000
AXPZ20 KNHC 251550
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN DEC 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA ACROSS PANAMA FROM 
09N78W TO 08N83W THEN DROPS SW TO 06N90W...THEN CONTINUING W TO  
07N105W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ 
AXIS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 30 NM EITHER SIDE OF A LINE FROM 06N94.5W TO 07.5N102W.
THE ITCZ AXIS FROM 07N105W TO 10N125W TO BEYOND 08N140W WITH AN 
EMBEDDED SURFACE TROUGH EXTENDING FROM 09N134W TO 16N132W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 
90 NM EITHER SIDE OF A LINE FROM 11N107W TO 08N115W TO 11N121W. 

...DISCUSSION...
AN UPPER CYCLONE IS CENTERED OVER EASTERN NEW MEXICO WITH ITS 
ENVELOPE OF CYCLONIC FLOW DOMINATING THE UPPER LEVELS N OF 24N E 
OF 103W AND IS ACCOMPANIED BY DRY UPPER AIR. AN UPPER TROUGH 
EXTENDS FROM 31N135W SW TO 23N140W...AND IS ALSO ACCOMPANIED BY 
DRY UPPER AIR. AN UPPER ANTICYCLONE IS CENTERED NEAR 11N109W 
WITH AN UPPER RIDGE EXTENDING NW TO BEYOND 32N128W. UPPER 
DIFFLUENCE HAS ENHANCED CONVECTION ALONG THE ITCZ BETWEEN 107W 
AND 121W AS PREVIOUSLY DESCRIBED. DENSE DEBRIS MOISTURE IS 
OBSERVED UNDER THE THE UPPER RIDGE...WITH SOME OF THE MOISTURE 
CONCENTRATING INTO A 420 NM WIDE PLUME EXTENDING FROM THE 
PACIFIC AT 18N120W TO OVER CENTRAL OLD MEXICO AT 26N102W...WITH 
THE MOISTURE CONTINUING NE ACROSS SE TEXAS...EVENTUALLY MERGING 
WITH A LARGE AREA OF UPPER MOISTURE SHIFTING E OVER THE SE 
UNITED STATES.   

ALTHOUGH A PAIR OF UPPER CYCLONES ARE CENTERED WELL S OF THE 
AREA OVER THE S PACIFIC NEAR 19S128W AND 22S140W...THEIR 
ENVELOPE OF UPPER CYCLONIC NW FLOW EXTENDS N OVER THE DISCUSSION 
AREA TO THE SW OF A LINE FROM 11N140W TO 00N120W. THIS HELPS SET 
UP THE AREA OF DIVERGENT FLOW TO THE NE LEADING INTO THE UPPER 
RIDGE AND THE ASSOCIATED DENSE UPPER MOISTURE JUST MENTIONED. AN 
UPPER CYCLONE IS OVER THE DEEP TROPICS AT 03N113W. FURTHER E AN 
UPPER ANTICYCLONE IS OVER NORTHERN S AMERICA WITH A RIDGE 
EXTENDING NW TO A CREST ALONG 12N96W TO BEYOND 24N94W. THE 
DEBRIS MOSITURE FROM THE CONVECTION ALONG THE MONSOON TROUGH 
EVAPORATES NEAR THE CONVECTIVE CLUSTERS AS THE UPPER LEVELS 
APPEAR DRY S OF 21N E OF 100W.

AT THE LOW LEVELS A SURFACE HIGH IS CENTERED NEAR 34N129W WITH 
HIGH PRESSURE DOMINATING THE MARINE AREA W OF 110W. A SURFACE 
COLD FRONT IS STALLING FROM 32N138W TO 30N142W. THE PRESSURE 
GRADIENT BETWEEN THE SURFACE TROUGH EMBEDDED IN THE ITCZ NEAR 
133W AND THE SURFACE HIGH OVER THE SUBTROPICS IS TIGHTENING AND 
EXPECT THE NORTHEASTERLY SURFACE WINDS CURRENTLY AT 20-25 KT IN 
THE AREA FROM 08N-23N W OF 112W TO INCREASE TO TO 25-30 KT W OF 
THE SURFACE TROUGH TONIGHT...AND MAINTAIN AS THE TROUGH SHIFTS W 
OF 140W ON TUE. NW SWELL IS MIXING WITH NE TRADE WIND SWELL OVER 
THE AREA N OF 10N W OF 110W...AND THE NW SWELL IS MIXING WITH 
CROSS EQUATORIAL SE SWELL IN THE WATERS S OF 10N W OF 118W.

GULF OF CALIFORNIA...NW WINDS AT 20-25 KT ARE FORECAST IN THE 
GULF WATERS S OF 30N THROUGH TONIGHT...THEN THE WINDS WILL 
GRADUALLY DIMINISH TO 20 KT IN THE AREA S OF 28N BY EARLY TUE.  

GULF OF TEHUANTEPEC...NORTHERLY WINDS AT 20-30 KT THIS MORNING 
ARE EXPECTED TO INCREASE TO GALE FORCE THIS AFTERNOON AND 
CONTINUE THROUGH EARLY MON...DIMINISHING BELOW GALE LATE MON.
OVERNIGHT DRAINAGE EFFECTS WILL ALLOW WINDS TO SURGE TO 30 KT ON 
TUE AND WED MORNINGS...BUT GENERALLY THE N WINDS WILL CONTINUE 
TO GRADUALLY DIMINISH THROUGH MIDWEEK.

GULF OF PAPAGAYO...FRESH TRADEWINDS OVER THE WESTERN CARIBBEAN 
WILL FUNNEL INTO AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO
THROUGH TUE MORNING.

$$
CHRISTENSEN