000
AXPZ20 KNHC 122141
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON SEP 12 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...
MONSOON TROUGH HAS REALIGNED DUE TO TROPICAL WAVE ACROSS CENTRAL 
AMERICA AND EXTENDS FROM NEAR 13N88W TO 09.5N101W TO 1012 MB LOW 
PRES AT 11.5N107W TO 1013 MB LOW PRES AT 17N118W TO 09.5N124W 
WHERE IT TRANSITIONS TO ITCZ TO WEAKENING 1012 MB LOW PRES AT 
11N138W TO BEYOND 08N140W. SCATTERED MODERATE CONVECTION IS 
NOTED ALONG THE MONSOON TROUGH AXIS FROM 08N TO 13N BETWEEN 91W 
AND 94W. ISOLATED MODERATE CONVECTION IS FROM 08N TO 10N BETWEEN 
99W AND 102W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 10N 
BETWEEN 107W AND 110W. 

...DISCUSSION...

AT THE SURFACE...A WEAK HIGH PRES RIDGE CONTINUES JUST N OF THE 
NW WATERS PRODUCING MAINLY LIGHT TO MODERATE NE TRADEWINDS. A 
STATIONARY FRONT IS FURTHER W EXTENDING SW FROM 32N143W TO 
30N147W. 

A 1013 MB LOW IS CENTERED OVER SW ARIZONA NEAR 33N114W. 
A SURFACE TROUGH EXTENDS S FROM THE LOW TO THE GULF OF 
CALIFORNIA AT 26N110W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE 
TROUGH. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ALONG THE COAST 
OF S MEXICO WITHIN 30 NM EITHER SIDE OF LINE 22N106W TO 16N110W 
DUE TO PORTIONS OF REMNANTS OF T.S. NATE.

BROAD CYCLONIC FLOW AROUND A TROPICAL WAVE CURRENTLY OVER THE NW 
CARIBBEAN HAS INDUCED NELY FLOW OVER THE SOUTHERN GULF OF 
MEXICO. THIS FLOW IS FUNNELING THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC...RESULTING IN FRESH 20 KT WINDS. GUIDANCE 
SUGGESTS WINDS WILL INCREASE ACROSS THE GULF OF TEHUANTEPEC TO 
25 KT TONIGHT.

THE THREE LOW PRESSURE AREAS THAT ARE EMBEDDED WITHIN THE 
MONSOON TROUGH MENTIONED ABOVE CONTINUE TO SLOWLY WEAKEN AND ARE 
EXPECTED TO DISSIPATE WITHIN THE NEXT 48 HOURS.

20 KT NW WINDS ARE W OF BAJA CALIFORNIA N OF 27N E OF 117W. 
ELSEWHERE...CROSS EQUATORIAL SW SWELL WITH SEAS TO 9 FT ARE OVER 
MUCH OF THE AREA S OF 10N BETWEEN 94W AND 124W. THIS SWELL EVENT 
WILL CONTINUE TO SPREAD NORTHWARD THROUGH THE FORECAST PERIOD 
REACHING THE COAST OF MEXICO S OF SOUTHERN BAJA CALIFORNIA 
TONIGHT.

$$
FORMOSA