000
AXPZ20 KNHC 292153
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE NOV 29 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 06N90W TO LOW 
PRES NEAR 11N128W 1011 MB THEN BECOMES ITCZ TO 09N140W. 
SCATTERED MODERATE CONVECTION LIES WITHIN 90 NM S AND 150 NM N 
OF THE AXIS W OF 137W. ISOLATED MODERATE CONVECTION LIES N OF 
THE AXIS TO 19N BETWEEN 105W AND 115W.

...DISCUSSION...

AN UPPER LOW IS CENTERED NEAR 27N140W WITH A TROUGH EXTENDING SW 
TO 20N144W. AN ASSOCIATED BROAD SURFACE TROUGH LIES WELL W OF 
THE AREA ALONG 150W. THE 1816 UTC ASCAT AND 1520 WINDSAT 
SCATTEROMETER PASSES ALONG WITH SHIP DATA FROM THE PAST 6 HOURS 
SHOWED FRESH E FLOW OVER MUCH OF THE AREA BETWEEN THE TROUGH 
AND 1034 MB SURFACE HIGH PRES CENTERED N OF THE AREA NEAR 
39N136W....INCLUDING MUCH OF WESTERN WATERS N OF THE ITCZ. 

FURTHER E...A SHARP UPPER TROUGH EXTENDS FROM N CENTRAL MEXICO 
TO AN UPPER LOW NEAR 19N116W TO 00N116W WITH A WEAK SURFACE 
TROUGH REFLECTED ALONG 111W S OF 15N TO THE MONSOON TROUGH. 
UPPER DIFFLUENCE ON THE E SIDE OF THE TROUGH IS ENHANCING 
ISOLATED MODERATE CONVECTION N OF THE MONSOON TROUGH TO 19N 
BETWEEN 105W AND 115W. WHILE WINDS ARE GENERALLY LIGHT TO 
MODERATE NEAR THE TROUGH...HIGHER WINDS TO 20 KT LIKELY CONTINUE 
IN THE VICINITY OF THE THUNDERSTORMS. 

LOOKING AHEAD...AN UPPER TROUGH WILL DIG INTO SOUTHERN 
CALIFORNIA OVER THE NEXT 36 TO 48 HOURS. AN ASSOCIATED COLD 
FRONT WILL MOVE S OF 30N...EXTENDING FROM 30N116W TO 26N120W TO 
30N135W BY THU AFTERNOON. THE FRONT WILL USHER IN FRESH TO 
STRONG NORTHERLY FLOW WITH N SWELL QUICKLY BUILDING SEAS TO 15 
FT OVER THE WATERS BEHIND THE FRONT. 

GAP WINDS...
GULF OF TEHUANTEPEC...GALE FORCE WINDS HAVE BRIEFLY ABATED AS 
HIGH PRES HAS BECOME MORE BROAD BEHIND THE COLD FRONT OVER THE 
NW CARIBBEAN. REINFORCING SHORTWAVE ENERGY ALOFT WILL BRIEFLY 
AMPLIFY THE TROUGHING OVER THE GULF TONIGHT. THIS ALONG WITH 
DRAINAGE EFFECTS IS EXPECTED TO MAINTAIN GALE CONDITIONS THROUGH 
THE GULF OF TEHUANTEPEC OVERNIGHT TONIGHT. THE AIRMASS WILL 
MODIFY TO THE NORTH THROUGH WED...ALLOWING THE GALES TO DIMINISH 
BY WED AFTERNOON. 

GULF OF PAPAGAYO...STRONG GRADIENT FLOW OVER THE WESTERN 
CARIBBEAN THAT HAS ALLOWED WINDS TO PULSE IN EXCESS OF 20 KT 
THROUGH THE GULF OF PAPAGAYO DURING THE LATE NIGHT AND EARLY 
MORNING HOURS SHOULD BECOME MORE SUSTAINED ON WED NIGHT AND THU 
AS THE INFLUENCE OF THE AFOREMENTIONED REINFORCING TROUGHING 
OVER THE GULF OF MEXICO REACHES CENTRAL AMERICA. 

GULF OF CALIFORNIA...SOUTHWESTERLY WINDS ARE EXPECTED TO 
INCREASE TO 20 TO 25 KT OVERNIGHT WED NIGHT AS A DEEP LAYER 
TROUGH DIGS INTO SOUTHERN CALIFORNIA. THE ASSOCIATED COLD FRONT 
WILL REACH THE NORTHERN GULF OF CALIFORNIA THU...WITH FRESH TO 
STRONG WINDS SHIFTING NW BEHIND THE FRONT. 

$$
SCHAUER/CHRISTENSEN