000
AXPZ20 KNHC 212145
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED DEC 21 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...
MONSOON TROUGH AXIS EXTENDS FROM 08N82W TO 06N90W TO 07N97W. 
ITCZ AXIS EXTENDS FROM 07N97W TO 10N112W. THE ITCZ THEN 
CONTINUES FROM 10N116W TO 06.5N135W TO 08N140W. NO SIGNIFICANT 
CONVECTION WAS NOTED.

...DISCUSSION...
SURFACE RIDGING PREVAILS OVER MUCH OF THE NORTHERN HALF OF THE 
FORECAST. THE PRES GRADIENT BETWEEN THIS RIDGING AND LOWER 
PRESSURE IN THE VICINITY OF THE ITCZ IS MAINTAINING A LARGE AREA 
OF FRESH TRADE WINDS THAT EXTENDS AS FAR E AS 110W. THIS AREA OF 
HIGH PRESSURE WILL PREVAIL OVER THE N PART OF THE AREA THROUGH 
THU...MAINTAINING THIS AREA OF TRADE WINDS. HIGH PRESSURE WILL 
FURTHER BUILD N OF THE AREA FURTHER TIGHTENING THE PRESSURE 
GRADIENT BY FRIDAY. THIS WILL STRENGTHEN OF THE TRADEWINDS...AS 
WELL AS INCREASE THE AREAL COVERAGE OF FRESH TO STRONG 
TRADEWINDS BY FRI. 

CONTINUED CONVECTION AND ASSOCIATED LATENT HEAT RELEASE OVER THE 
PAST 24 HOURS HAS HELPED FOR THE DEVELOPMENT OF A SURFACE TROUGH 
FROM 13N113W TO 09N116W. SCATTERED TO NUMEROUS MODERATE TO 
STRONG CONVECTION WAS NOTED WITHIN 180 NM EITHER SIDE OF THE 
TROUGH AXIS.

GAP WINDS...
GULF OF PAPAGAYO...FRESH TRADEWINDS OVER THE WESTERN CARIBBEAN 
CONTINUE TO FUNNEL INTO THE GULF OF PAPAGAYO.  THESE WINDS WILL 
BE STRONGEST IN THE EARLY MORNING HOURS WITH THE ASSISTANCE OF 
DRAINAGE FLOW OFF THE LAND. THE WINDS OVER THE GULF OF PAPAGAYO 
ARE EXPECTED TO DIMINISH BELOW 20 KT THU AFTERNOON. 

GULF OF CALIFORNIA...HIGH PRES BUILDING IN THE GREAT BASIN OF 
THE CONUS WILL DRIVE NW TO N WINDS IN THE GULF OF CALIFORNIA N 
OF 29N BY THU EVENING. THESE WINDS WILL INCREASE TO GALE FORCE 
OVER THE GULF OF CALIFORNIA N OF 24N BY EARLY FRI. 

$$
AL