000
AXPZ20 KNHC 230402
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN DEC 23 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 06N83W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N83W TO 
07N110W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 120 NM N OF ITCZ W OF 120W.

...DISCUSSION...

THE LONG-PERIOD LARGE NW SWELL EVENT CONTINUES TO DOMINATE THE 
SURFACE CONDITIONS.  A 2200 UTC ALTIMETER PASS SAMPLED LARGE NW 
SWELL UP TO 16 FT ALONG THE N BORDER OF THE DISCUSSION AREA 
ALONG 132W...A COUPLE FT HIGHER THAN THE GFS-BASED WAVEWATCH. 
THIS SET OF HIGH ENERGY NW SWELL HAS PEAK WAVE PERIODS OF 18-20 
FT. THE SWELL WILL GRADUALLY DECAY TO A COMBINED MAXIMUM OF 
ABOUT 14 FT IN 24 HOURS...WITH SEAS OF 8 FT OR GREATER REACHING 
THE EQUATOR ALSO IN ABOUT A DAY. 

A 1022 MB HIGH HAS BECOME ESTABLISHED AT 26N141W WITH RIDGING 
EXTENDING EAST-WEST FROM THE HIGH. THIS HIGH AND ACCOMPANYING 
RIDGE WILL BECOME THE DOMINANT SYNOPTIC FEATURE ACROSS THE 
REGION SATURDAY THROUGH TUESDAY WITH GENERALLY LIGHT TO MODERATE 
WINDS ACROSS THE NORTHERN WATERS. THE HIGH WILL ALSO ENHANCE NE 
TRADES S OF THE RIDGE AXIS AND N OF THE ITCZ. TRADES ARE ALREADY 
20-25 KT IN THE W CENTRAL WATERS AS INDICATED BY RECENT ASCAT 
AND OCEANSAT SCATTEROMETER PASSES. THE SHIFTING RIDGE TO THE E 
WILL HELP TO EXPAND THE TRADES TO 120W IN ABOUT 24 HOURS WHILE 
COMBINED SEAS WILL REMAIN 12-14 FT IN MIXED NE WIND WAVES AND 
THE NW SWELL SET ACROSS THE AREA OF ENHANCED TRADES.

AS THE RIDGE CONTINUES TO BUILD EASTWARD IN THE WAKE OF THE 
TROUGH...A TIGHT PRESSURE GRADIENT WILL ALSO SET UP NEAR THE 
BAJA CALIFORNIA PENINSULA WITH INVERTED TROUGHING LOCATED NEAR 
THE W COAST OF MEXICO. THIS MAY INDUCE NW TO N WINDS OF 20-25 KT 
WITHIN 120-180 NM W OF THE BAJA CALIFORNIA PENINSULA BY MONDAY 
MORNING.

GAP WINDS...
A 1027 MB HIGH PRESSURE CENTERED OVER THE N CENTRAL GULF OF 
MEXICO BEHIND A STRONG COLD FRONT CONTINUES TO FORCE A GAP WIND 
EVENT THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC.  
THE SALINA CRUZ MEXICAN WEATHER STATION ALONG THE COAST OF THE 
GULF REPORTS 25 KT N WIND AT 0200 UTC...BUT NO OBSERVATIONS ARE 
AVAILABLE OVER THE GULF ITSELF.  IT IS LIKELY THAT 35-40 KT GALE 
CONDITIONS STILL ARE PRESENT THIS EVENING.  HIGH SEAS OF UP TO 
ABOUT 17 FT ARE EMANATING FROM THE SOURCE REGION OF THE GULF OF 
TEHUANTEPEC WITH N-NE SWELL EXTENDING TO NEAR 113W. THESE SWELLS 
ARE MERGING WITH NW SWELL FROM THE NORTHERN PORTION OF THE 
DISCUSSION AREA NOTED ABOVE. THE PRESSURE GRADIENT IS FORECAST 
TO RELAX SIGNIFICANTLY OVER THE REGION LATE IN THE WEEKEND INTO 
EARLY NEXT WEEK WITH WINDS DIMINISHING BELOW GALE FORCE BY 
MID-DAY SUNDAY...THEN TO 20 KT OR LESS BY LATE SUNDAY NIGHT. 
LOOKING AHEAD...A WEAKER COLD FRONT MAY MOVE THROUGH THE SW GULF 
OF MEXICO WEDNESDAY ALLOWING FOR A SHORT-LIVED MINIMAL GALE 
FORCE WIND EVENT IN THE GULF OF TEHUANTEPEC BEHIND ITS PASSAGE 
TO THE N BEGINNING WEDNESDAY AFTERNOON.

INCREASED TRADES IN THE SW CARIBBEAN IS AIDING NE-E 20-25 KT 
WINDS IN THE GULF OF PAPAGAYO THIS EVENING...AS SEEN BY AN 
EARLIER OCEANSAT SCATTEROMETER PASS. THE WINDS SHOULD CONTINUE 
WITH LITTLE CHANGE THROUGH EARLY MONDAY. SEAS HAVE BUILT UP TO 
ABOUT 12 FT MAXIMUM AS OBSERVED BY AN ALTIMETER PASS AROUND 1900 
UTC. WINDS AND SEAS WILL SUBSIDE BY LATE MONDAY AS THE 
TRADES IN THE CARIBBEAN BACK OFF.

A QUITE SHORT-LIVED WIND EVENT TO A PEAK OF 25 KT N WINDS IN THE 
GULF OF PANAMA IS ANTICIPATED TO BEGIN SHORTLY AND DIMINISH BY 
SUNDAY AFTERNOON.

$$
LANDSEA