000
AXPZ20 KNHC 181605
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED DEC 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...
 
GULF OF TEHUANTEPEC GALE...NORTHERLY GALE FORCE WINDS ARE 
EXPECTED TO PERSIST INTO TONIGHT...THEN DIMINISH TO 20 TO 30 KT 
EARLY THU MORNING. THE MAXIMUM SEAS ARE CURRENTLY AT 15 FT 
DOWNSTREAM OF THE GULF OF TEHUANTEPEC AND WILL GRADUALLY SUBSIDE 
TO LESS THAN 8 FT THU EVENING.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 09N77W 1009 MB TO 
07N79W TO 08.5N84.5W TO 06N97W...WHERE IT TRANSITIONS TO 
ITCZ...08.5N120W TO BEYOND 06N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION NOTED WITHIN 150 NM EITHER SIDE OF TROUGH E OF 
90W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM 
EITHER SIDE OF ITCZ BETWEEN 115W AND 136W. 
   
...DISCUSSION... 

A SURFACE RIDGE EXTENDS FROM A 1032 MB HIGH NEAR 36N145W SE TO 
NEAR 22N114W WITH AN AREA OF NE 20 KT TRADES LOCATED BETWEEN THE 
RIDGE AND THE ITCZ...GENERALLY S OF 18N AND W OF 118W. 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 7-9 FT WITHIN THE AREA 
FROM 08-16N. THE GRADIENT WILL TIGHTEN THROUGH TONIGHT WITH NE-E 
TRADES OF 15-25 KT ENHANCED ACROSS THE DISCUSSION WATERS FROM 08-
20N W OF 130W YIELDING SEAS 7-9 FT TONIGHT INTO THU.  

GULF OF PAPAGAYO...NE-E WINDS WILL PULSE AT 20-25 KT DURING THE 
MAXIMUM NOCTURNAL DRAINAGE TONIGHT THROUGH FRI NIGHT...THEN MAX 
AT 15-20 KT ON SAT NIGHT. 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 
07.5N96W ON THU AFTERNOON. EXPECT THE NOCTURNAL MAX TO ONLY 
BRIEFLY REACH 15-25 KT ON SAT NIGHT INTO SUN MORNING...AND THEN 
DIMINISH TO LESS THAN 20 KT SUN NIGHT AS A COLD FRONT MOVES 
ACROSS THE GULF OF MEXICO. 

A COLD FRONT WILL APPROACH THE NORTHERN PORTION OF THE BAJA 
CALIFORNIA PENINSULA TONIGHT. STRENGTHENING HIGH PRESSURE IN THE 
WAKE OF THE FRONT WILL SUPPORT NORTHERLY 20-25 KT WINDS ACROSS 
THE DISCUSSION AREA N OF 25N ON THU NIGHT WITH SEAS BUILDING TO 
16 FT NEAR 30N124W. 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 
115W ON SAT...WHILE LARGE NORTHERLY SWELL WILL PROPAGATE 
SOUTHWARD TO 20N ON SAT. 
 
GULF OF CALIFORNIA...NW WINDS ARE CURRENTLY AT 10-15 KT 
THROUGHOUT MOST OF THE ENTIRE LENGTH OF THE GULF WATERS...AND  
ARE EXPECTED TO DIMINISH TO 5-10 KT ACROSS N PORTIONS THIS 
MORNING...THEN BECOME SOUTHERLY LATER TODAY. THE SOUTHERLY WINDS 
WILL INCREASE OVER THE NORTHERN GULF WATERS LATE TONIGHT INTO 
EARLY THU AHEAD OF A PRE-FRONTAL TROUGH ARRIVING ON THU 
AFTERNOON...FOLLOWED BY A COLD FRONT ON THU NIGHT. THE FRONT 
SHOULD REACH AS FAR S AS 27N ON FRI NIGHT ACCOMPANIED BY A SW TO 
W TO NW WIND SHIFT AT AROUND 10-15 KT.  

$$
STRIPLING