000
AXPZ20 KNHC 252117
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 07N81W TO 06.5N103W. THE 
ITCZ AXIS EXTENDS FROM 06.5N103W TO 10N126W TO BEYOND 08N140W. 
SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 180 NM 
N OF AXIS BETWEEN 108W AND 120W. 

...DISCUSSION...

HIGH PRES 1033 MB IS CENTERED N OF THE AREA NEAR 37N137W WITH 
RIDGE EXTENDING SE TO NEAR 20N110W. THE PRESSURE GRADIENT 
BETWEEN THIS AREA OF HIGH PRESSURE AND LOWER PRESSURE IN THE 
VICINITY OF THE ITCZ IS MAINTAINING FRESH TO STRONG TRADEWINDS 
AS INDICATED BY RECENT ASCAT PASSES. A SURFACE TROUGH EXTENDS 
FROM 08N135W TO 18N132W. THE SURFACE TROUGH WILL INTERACT WITH 
AN UPPER TROUGH TO THE NW AND AMPLIFY AS IT GRADUALLY SHIFTS W 
OF 140W THROUGH 48 HOURS. THIS WILL LOCALLY TIGHTEN THE PRES 
GRADIENT BETWEEN THE TROUGH AND RIDGE OF HIGH PRESSURE...AND 
INCREASE WINDS TO 25 KT TO 30 KT W OF THE TROUGH. NE FLOW TO 20 
KT CONTINUES TO BREACH GAPS OVER THE BAJA CALIFORNIA PENINSULA 
AN INTO THE ADJACENT PACIFIC WATERS. THIS LOCALIZED GAP FLOW 
WILL DIMINISH THROUGH MON AS WINDS OVER THE THE GULF OF 
CALIFORNIA CONTINUE TO DIMINISH.

GULF OF CALIFORNIA...NW WINDS OF 20 TO 25 KT CONTINUES OVER THE 
GULF WATERS AS DEPICTED BY LATEST ASCAT PASS. THESE WINDS ARE 
FORECAST TO GRADUALLY DIMINISH TO 20 KT IN THE AREA S OF 27N BY 
MON AFTERNOON.  

GULF OF TEHUANTEPEC...NORTHERLY WINDS AT 20-30 KT PREVAIL OVER 
THE GULF WATERS. WINDS ARE EXPECTED TO INCREASE TO GALE FORCE 
THIS EVENING. WINDS ARE THEN EXPECTED TO DIMINISH BELOW GALE 
FORCE LATE MON AFTERNOON AS THE AIRMASS TO THE N MODIFIES. THE 
GALE FORCE WINDS WILL GENERATE A PLUME NE SWELL WITH HEIGHTS 
GREATER THAN 8 FT REACHING AS FAR W AS 110W THROUGH 48 HOURS

GULF OF PAPAGAYO...FRESH TRADEWINDS OVER THE WESTERN CARIBBEAN 
WILL FUNNEL INTO THE GULF OF PAPAGAYO. WINDS WILL PEAK DURING 
THE EARLY MORNING HOURS WITH THE ADDITION OF NOCTURNALLY DRIVEN 
KATABATIC WINDS.

$$
AL