000
AXPZ20 KNHC 190945
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU DEC 19 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 
0945 UTC.

...SPECIAL FEATURE...
 
GULF OF TEHUANTEPEC...MINIMAL GALE CONDITIONS ARE EXPECTED TO 
DIMINISH TO 20 TO 30 KT BY SUNRISE THIS MORNING. MAXIMUM SEAS
ARE CURRENTLY AT 13 FT DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
AND WILL GRADUALLY SUBSIDE TO LESS THAN 8 FT BY THIS EVENING.
THE NEXT NORTHERLY SURGE WILL BEGIN LATE SUN NIGHT REACHING 
GALE FORCE BY SUNRISE ON MON. THIS WILL LIKELY BE ANOTHER STRONG
GALE EVENT AND PERSIST THROUGH WED EVENING.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS W ACROSS THE CARIBBEAN ALONG 10N FROM 
THE COLOMBIAN COAST AT 10N75W TO THE PACIFIC COAST OF COSTA RICA 
AT 10N85W...THEN DIPS SW TO 06N92W THEN W TO 06N101W WHERE 
SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ 
CONTINUES W TO BEYOND 08N140W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE
ITCZ WITHIN 180 NM EITHER SIDE OF A LINE FROM 06N101W TO 10N137W.
   
...DISCUSSION... 

GULF OF PAPAGAYO...NE-E WINDS WILL PULSE AT 20-25 KT DURING THE 
MAXIMUM NOCTURNAL DRAINAGE EARLY THIS MORNING AND AGAIN FRI NIGHT
THROUGH SUNRISE ON SAT. THE NE SWELL PROPAGATING SW FROM THE 
GULF OF PAPAGAYO WILL MIX WITH LONG PERIOD CROSS-EQUATORIAL 
SWELL...RESULTING IN COMBINED SEAS OF 6-9 FT AS FAR S AS 07N96W 
THIS AFTERNOON. EXPECT THE NOCTURNAL MAX TO ONLY REACH 15-20 KT 
ON SAT NIGHT INTO SUN MORNING. GUIDANCE SUGGESTS THE 20-25 KT 
DRAINAGE WILL OCCUR AGAIN LATE MON NIGHT. 

A SURFACE RIDGE EXTENDS FROM 32N140W TO 20N105W WITH NE 20-25 KT 
TRADES BETWEEN THE RIDGE AND ITCZ ACROSS THE WATERS W OF 127W. 
LONG PERIOD NW SWELL IS MIXING WITH THE ASSOCIATED NE TRADE WIND 
SWELL...AND ALSO WITH LONG PERIOD CROSS-EQUATORIAL SOUTHERLY 
SWELL...RESULTING IN COMBINED SEAS OF 7-10 FT WITHIN THIS AREA. 
THE GRADIENT WILL RELAX SOME IN THIS AREA BY FRI.

A COLD FRONT IS APPROACHING THE NORTHERN PORTION OF THE BAJA 
CALIFORNIA PENINSULA WITH POST-FRONTAL HIGH PRESSURE ALREADY 
SUPPORTING NORTHERLY 20-25 KT WINDS ACROSS THE DISCUSSION AREA N 
OF 30N BETWEEN 120-130W. NORTHERLY WINDS AT 20-25 KT...SEAS 8-14 
FT...ARE EXPECTED TO SPREAD S ACROSS THE DISCUSSION AREA N OF 
25N TONIGHT. THE GRADIENT WILL BEGIN TO RELAX ON FRI AS THE 
FRONT PASSES THROUGH THE GULF OF CALIFORNIA. THE NORTHERLY WINDS 
WILL DIMINISH TO 15-20 KT ACROSS THE DISCUSSION AREA W OF A LINE 
FROM THE CENTRAL BAJA CALIFORNIA PENINSULA TO 09N140W THIS 
EVENING. MIXED N SWELL WILL ALSO MIX WITH LONG PERIOD CROSS 
EQUATORIAL SE SWELL...WITH COMBINED SEAS OF 7-13 FT IN THIS AREA 
THIS EVENING. THE NORTHERLY SWELL WILL GRADUALLY SUBSIDE OVER 
THE UPCOMING WEEKEND WITH SEAS OF 8-9 FT ONLY EXPECTED ACROSS 
THE TROPICAL WATERS W OF 118W ON MON.  
     
GULF OF CALIFORNIA...SOUTHERLY WINDS ARE CURRENTLY AT 10-15 KT 
ACROSS THE NORTHERN GULF WATERS. THESE SOUTHERLY WINDS SHOULD 
SOON INCREASE TO 20-25 KT AHEAD OF A PRE-FRONTAL TROUGH ARRIVING 
THIS AFTERNOON FOLLOWED BY A COLD FRONT TONIGHT. THE WINDS WILL 
DIMINISH TO 10-15 KT EITHER SIDE OF THE FRONT ON FRI. THE FRONT 
SHOULD REACH AS FAR S AS 27N ON FRI EVENING...AND MOVE E OF THE 
GULF WATERS BY SAT MORNING. THE GRADIENT WILL INCREASE 
SUPPORTING NW WINDS OF 15-20 KT ACROSS THE ENTIRE GULF OF 
CALIFORNIA ON SUN EVENING...FURTHER INCREASING TO 20-25 KT ON 
SUN NIGHT INTO MON.
 
$$
NELSON