000
AXPZ20 KNHC 272155
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 07N78W TO 04N95W. THE ITCZ 
CONTINUES FROM 04N95W TO 10N110W TO BEYOND 07N140W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 30 NM S OF MONSOON TROUGH 
AXIS E OF 80W. SCATTERED MODERATE CONVECTION NOTED FROM 10N TO 
13N BETWEEN 107W TO 111W. SCATTERED MODERATE CONVECTION FROM 08N 
TO 11N BETWEEN 127W 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. 

AN AREA OF FRESH TO STRONG TRADE WINDS OFF THE NORTHERN COAST OF 
BAJA WILL DIMINISH AS WELL AS THROUGH TONIGHT THE 1028 MB HIGH 
PRES NEAR 33N130W 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 127W AND 130W. 
ADDITIONALLY A BROAD NEGATIVELY TILTED TROUGH ALOFT OVER THE 
ITCZ NEAR 115W IS SUPPORTING A WEAK SURFACE PERTURBATION ALONG 
THE ITCZ AND ADDITIONAL MODEST CONVECTION FROM 10N TO 13N 
BETWEEN 107W TO 111W. SIMILARLY AN UPPER TROUGH FROM NICARAGUA 
TO 05N95W IS SUPPORTING CLUSTERS OF CONVECTION ALONG THE MONSOON 
TROUGH S OF PANAMA AND COSTA RICA.

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.

$$
CHRISTENSEN