000
AXPZ20 KNHC 062133
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE SEP 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE W COAST OF COSTA RICA NEAR 
10N86W TO 13N90W TO LOW PRES AT 18N109W TO LOW PRES AT 11N124W 
TO 09N140W. SCATTERED TO LOCALLY NUMEROUS MODERATE AND ISOLATED 
STRONG CONVECTION IS NOTED N OF 10N TO THE COASTLINE BETWEEN 89W 
AND 107W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG 
CONVECTION IS NOTED FROM 07N TO 10N BETWEEN 100W AND 116W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED FROM 
09.5N TO 13N BETWEEN 115W AND 127W. SCATTERED MODERATE 
CONVECTION IS NOTED FROM 07N TO 10N BETWEEN 129W AND 134W. 

...DISCUSSION...

A BROAD UPPER TROUGH OVER THE FAR N WATERS CONTINUES TO WEAKEN 
AND LIFT OUT TO THE NE. A LARGE UPPER ANTICYCLONE IS OVER 
NORTHERN MEXICO NEAR 28N105W WITH A RIDGE AXIS EXTENDING TO A 
SMALLER UPPER ANTICYCLONE TO THE SW NEAR 24N125W CONTINUING TO 
22N140W. DRY AND STABLE AIR UNDER MODERATE TO STRONG SUBSIDENCE 
IS NOTED ON WATER VAPOR SATELLITE IMAGERY N OF 15N W OF 120W. A 
WEAK INVERTED UPPER TROUGH IS WEDGED BETWEEN THE ANTICYCLONES 
EXTENDING FROM 20N115W TO 26N121W. NE TO E FLOW ALOFT PERSISTS S 
OF THE UPPER RIDGING ACROSS THE MAJORITY OF THE REMAINDER OF THE 
DISCUSSION AREA. UPPER LEVEL DIFFLUENCE S OF THE RIDGE AXIS IS 
HELPING TO SUPPORT CONVECTION NEAR THE MONSOON TROUGH AS 
DESCRIBED IN THE SECTION ABOVE.

AT THE SURFACE...A BROAD RIDGE OF HIGH PRES COVERS THE AREA N OF 
16N W OF 115W. WITH A WEAK PRES PATTERN IN PLACE...TRADES REMAIN 
LESS THAN 20 KT ACROSS THE NE PACIFIC WATERS. AN AREA OF 20 KT S 
TO SW WINDS EXISTS FROM 05N TO 10N BETWEEN 120W AND 131W AND 
ALSO FROM 02N TO 09N BETWEEN 107W AND 102W ALONG WITH SEAS TO 9 
FT IN A BROAD MIX OF SWELL. THESE SOUTHERLY WINDS ARE FORECAST 
TO SHIFT AND ENCOMPASS THE AREA FROM 06N TO 12N BETWEEN 100W AND 
118W...ALONG WITH SE TO S 20 TO 25 KT WINDS S OF 10N BETWEEN 
118W AND 134W WITH SEAS BUILDING TO 10 FT IN 24 HOURS...WITH S 
TO SW 20 KT WINDS FROM 06N TO 12N BETWEEN 107W AND 117W IN 48 
HOURS.

1008 MB LOW PRES IS NEAR 18N109W. AN AREA OF E TO SE 20 TO 25 KT 
WINDS EXISTS FROM 15N TO 16.5N BETWEEN 94W AND 101W WITH 8 FT 
SEAS IN S SWELL AND E WIND WAVES WHERE THE PRES GRADIENT IS 
TIGHT BETWEEN THE MONSOON TROUGH AND THE COAST OF MEXICO. BY 24 
HOURS 20 TO 25 KT WINDS WILL BECOME CONFINED TO THE AREA N OF 
15N BETWEEN 94.5W AND 98W WHILE SHIFTING TO THE N TO NE WHERE 
THEY WILL LINGER THROUGH 48 HOURS. 1009 MB LOW PRES IS NEAR 
11N124W. THIS LOW WILL REMAIN NEARLY STATIONARY THROUGH THE NEXT 
48 HOURS WITH NO SIGNIFICANT DEVELOPMENT EXPECTED.

OTHERWISE...LONG PERIOD CROSS EQUATORIAL SWELL TO 9 FT DOMINATES 
THE REMAINDER OF THE AREA S OF 17N BETWEEN 90W AND 130W AND S OF 
07N BETWEEN 78W AND 87W. THE COVERAGE OF THIS SWELL WILL NOT 
VARY MUCH THROUGH THE NEXT 48 HOURS. BROKEN TO OVERCAST 
STRATOCUMULUS CLOUDS BLANKET THE AREA N OF 13N W OF 115W.

$$
LEWITSKY