000
AXPZ20 KNHC 040941
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 4 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 
0900 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 09N77W TO 09N86W TO 06N91W. THE 
ITCZ CONTINUES FROM 06N91W TO 05N98W TO 07N107W TO 07N129W TO 
05N140W. NO SIGNIFICANT CONVECTION ALONG THE CONVERGENCE ZONE.

...DISCUSSION...
DISSIPATING STATIONARY FRONT FROM 32N130W TO 26N140W IDENTIFIED 
SOLELY BY WIND SHIFT AND LIGHT VARIABLE WINDS FROM SCATTEROMETER 
DATA. HIGH PRES CENTERED N OF THE AREA NEAR 38N129W IS WEAKENING.
COMBINED EFFECTS OF DISSIPATING FRONT AND WEAKENING RIDGE ACTING 
TO REDUCE PRESSURE GRADIENT ACROSS THE REGION WITH AREA OF FRESH 
NE TRADE WINDS SHRINKING TO SW PORTION OF FORECAST AREA N OF THE 
ITCZ...FROM 08N TO 17N W OF 130W. ASCAT SCATTEROMETER DATA SHOWS 
MODERATE TO FRESH TRADE WINDS IN AN AREA S OF 23N AND N OF A LINE
FROM 23N110W TO 10N116W TO 05N140W. EXPECT WEAKENING COLD FRONT N
OF THE AREA TO MOVE E INTO THE WEST COAST THROUGH SAT NIGHT. VERY
STRONG 1033-1034 MB HIGH PRES WILL BUILD W OF THE FRONT AND SHIFT
SLOWLY EASTWARD JUST N OF THE AREA THROUGH MON ROUGHLY ALONG 32N.
THE STRONG HIGH WILL SIGNIFICANTLY INCREASE THE PRES GRADIENT W 
OF 125W...WITH THE AREA OF FRESH TO STRONG NE WINDS N OF THE ITCZ
EXPANDING TO COVER AN AREA FROM 08N TO 25N W OF 125W BY SUN. NW 
SWELL GENERATED BY THE WEAKENING FRONT MOVING INTO THE WEST COAST
WILL REACH THE NW PORTION OF THE DISCUSSION AREA BY EARLY SAT 
MORNING...WITH SEAS BUILDING TO 13-14 FT W OF A LINE FROM 30N130W
TO 25N135W SAT THROUGH SUN...THEN SUBSIDE TO 11-12 FT MON. FRESH 
NW WINDS AROUND 20 KT WILL CONTINUE IN THE GULF OF CALIFORNIA 
THROUGH SUN...WITH SEAS TO 5 FT. 

GAP WINDS...
A GALE WARNING IS NOW IN EFFECT FOR THE GULF OF TEHUANTEPEC. HIGH
PRES BEHIND FRONTAL BOUNDARY IN THE SW GULF OF MEXICO WILL ALLOW 
WINDS FUNNELING THROUGH THE CHIVELA PASS TO REACH 30-35 KT NEAR 
THE COAST OF TEHUANTEPEC. ALTHOUGH THE AREA OF GALE FORCE WINDS 
WILL BE RELATIVELY SMALL AND ARE NOT EXPECTED TO EXTEND VERY FAR 
DOWNWIND FROM THE GULF OF TEHUANTEPEC...MODEL GUIDANCE INDICATES 
THE HIGH WIND EVENT WILL BE RELATIVELY LONG IN DURATION. EXPECT 
25-35 KT WINDS TO PULSE IN THE REGION N OF 14.5N BETWEEN 94W AND 
96W THROUGH SUN...WITH SEAS BUILDING TO 11 FT NEAR THE SOURCE 
REGION...THEN SPREADING OUT DOWNWIND...WITH 8-9 FT SEAS EXPECTED 
FROM 08N TO 13N BETWEEN 95W AND 105W THROUGH THE WEEKEND.

20-25 KT WINDS WILL CONTINUE TO PULSE DIURNALLY...WITH HIGHEST 
WINDS IN THE EARLY MORNING HOURS...NEAR THE GULF OF PAPAGAYO
FROM 10N TO 12N E OF 90W THROUGH SUN...WITH SEAS 8 FT OR LESS.

$$
MUNDELL