000
AXPZ20 KNHC 271505
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 08N78W TO 05N87W WHERE LOW LEVEL 
WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS TO 08N111W TO 
BEYOND 06N140W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 
WITHIN 120 NM N OF AXIS BETWEEN 106W AND 113W.

...DISCUSSION...

HIGH PRESSURE 1028 MB IS CENTERED N OF THE AREA NEAR 35N132W 
WITH RIDGE EXTENDING SE TO NEAR 21N108W. THE PRESSURE GRADIENT 
BETWEEN THIS AREA OF HIGH PRESSURE AND LOWER PRESSURE IN THE 
VICINITY OF THE ITCZ IS MAINTAINING FRESH TO STRONG TRADEWINDS 
FROM 10N TO 18N W OF 130W. THE PRESSURE GRADIENT BETWEEN THE 
RIDGE AND A TROUGH OF LOW PRESSURE OVER MEXICO IS SUPPORTING 
FRESH TO STRONG NW WINDS OFF THE COAST OF BAJA CALIFORNIA N OF 
28N. THOUGH IT WILL WEAKEN SOMEWHAT...THE RIDGE WILL REMAIN 
THROUGH THE FORECAST PERIOD. THIS WILL MAINTAIN THE AREA OF 
FRESH TO STRONG TRADEWINDS...BUT IT WILL LOOSEN THE PRESSURE 
GRADIENT ENOUGH TO DIMINISH WINDS BELOW ADVISORY CRITERIA OFF 
THE COAST OF BAJA CALIFORNIA.

MUCH OF THE AREA N OF 10N W OF 125W AREA DOMINATED BY NW SWELLS 
IN THE 8 TO 11 FT RANGE. THIS SWELL WILL SLOWLY SUBSIDE WHILE 
SPREADING S AND E OVER THE NEXT COUPLE OF DAYS. BY SAT 
MORNING...NW SWELLS WITH SEAS AT LEAST 8 FT WILL COVER MUCH OF 
THE AREA N OF 10N W OF 110W. A NEW SET OF NW SWELLS WILL ENTER 
THE NW PART OF THE FORECAST AREA FRI...WITH SEAS INCREASING TO 
11 FT OVER THIS AREA BY FRI NIGHT BEFORE STARTING TO SUBSIDE.  

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...WINDS HAVE DIMINISHED BELOW GALE FORCE 
OVER THE GULF OF TEHUANTEPEC THIS MORNING. WITH FLOW VEERING IN 
THE GULF OF MEXICO...WINDS FUNNELING THROUGH THE CHIVELA PASS 
WILL CONTINUE TO DECREASE. THIS WILL HELP DIMINISH WINDS BELOW 
25 KT BY THIS AFTERNOON. 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.

$$
AL