000
AXPZ20 KNHC 012203
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JAN 1 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 EXTENDS FROM 07N78W TO 10N109W THEN ITCZ FROM 
09N117W TO 07N120W TO 05N140W.  ISOLATED MODERATE CONVECTION 
WITHIN 90 NM OF AXIS FROM 96W TO 103W AND W OF 135W.

...DISCUSSION...
BROAD SUBTROPICAL RIDGE WITH AXIS ALONG 138W HAS CREST FLATTENED 
BY INCOMING DEEP LAYER TROUGH PRESENTLY W OF AREA.  JET CORE OF 
75 KT BRINGS MOISTURE INTO NW CORNER OF BASIN AS COLD FRONT 
SUPPORTED BY DEEP LAYER TROUGH ENTER E PAC.  NEVERTHELESS...WELL 
ANCHORED RIDGE HOLDS ITS GROUNDS AND TROUGH SHIFTS NE STALLING 
COLD FRONT ALONG 30N130W TO 22N140W.  STRONG WINDS ASSOCIATED 
WITH COLD FRONT DIMINISH BY THU...BUT LARGE 13-17 FT LONG PERIOD 
NW SWELLS PROPAGATE INTO E PAC TO 110W.  

LARGE AMPLITUDE UPPER LEVEL TROUGH EXTEND FROM 32N114W TO 
00N135W EXTENDING THE DRY AIR MASS REGION UNDER UPSTREAM RIDGE 
FARTHER E TO 115W.  

...ELSEWHERE AT THE LOWER LEVELS...
HIGH PRES CENTER 1026 MB AT 31N129W MAINTAINS TIGHT PRES 
GRADIENT WITH WEAK SURFACE TROUGH OVER ARIZONA TO THE W AND ITCZ 
TO THE S TO PROMPT FRESH TO STRONG NW WINDS OVER GULF OF 
CALIFORNIA N OF 26N AND FRESH TRADE WINDS FROM 07N TO 23N W OF 
130W.

GAP WINDS...
GULF OF TEHUANTEPEC...MODEL GUIDANCE POINT TO A RETURN OF STRONG 
TO NEAR GALE FORCE N WINDS ACROSS GULF OF TEHUANTEPEC STARTING 
WED NIGHT AND INCREASING...POSSIBLY TO GALE FORCE...BY END OF 
FORECAST PERIOD.

GULF OF PAPAGAYO...FRESH E-NE BREEZE EXPECTED EARLY MORNINGS 
THROUGH FRI...BUT SEAS SHOULD REMAIN BELOW 8 FT.  SWELL 
GENERATED BY PREVIOUS STRONG WINDS HAVE SPREAD W AWAY FROM  
SOURCE REGION...PRESENTLY NOTED FROM 99W TO 110W...SUBSIDING 
BELOW 8 FT BY LATE THU.

GULF OF CALIFORNIA...HIGH PRES BUILD OVER BASIN PLUS LOW PRES 
TROUGH OVER ARIZONA ALLOW FOR FRESH TO STRONG NW WINDS IN GULF 
OF CALIFORNIA N OF 26N TONIGHT THEN PERSIST WITH LITTLE CHANGE 
THROUGH THU.

$$
WALLY BARNES