000
AXPZ20 KNHC 212135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE DEC 21 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 02N78W TO LOW 
PRES 07N92W TO 08N110W TO 10N125W TO 07N140W. SCATTERED MODERATE 
FROM 08N TO 10N BETWEEN 120W AND 127W. 

DISCUSSION...
A WEAKENING COLD FRONT EXTENDS SW FROM NEAR TIJUANA MEXICO TO 
21N130W THEN WSW TO 19N140W. AN ASCAT PASS FROM 1810 UTC SHOWED 
20 TO 25 KT W TO NW WINDS BEHIND THE COLD FRONT PARTICULARLY N 
OF 27N. A DEEP LAYER TROUGH SUPPORTS THIS FRONT. A SECONDARY 
FRONT WILL FOLLOW AND CLIP THE N WATERS. THIS SECOND FRONT IS 
EXPECTED TO OVERTAKE THE DISSIPATING FRONT NEAR NORTHERN BAJA 
CALIFORNIA WED EVENING. SEAS BEHIND THE FRONT WILL BUILD TO 
ABOUT 16 FT IN LONG PERIOD NW SWELL BUT ARE EXPECTED TO SUBSIDE 
TO ABOUT 10 FT BEFORE REACHING BAJA CALIFORNIA. THE FRONT WILL 
MOVE THROUGH THE NORTHERN GULF OF CALIFORNIA THU...WITH S WINDS 
INCREASING TO 20 TO 25 KT AHEAD THE FRONT OVER THE GULF WATERS N 
OF 29N. THE AXIS OF A DENSE MOISTURE PLUME ORIGINATING IN THE 
CENTRAL PACIFIC STREAMING ACROSS THE DISCUSSION AREA INTO THE SW 
CONUS IS FROM 19N140W TO 23N125W TO BEYOND 32N115W. 

A SURFACE TROUGH WITHIN THE ITCZ EXTENDS FROM 16N121W TO 
09N125W. A DIFFLUENT PATTERN ALOFT IS HELPING TO INDUCE 
CONVECTION NEAR THE TROUGH AXIS. A WEAK 1010 MB LOW PRES IS ALSO 
WITHIN THE ITCZ NEAR 07N92W DRIFTING WWD. 

CROSS EQUATORIAL SE WINDS ARE EXPECTED TO SPREAD N ACROSS THE 
EQUATOR OVER THE PACIFIC WATERS S OF 07N W OF 125W IN 24 HOURS 
AND ARE FORECAST TO COVER THE AREA W OF 120W IN ABOUT 48 HOURS. 
   
GAP WINDS...
AN ASCAT PASS FROM THIS MORNING INDICATED NE WINDS OF 20 TO 25 
KT ACROSS THE GULF OF PAPAGAYO WHILE THE EDGE OF WINDSAT PASS 
SHOWED N WINDS OF 20 TO 25 KT THROUGH THE GULF OF PANAMA. 
SOME LATE NIGHT DRAINAGE FLOW IS EXPECTED MAINTAIN 20 KT N WINDS 
IN THE GULF OF TEHUANTEPEC AROUND SUNRISE THROUGH FRI. 

LOOKING AHEAD...ACCORDING TO THE COMPUTER MODELS...A GALE FORCE 
WIND EVENT WILL TAKE PLACE ACROSS THE GULF OF TEHUANTEPEC SAT 
NIGHT. 
     
$$
GR/DM