000
AXPZ20 KNHC 300321
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED NOV 30 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 
0130 UTC.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 06N90W TO LOW 
PRES NEAR 11N129W 1010 MB THEN ITCZ TO 09N140W. SCATTERED 
MODERATE CONVECTION LIES WITHIN 120 NM S AND 90 NM N OF AXIS W 
OF 137W. 

...DISCUSSION...

AN UPPER LOW LIES NEAR 27N138W. AN ASSOCIATED BROAD SURFACE 
TROUGH LIES N OF 15N BETWEEN 140W AND THE HAWAIIAN ISLANDS. THE 
1816 UTC ASCAT AND 1520 WINDSAT SCATTEROMETER PASSES SHOWED 
FRESH E FLOW OVER THE FAR W PORTIONS OF THE FORECAST AREA 
BETWEEN THE TROUGH AND 1035 MB SURFACE HIGH PRES CENTERED N OF 
THE AREA NEAR 42N138W AS WELL AS OVER WATERS BETWEEN THE HIGH 
AND 1010 MB LOW PRES ALONG THE MONSOON TROUGH/ITCZ NEAR 11N129W. 
THIS LOW PRES SYSTEM WILL BECOME ABSORBED INTO THE CONVERGENCE 
AXIS OVER THE NEXT 24 HOURS.

FURTHER E...A SHARP UPPER TROUGH EXTENDS FROM N CENTRAL MEXICO 
TO AN UPPER LOW NEAR 19N116W TO 00N114W. UPPER DIFFLUENCE ON THE 
E SIDE OF THE TROUGH IS ENHANCING ISOLATED MODERATE CONVECTION 
FROM 12N TO 20N 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 OVERNIGHT WED NIGHT. AN ASSOCIATED COLD FRONT WILL 
MOVE S OF 30N THU...EXTENDING FROM 30N111W TO 25N117W TO 26N130W 
TO 30N135W BY THU EVENING. THE FRONT WILL USHER IN FRESH TO 
STRONG NORTHERLY FLOW WITH N SWELL QUICKLY BUILDING SEAS TO 15 
FT IN WATERS BEHIND THE FRONT. 

GAP WINDS...
GULF OF TEHUANTEPEC...A REINFORCING SHORTWAVE TROUGH IS PUSHING 
SE THROUGH THE U.S. CENTRAL AND SOUTHERN PLAINS INTO THE 
BACKSIDE OF THE UPPER LOW CENTERED OVER THE EASTERN OHIO VALLEY. 
1027 MB HIGH PRES LIES NEAR 29N100W BEHIND THIS REINFORCING 
SHORTWAVE TROUGH. THE GRADIENT BETWEEN THIS INTENSIFIED HIGH 
PRES TO THE N AND LOWER PRES ASSOCIATED WITH THE MONSOON TROUGH 
TO THE S HAS ONCE AGAIN BROUGHT WINDS TO GALE FORCE IN THE GULF 
OF TEHUANTEPEC ACCORDING TO MODEL GUIDANCE. THE HIGH PRES WILL 
WEAKEN SLIGHTLY AS IT SINKS S WED AND THEN WEAKEN MORE RAPIDLY 
AS IT SHIFTS E OVERNIGHT WED NIGHT...WITH WINDS EXPECTED TO DROP 
BELOW GALE FORCE THU MORNING AFTER THE PEAK DRAINAGE FLOW 
DISSIPATES. 

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 AFOREMENTIONED HIGH PRES SYSTEM TO THE N SHIFTS EASTWARD 
ALLOWING THE PRES GRADIENT TO BECOME STRONGER OVER CENTRAL 
AMERICA BETWEEN THE HIGH AND DEVELOPING LOW PRES ALONG THE 
MONSOON TROUGH. A WEAK LOW IS EXPECTED TO DEVELOP NEAR 07N91W 
WED EVENING AND CONTINUE W AT 10 KT INTO THU EVENING.

GULF OF CALIFORNIA...STRONG SOUTHWESTERLY WINDS ARE EXPECTED TO 
DEVELOP 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. THE FRONT WILL CUT ACROSS THE GULF 
OF CALIFORNIA FROM 31N11W TO 28N113W BY THU EVENING.

$$
SCHAUER