000
AXPZ20 KNHC 220354
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT DEC 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 06N77W TO 06N90W...THEN ITCZ 
FROM 06N90W TO 09N124W TO 07N140W. SCATTERED MODERATE CONVECTION 
EXISTS WITHIN 60 NM OF ITCZ BETWEEN 118W AND 132W AND AGAIN W OF 
137W.

...DISCUSSION...
A DYING FRONTAL BOUNDARY EXTENDS FROM CENTRAL CALIFORNIA TO 
25N136W. LARGE 15-18 SECOND NW SWELL ASSOCIATED WITH THE FRONT 
IS SWEEPING S OF 25N 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 15-20 FT 
TONIGHT AND ON SATURDAY OVER NORTHERN PORTION OF THE DISCUSSION 
AREA W OF 125W. THE INDIAN OCEANSAT SCATTEROMETER SHOWS ONLY 
MODERATE TO FRESH WINDS ALONG EITHER SIDE OF THE DISSIPATING 
FRONTAL BOUNDARY.

HIGH PRESSURE WILL BUILD EAST BEHIND THE FRONT ALONG 26N THROUGH 
MONDAY NIGHT.  THIS HIGH PRESSURE RIDGE WILL BECOME THE DOMINANT 
SYNOPTIC FEATURE ACROSS THE REGION SATURDAY THROUGH TUESDAY WITH 
LIGHT WINDS AND SEAS SUBSIDING FROM 12-15 FT TO ONLY 5-8 FT N OF 
22N BY CHRISTMAS DAY. THIS HIGH WILL ALSO SOMEWHAT ENHANCE NE-E 
TRADEWINDS S OF THE RIDGE AXIS AND N OF THE ITCZ. EXPECT FRESH 
TRADEWINDS FROM 10N TO 15N BETWEEN 120W-130W TONIGHT...THEN 
SPREADING ACROSS THE WATERS FROM 10N TO 20N W OF 125W BY LATE 
SATURDAY NIGHT THROUGH TUESDAY.  BY WEDNESDAY...A NEW COLD FRONT 
WILL REACH THE NORTHERN BOUNDARY...THOUGH THIS FEATURE AND ITS 
ASSOCIATED HIGH SEAS SHOULD NOT BE AS PRONOUNCED AS THE CURRENT 
EVENT.

GAP WINDS...
STRONG 1030 MB HIGH PRESSURE CENTERED OVER SE TEXAS BEHIND A 
COLD FRONT IS PRODUCING VERY STRONG GAP WIND EVENT THROUGH THE 
CHIVELA PASS INTO THE GULF OF TEHUANTEPEC.  AN 1856 UTC OCEANSAT 
OVERPASS INDICATED N WINDS REMAINING AT 50 KT.  THE SALINA CRUZ 
WEATHER STATION ALONG THE COAST OF THE GULF STILL IS REPORTING 
35 KT N WINDS AS OF 0200 UTC. MODEL GUIDANCE INDICATES WINDS 
WILL REMAIN AT OR NEAR STORM FORCE THROUGH LATE TONIGHT OR EARLY 
SATURDAY...WITH GALE CONDITIONS PERSISTING THROUGH LATE 
SATURDAY.  WIND-DRIVEN SEAS ARE QUICKLY FANNING OUTWARD FROM THE 
SOURCE REGION AS N-NE SWELL EXTENDING DOWNWIND FROM THE GULF OF 
TEHUANTEPEC TO NEAR 110W ARE MERGING WITH NW SWELL FROM THE 
DYING FRONT MENTIONED ABOVE.  LOOKING AHEAD...THE PRESSURE 
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 MONDAY...ALLOWING FOR WINDS TO 
DIMINISH TO 5-10 KT IN THE GULF OF TEHUANTEPEC ALONG WITH 3-5 FT 
SEAS BY MONDAY AFTERNOON.

INCREASED TRADEWIND FLOW IN THE SW CARIBBEAN WILL ALLOW WINDS IN 
THE GULF OF PAPAGAYO TO REACH 25-30 KT BY SATURDAY MORNING 
...WITH SEAS BUILDING TO 11-12 FT DOWNSTREAM FROM PAPAGAYO 
REGION SATURDAY.  AS IS TYPICAL...THIS EVENT IS STRONGEST IN 
LATE NIGHT-EARLY MORNING HOURS.  BY MONDAY...THE GAP WINDS IN 
THE GULF OF PAPAGAYO WILL RELAX TO PRIMARILY A FRESH WIND.  
FRESH NORTHERLY WINDS ARE ALSO POSSIBLE FARTHER S IN THE GULF OF 
PANAMA SATURDAY AND SUNDAY.

$$
LANDSEA