000
AXPZ20 KNHC 110939
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT DEC 11 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS 04N77W TO 06N86W TO 
09N116W THEN RESUMES AT 08N122W TO 08N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS FROM 08N TO 11N BETWEEN 115W AND 
121W...AND WITHIN 90 NM S OF AXIS FROM 122W TO 128W. 

...DISCUSSION...
A 1026 MB SURFACE HIGH PRES CENTERED NEAR 32N129W EXTENDS A 
RIDGE OVER THE FORECAST WATERS TO THE SE TO 18N112W AND TO THE 
SW BEYOND 18N140W. THE PRESSURE GRADIENT BETWEEN THE HIGH 
PRESSURE AND LOWER PRESSURE NEAR THE ITCZ IS SUPPORTING FRESH 
TRADE WINDS FROM 08N TO 25N W OF 122W. SOME SHIP OBSERVATIONS 
AND A RECENT ASCAT PASS CONFIRMED THE PRESENCE OF THESE WINDS.  
THE FRESH TRADES WILL PERSIST ACROSS THIS AREA OVER THE NEXT 24 
HOURS...THEN WILL DECREASE IN AREAL EXTENT THROUGH 48 HOURS AS 
THE HIGH PRESSURE CENTER SHIFTS NE. SE TO S WINDS IN THE 20 TO 
25 KT RANGE ARE ALSO NOTED N OF 25N AND W OF 130W BETWEEN THE 
WESTERN PERIPHERY OF THE HIGH PRES AND A COLD FRONT LOCATED W OF 
AREA. THIS COLD FRONT WILL CLIP THE FAR NW PORTION OF AREA ON 
SUN AND GRADUALLY DISSIPATED THROUGH LATE MON.

LONG PERIOD NW SWELL...WAVE PERIODS BETWEEN 14 TO 16 SECONDS... 
WITH SIGNIFICANT WAVE HEIGHTS OF 10 TO 12 FT CONTINUES TO 
PROPAGATE SE ACROSS MOST OF THE REGIONAL WATERS W OF 110W. THE 
SWELL WILL SUBSIDE TO 8 TO 10 FT IN ABOUT 24-36 HOURS...BUT 
EXTEND FURTHER EAST REACHING NEAR 100W.  

GAP WINDS...
THE MOST RECENT ASCAT PASS...0408 UTC...INDICATED 20 KT WINDS IN 
THE GULF OF TEHUANTEPEC. NWP MODELS SUGGEST THESE WINDS SHOULD 
DECREASE TO LESS THAN 20 KT WITHIN THE NEXT 12 HOURS. FRESH  
WINDS OVER THE WESTERN CARIBBEAN ARE FUNNELING THROUGH THE 
CENTRAL AMERICA PASSES RESULTING IN FRESH WINDS OVER THE GULFS 
OF PAPAGAYO...AND PANAMA. WINDS OVER THE WESTERN CARIBBEAN WILL 
DIMINISH FROM WEST TO EAST...WHICH WILL LEAD TO WINDS 
DIMINISHING BELOW 20 KT FOR THE GULF OF PAPAGAYO IN 18 
HOURS...AND THE GULF OF PANAMA IN 24 HOURS. 

LOOKING AHEAD...ANOTHER TEHUANTEPEC EVENT WILL BE INDUCED BY A 
STRONG COLD FRONT MOVING ACROSS THE GULF OF MEXICO THIS WEEKEND. 
COLD AIR ADVECTION IN THE WAKE OF THE FRONT WILL FUNNEL TROUGH 
THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC STARTING SUN 
NIGHT. ACCORDING TO THE COMPUTER MODELS...ANOTHER GALE FORCE 
WIND EVENT COULD TAKE PLACE. AS A RESULT...GALE WARNING HAS BEEN 
ISSUED. BASED ON THE MARINE GUIDANCE...WINDS ARE EXPECTED TO 
REACH 40 KT WITH SEAS BUILDING TO AROUND 16 FT. EXPECT ALSO 
INCREASING WINDS AND SEAS ACROSS THE GULFS OF FONSECA AND 
PAPAGAYO MON NIGHT AS A RIDGE OF HIGH PRES STRENGTHENS OVER THE 
WESTERN CARIBBEAN.

$$
GR