000
AXPZ20 KNHC 180954
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 09N84W TO 06N92W THEN ITCZ TO 05N105W TO 
10N124W TO 07N140W.  ISOLATED MODERATE CONVECTION WITHIN 45 NM 
OF AXIS FROM 109W TO 111W.

...DISCUSSION...

SHARP NEGATIVE TILTED UPPER LEVEL TROUGH EXTENDS FROM 32N132W TO 
DEVELOPING CYCLONE NEAR 28N129W.  GUIDANCE MOVES WEAK CYCLONE 
ACROSS NORTHERN EDGE OF BASIN INTO N BAJA CALIFORNIA LATE SUN... 
BUT HAS SECOND AND MUCH INTENSE CYCLONE MOVING E ACROSS 140W 
LATE IN FORECAST PERIOD.  DEEPENING SECOND CYCLONE SUPPORTS 1002 
MB LOW PRES AND ATTENDANT STRONG COLD FRONT ENTERING BASIN SUN 
WITH STRONG TO NEAR GALE FORCE S-SW WINDS WELL AHEAD OF BOUNDARY 
AND SIMILAR N-NE WINDS W OF FRONT.  PLENTY OF MOISTURE AVAILABLE 
WITH BOTH CYCLONES AND UPPER LEVEL DIVERGENT FLOW E OF THEM 
EXPECTED TO BRING SERIOUS CONVECTION INTO REGION AROUND NORTHERN 
BAJA CALIFORNIA...MAINLY WITH SECOND ONE.  

ELSEWHERE AT THE LOWER LEVELS...
HIGH PRES CENTER WELL N OF E PAC HAS RIDGE EXTEND S-SW THROUGH 
32N130W TO 20N135W.  RIDGE GIVES WAY AS COLD FRONT ACROSS 140W 
INTO BASIN SUN WITH AFOREMENTIONED WINDS AND SEAS BUILDING TO 
ABOVE 20 FT IN NW SWELL SPREADING EVEN S OF EQUATOR.  LARGE VERY 
LONG PERIOD NW SWELL...WELL ABOVE 20 SECONDS...SPREAD SE ACROSS 
BASIN DOMINATING HEIGHTS W OF 110W BY END OF FORECAST. 
  
GULF OF TEHUANTEPEC CONTINUES TO BE AFFECTED BY WINDS CROSSING 
ISTHMUS FROM GULF OF MEXICO.  PRESENTLY STORM FORCE WINDS TO 50 
KT HAVE BEEN OBSERVED WITH SEAS OVER 20 FT.  WHILE WINDS ARE 
EXPECTED TO DIMINISH TEMPORARILY LATE IN THE PERIOD...THEY 
REMAIN AT GALE FORCE THROUGH BEYOND MON.  SWELLS SPREAD S AND W 
OF REGION 10N AND 105W.  

STRONG TO NEAR GALE FORCE WINDS OVER SW CARIBBEAN PROMPT STRONG 
NE BREEZE ACROSS GULF OF PAPAGAYO AND FRESH N BREEZE OVER GULF 
OF PANAMA THROUGH FORECAST PERIOD.  E SWELLS FROM GULF OF 
PAPAGAYO MERGE WITH NE SWELLS FROM GULF OF TEHUANTEPEC BUILDING 
SEAS IN LARGE AREA DOWNWIND FROM BOTH THROUGH ENTIRE FORECAST 
PERIOD.

$$
WALLY BARNES