000
AXPZ20 KNHC 140403
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI DEC 14 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 
0330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS W FROM THE W COLOMBIAN COAST AT 
10N76W ACROSS THE PANAMA AND COSTA RICA BORDER TO 10N85W...THEN 
SW TO 06N97W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN 
ITCZ THAT EXTENDS W0NW TO BEYOND 09N140W. ISOLATED MODERATE TO 
STRONG CONVECTION IS OBSERVED FROM 05-09N TO THE E OF 92W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 60 NM EITHER SIDE OF A 
LINE 08N127W TO 09N140W.  

...DISCUSSION...

ALOFT...A LONGWAVE TROUGH IS OVER THE WESTERN SEABOARD OF N 
AMERICA WITH ITS MEAN AXIS EXTENDING S INTO THE DISCUSSION AREA 
FROM 32N119W TO 20N127W...ACCOMPANIED BY DRY UPPER AIR TO THE N 
OF 22N W OF 118W. A BROAD UPPER TROUGH IS NOTICED TO THE S OF 
15N ALONG 119W. AN UPPER RIDGE EXTENDS E INTO THE AREA FROM 
08N140W TO 01N123W. AN UPPER ANTICYCLONE IS AT 11N90W WITH A 
RIDGE EXTENDING SW TO 06N114W. STRONG UPPER WESTERLIES CONTINUE 
TO ADVECT A 700 NM WIDE PLUME OF UPPER MOISTURE E ACROSS THE 
TROPICS TO ALONG 125W WHERE SOME OF THE MOISTURE TURNS SE AROUND 
THE WESTERN TROPICAL RIDGE BUT EVAPORATES BEFORE REACHING THE
EQUATOR. THE REMAINING MOISTURE TURNS NE AS IT PASSES E OF THE 
UPPER TROUGH...AND FANS OUTS AS IT CONTINUES E ACROSS THE 
SOUTHERN BAJA PENINSULA...ACROSS MOST OF NORTHERN OLD MEXICO... 
AND NOW OVER SOUTHERN NEW MEXICO AND PORTIONS OF TEXAS.

A BROAD INVERTED UPPER TROUGH IS OBSERVED OVER THE DEEP TROPICS 
TO THE S OF 09N ALONG 100W AND IS PROGRESSING WESTWARD. UPPER 
DIFFLUENCE JUST S OF THE EASTERN TROPICAL RIDGE IS ENHANCING THE 
ISOLATED MODERATE TO STRONG CONVECTION ALONG THE MONSOON TROUGH 
AS PREVIOUSLY DESCRIBED...WITH THE RESULTANT THIN DEBRIS 
MOISTURE ADVECTED NE ACROSS THE RIDGE AXIS...AND OVER CENTRAL 
AMERICA TO THE E OF 90W. 

LOW LEVELS...A COLD FRONT EXTENDS SW OVER THE N PORTION OF THE 
BAJA CALIFORNIA PENINSULA SW TO 21N129W. SOUTHWESTERLY WINDS 
HAVE INCREASED TO 20-25 KT TO THE N OF 27N EASTWARD TO THE BAJA 
PENINSULA...WITH SEAS OF 5-6 FT. ALTHOUGH NW WINDS ARE ONLY AT 
15-20 KT TO THE N OF 24N W OF THE FRONT...NW SWELLS RESULT IN 
COMBINED SEAS OF 8-11 FT. NE TRADES CONTINUE AT 20-25 KT WITH 
SEAS TO 9 FT ACROSS THE WATERS FROM 10-24N W OF 130W. THE FRONT 
WILL WEAKEN TO A FRONTAL TROUGH AS IT PASSES ACROSS THE BAJA 
PENINSULA EARLY FRI. THE NW SWELL WILL SUBSIDE ON SAT WITH 
SEAS AT 8-10 FT ACROSS THE WATERS N OF 25N TO THE E OF 133W. THE 
AREA OF NE 20-25 KT TRADES WILL EXTEND FROM 12-24N TO THE W OF 
130W WITH SEAS 7-10 FT. THE N SWELLS RESULTING IN SEAS TO 8 FT 
WILL PROPAGATE SE ACROSS THE WATERS ELSEWHERE NW OF LINE FROM 
THE BAJA PENINSULA AT 112W TO 10N140W.
 
GENERALLY EXPECT SEAS TO BUILD TO 5-8 FT IN THE NW SWELL TONIGHT 
ACROSS THE WESTERN BAJA COASTAL WATERS TO THE N OF 27N. 
SOUTHWESTERLY 20-25 KT WINDS CURRENTLY ACROSS THE GULF OF 
CALIFORNIA TO THE N OF 28N WILL SPREAD S TO ALONG 25N ON FRI 
THEN DIMINISH TO TO 10-15 KT BEHIND THE DISSIPATING COLD FRONT.  
     
GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS EXPECTED AT 20-30 KT EARLY TONIGHT 
WILL WILL QUICKLY DIMINISH ON FRI. BEST GUESS IS THE NEXT 
NORTHERLY EVENT WILL BEGIN LATE TUE NIGHT...PEAKING 25 KT.

GULF OF PAPAGAYO...NE WINDS WILL CONTINUE TO PULSE AT 15-20 KT 
WITH AN OCCASIONAL SURGES TO 20-25 KT TONIGHT THEN DIMINISH TO 
15-20 KT ON FRI.

$$
NELSON