000
AXPZ20 KNHC 040330
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI JAN 04 2013

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...
MONSOON TROUGH FROM 09N79W TO 05N95W THEN ITCZ TO 08N104W TO 
06N114W TO 07N122W TO 05N140W.  ISOLATED MODERATE CONVECTION 
WITHIN 180 NM S OF AXIS E OF 90W.

...DISCUSSION...
BROAD UPPER LEVEL RIDGE COVERS WESTERN THIRD OF BASIN WITH 
MOSTLY DRY STABLE AIR MASS UNDER ITS CAP...POSSIBLE EXCEPTION IS 
70 KT JET CORE ADVECTING MOISTURE FROM 17N-21N W OF 125W.  LARGE 
AMPLITUDE UPPER LEVEL TROUGH DOWNSTREAM ALONG 116W EXTEND 
DRYNESS EASTWARD THROUGH REMAINDER OF BASIN WITH MINOR MOIST 
WITHIN 180 NM S OF MONSOON TROUGH E OF 90W.

...AT THE LOWER LEVELS...
DISSIPATING STATIONARY FRONT FROM 30N130W TO 26N140W LOST ITS 
UPPER LEVEL SUPPORT AND UNABLE TO SUSTAIN SIGNIFICANT WIND 
SPEEDS...ALTHOUGH NW SWELL TO 12 FT PROPAGATE SE TO THE EQUATOR 
W OF 110W.  A MORE VIGOROUS COLD FRONT PUSHING INTO NW CORNER 
OF BASIN LATE FRI BRINGS NEW ROUND OF STRONG NE BREEZE AND 16 FT 
NW SWELLS INTO E PAC FOR SAT AND SUN.

SURFACE HIGH PRES RIDGE EXTEND SW TO 21N118W.  PRES GRADIENT 
BETWEEN RIDGE AND ITCZ PROMPTS SMALL REGION OF FRESH NE TRADES 
FROM 08N TO 17N W OF 130W.  AREA OF TRADES INCREASE IN COVERAGE 
AS STRONG COLD FRONT MOVES E ALONG NORTHERN FRINGES OF BASIN AND 
A NEW AND STRONGER HIGH PRES MOVES INTO WESTERN HALF OF E PAC.  
NEW TRAIN OF NW SWELLS TO 16 FT SPREAD SE BEHIND COLD FRONT LATE 
IN FORECAST PERIOD. 

FRESH TO STRONG NORTHWESTERLY WINDS IN GULF OF CALIFORNIA N OF 
29N DIMINISH IN STRENGTH AND COVERAGE AS CURRENT HIGH PRES 
WEAKENS BY LATE FRI...BUT ARE REINFORCED BY NEW HIGH PRES AND 
SPREAD S TO 27N. 

GAP WINDS...GULF OF TEHUANTEPEC...NEXT GALE FORCE WIND EVENT  
STARTS TONIGHT AS NORTHERLY WINDS SURGE THROUGH CHIVELA PASS 
BEHIND GULF OF MEXICO COLD FRONT. GALE FORCE WINDS PULSE THROUGH 
SAT MORNING WITH STRONGEST WINDS LATE TONIGHT AND EARLY FRI.  
WIND DRIVEN SEAS BUILD TO 13 FT.

GULF OF PAPAGAYO...FRESH NE-E WINDS PULSE AGAIN TO STRONG EARLY 
FRI AS TRADES IN W CARIBBEAN SEA SHIFT W TOWARD CENTRAL AMERICA.

$$
WALLY BARNES