000
AXPZ20 KNHC 280342
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI DEC 28 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 08N83W TO 06N92W. THE ITCZ 
CONTINUES FROM 06N92W TO 10N120W TO BEYOND 08N140W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 90 NM N OF ITCZ AXIS BETWEEN 
125W AND 130W.

...DISCUSSION...

A 1028 MB CENTERED NEAR 33N130W WILL WEAKEN THROUGH TONIGHT 
AHEAD OF A COLD FRONT MOVING EASTWARD N OF 30N. AS A 
RESULT...THE AREA OF FRESH TO STRONG TRADES FROM 10N TO 20N W OF 
135W WILL CONTINUE TO SHRINK IN SIZE AS THE PRES GRADIENT 
LOOSENS. THIS WILL ONLY BE TEMPORARY HOWEVER AS STRONG HIGH PRES 
BUILDS FRI N OF 30N BEHIND THE EASTWARD BOUND FRONT...ALLOWING 
TRADE WINDS TO INCREASE AGAIN FROM 10N TO 20N...BUT FARTHER TO 
THE EAST MAINLY BETWEEN 115W AND 125W. 

SHIP OBSERVATIONS AND SCATTEROMETER DATA SHOW AN AREA OF FRESH 
TO STRONG TRADE WINDS OFF THE NORTHERN COAST OF BAJA ON THE 
EASTERN EDGE OF THE HIGH PRES. THESE WINDS WILL DIMINISH  
THROUGH TONIGHT AS HIGH PRES WEAKENS. RESIDUAL LONG PERIOD NW 
SWELL MIXED WITH FRESH NE SWELL WILL PERSIST FROM 10N TO 20N 
MAINLY W OF 120W. ANOTHER ROUND OF NW SWELL ORIGINATING OUT OF 
THE N CENTRAL PACIFIC WITH HEIGHTS OF 8 TO 11 FT AND PERIODS OF 
15 TO 20 SECONDS WILL PUSH SE THROUGH MOST OF THE AREA W OF 110W 
FROM EARLY FRI TO LATE SAT. THIS WILL MIX WITH THE RENEWED TRADE 
WIND FLOW TO ALLOW SEAS TO BUILD TO 8 TO 11 FT ONCE AGAIN IN THE 
AREA FROM 10N TO 20N W OF 130W BY LATE SAT.

MEANWHILE FAVORABLE JET DYNAMICS ALOFT ARE AIDING IN MODEST 
CONVECTION ALONG THE ITCZ FROM 08N TO 11N BETWEEN 125W AND 130W.

GAP WINDS...

WINDS WILL PULSE ACROSS THE GULF OF PAPAGAYO OVER THE NEXT 
COUPLE OF DAYS. WINDS WILL PEAK EACH NIGHT NEAR 25 KT DURING THE 
OVERNIGHT AND EARLY MORNING HOURS WITH THE ADDED COMPONENT OF 
NOCTURNAL DRAINAGE FLOW...THEN WILL DIMINISH BELOW 25 KT DURING 
THE AFTERNOON AND EARLY EVENING HOURS. 

GULF OF TEHUANTEPEC...LIGHT WINDS PREVAIL ACROSS THE GULF OF 
TEHUANTEPEC AFTER A COLD AIRMASS OVER THE GULF OF MEXICO 
MODIFIED AND SHIFTED EASTWARD. LOOKING FORWARD...ANOTHER COLD 
FRONT WILL MOVE ACROSS THE GULF OF MEXICO THIS WEEKEND. THIS 
WILL LEAD TO ANOTHER GAP WIND EVENT LIKELY STARTING SAT NIGHT. 
THIS GAP WIND EVENT IS EXPECTED TO BE STRONGER THAN THE ONE THAT 
JUST ENDED. A GALE WARNING HAS BEEN ISSUED FOR THE GULF OF 
TEHUANTEPEC FOR LATE SAT AS A RESULT.

$$
CHRISTENSEN