000
AXPZ20 KNHC 032203
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JAN 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 07N77W TO 08N91W TO 07N99W THEN ITCZ TO 
06N133W TO 04N140W.  SCATTERED MODERATE CONVECTION WITHIN 210 NM 
S OF AXIS E OF 89W.

...DISCUSSION...
BROAD UPPER LEVEL RIDGE COVERS WESTERN THIRD OF BASIN WITH 
MOSTLY DRY STABLE AIR MASS UNDER ITS CAP...POSSIBLE EXCEPTION IS 
WEAK 55 KT JET CORE ADVECTING MOISTURE FROM 17N-22N W OF 127W.  
DOWNSTREAM...LARGE AMPLITUDE UPPER LEVEL TROUGH EXTEND DRYNESS 
EASTWARD THROUGH REMAINDER OF BASIN WITH MINOR MOIST WITHIN 210 
NM OF MONSOON TROUGH E OF 89W.

...AT THE LOWER LEVELS...
DISSIPATING STATIONARY FRONT FROM 30N129W TO 27N140W LOST ITS 
UPPER LEVEL SUPPORT AND UNABLE TO SUSTAIN SIGNIFICANT WIND 
SPEEDS...ALTHOUGH NW SWELL TO 13 FT PROPAGATE SE TO THE EQUATOR 
W 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 CENTER 1025 MB AT 31N125W HAS RIDGE EXTEND SW 
TO 11N123W.  PRES GRADIENT BETWEEN RIDGE AND ITCZ PROMPTS FRESH 
NE TRADES FROM 06N TO 23N W OF 128W.  AREA OF TRADES INCREASE IN 
COVERAGE AS STRONG COLD FRONT MOVES E ALONG NORTHERN FRINGES OF 
BASIN AND NEW AND STRONGER HIGH PRES MOVES INTO WESTERN HALF OF 
E PAC.  NEW TRAIN OF NW SWELLS TO 15 FT SPREAD SE BEHIND COLD 
FRONT LATE IN THE FORECAST PERIOD. 

FRESH TO STRONG NORTHWESTERLY WINDS IN GULF OF CALIFORNIA N OF 
28N DIMINISH IN STRENGTH AND COVERAGE AS CURRENT HIGH PRES 
WEAKENS BY LATE FRI.

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