000
AXPZ20 KNHC 211539
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI DEC 21 2012

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 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 08N78W TO 06N91W...THEN ITCZ 
FROM 06N91W TO 09N117W TO 07N140W. NO SIGNIFICANT CONVECTION.

...DISCUSSION...
A DYING COLD FRONT EXTENDS FROM SAN FRANCISCO BAY TO 25N140W. 
LARGE NW SWELL ASSOCIATED WITH THE FRONT IS SWEEPING S OF 30N 
INTO THE TROPICS...AND WILL CONTINUE TO PROPAGATE SOUTHWARD INTO 
THE SOUTHERN HEMISPHERE THROUGH CHRISTMAS DAY AND SLOWLY DECAY. 
COMBINED SEAS AROUND 12-15 FT ALONG LEADING EDGE OF THE SWELL 
TRAIN WILL PEAK AT 17-19 FT TONIGHT OVER NORTHERN PORTION OF THE 
DISCUSSION AREA W OF 125W. SCATTEROMETER SHOWS MODERATE TO FRESH 
WINDS ALONG EITHER SIDE OF THE DISSIPATING FRONTAL BOUNDARY.

HIGH PRESSURE WILL BUILD EAST BEHIND THE FRONT ALONG 26N THROUGH 
MON NIGHT. A RIDGE ALONG 26N WILL BECOME THE DOMINANT SYNOPTIC 
FEATURE ACROSS THE REGION SAT THROUGH TUE WITH LIGHT WINDS AND 
SEAS SUBSIDING FROM 15-17 FT TO ONLY 6-8 FT N OF 22N BY CHRISTMAS
DAY. THIS HIGH WILL ALSO ENHANCE NE-E TRADE WINDS S OF THE RIDGE 
AXIS AND N OF THE ITCZ. EXPECT FRESH TO STRONG TRADE WINDS FROM 
10N TO 15N BETWEEN 120W-130W TONIGHT...THEN SPREADING ACROSS THE 
WATERS FROM 10N TO 20N W OF 125W BY LATE SAT NIGHT. 

GAP WINDS...
STRONG 1033 MB HIGH PRES CENTERED OVER SOUTH TEXAS BEHIND A COLD 
FRONT IS PRODUCING VERY STRONG GAP WIND EVENT THROUGH THE CHIVELA
PASS INTO THE GULF OF TEHUANTEPEC. OSCAT PASS AT 0640 UTC SHOWED 
50 KT WINDS ALONG THE EDGE OF THE SWATH...AND A SHIP REPORTED 35 
KT WINDS NEAR 13.6N 94.1W AT 1200 UTC. MODEL GUIDANCE INDICATES 
WINDS WILL REMAIN AT OR NEAR STORM FORCE THROUGH LATE TONIGHT OR 
EARLY SAT...WITH GALE CONDITIONS PERSISTING THROUGH EARLY SUN. 
WIND-DRIVEN SEAS WILL QUICKLY FAN OUTWARD FROM THE SOURCE REGION 
AS N-NE SWELL EXTENDING DOWNWIND FROM THE GULF OF TEHUANTEPEC TO 
NEAR 110W...MERGING WITH NW SWELL FROM THE DYING FRONT MENTIONED 
ABOVE. LOOKING AHEAD...THE PRES GRADIENT IS EXPECTED TO RELAX 
SIGNIFICANTLY OVER THE REGION BY EARLY NEXT WEEK WITH SOUTHERLY 
FLOW BECOMING ESTABLISHED IN THE SW GULF OF MEXICO BY EARLY 
MON...ALLOWING FOR WINDS TO DIMINISH TO 5-10 KT IN THE GULF OF 
TEHUANTEPEC ALONG WITH 3-5 FT SEAS BY MON AFTERNOON.

INCREASED TRADE WIND FLOW IN THE SW CARIBBEAN WILL ALLOW WINDS 
IN THE GULF OF PAPAGAYO TO REACH 25-30 KT BY SAT MORNING...WITH 
SEAS BUILDING TO 11-12 FT DOWNSTREAM FROM PAPAGAYO REGION SAT.  
FRESH NORTHERLY WINDS ARE ALSO POSSIBLE FURTHER S IN THE GULF OF 
PANAMA LATE SAT NIGHT AND SUN MORNING.

$$
MUNDELL