...THERE IS A SHORT-WAVE TROUGH ALONG 127W/128W TO A COL 
NEAR 23N128W. MODERATE TO STRONG SUBSIDENCE DOMINATES THE AREA N 
OF 20N W OF TROUGH. OTHERWISE...EASTERLY FLOW PREVAILS IN THE 
DEEP TROPICS S OF 10N. 

AT THE SURFACE...A WEAK SURFACE RIDGE COVERS THE NW WATERS 
PARTICULARLY N OF 18N W OF 120W. PRES GRADIENT IS FORECAST TO 
TIGHTEN BETWEEN THE RIDGE AND LOWER PRES OVER NW MEXICO IN ABOUT 
48 HOURS PRODUCING NW WINDS OF 20 KT FROM 24N TO 27N E OF 115W 
TO THE COAST OF BAJA CALIFORNIA. THE LOW PRES THAT WAS LOCATED 
NEAR 22N112W HAS DISSIPATED. HOWEVER...A SWIRL OF LOW CLOUDS IS 
STILL NOTED ON SATELLITE IMAGERY ASSOCIATED WITH THIS SYSTEM. A 
SURFACE TROUGH LIES ALONG 17N105W TO 14N100W TO 11N95W. 
CONVECTION ASSOCIATED WITH THIS TROUGH HAS DIMINISHED DURING THE 
LAST FEW HOURS. ANOTHER SURFACE TROUGH EXTENDS FROM 18N132W TO A 
WEAK 1011 MB LOW LOCATED NEAR 12N130W. A SWIRL OF LOW CLOUDS IS 
ALSO ASSOCIATED WITH THIS LOW.

CROSS EQUATORIAL SW SWELLS ARE RAISING SEAS UP TO 9 FT OVER S 
CENTRAL WATERS...AND IS FORECAST TO SLOWLY MOVE NORTH OF 10N BY 
LATE WED. THIS SWELL EVENT WILL GRADUALLY MAKE ITS WAY E OF THE 
GALAPAGOS ISLANDS...AND SEAS WILL REACH 8 FT OFF THE COAST OF 
PANAMA NEAR 06N IN ABOUT 24 HOURS. 

$$
GR