000
AXPZ20 KNHC 152118
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC SUN DEC 15 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 
2030 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC...A 1542 UTC ASCAT SCATTEROMETER PASS SHOWED 
NORTHERLY WINDS UP TO 40 KT IN THE NORTHERN GULF OF TEHUANTEPEC 
WHERE WINDS HAVE LIKELY SINCE INCREASED UP TO 45 KT. SEA SURFACE 
TEMPERATURES MEASURED BY THE GOES SATELLITE WERE WELL OVER 25 
CELSIUS IN THE AREA AND THE COLD AIR MASS MOVING OVER THE WARM 
SEA SURFACE SHOULD PROMOTE VERTICAL MIXING THAT SHOULD ALLOW THE 
STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. WINDS ARE 
FORECAST TO REACH STORM FORCE BY 00 UTC MON...PERSISTING AT 
STORM FORCE THROUGH MON MORNING. WINDS WILL THEN DIMINISH BACK 
TO GALE FORCE THROUGH TUE. SEAS WILL QUICKLY BUILD TO UP TO 20 
FT DURING THE STORM FORCE WINDS...AND AN IMPRESSIVE PLUME OF NE 
SWELL FROM THE EVENT WILL PROPAGATE WELL SW OF TEHUANTEPEC... 
WITH THE AREA FROM 03N TO 14N BETWEEN 92W AND 110W EXPECTED TO 
SEE 8-11 FT SEAS IN MIXED NE AND SW SWELL BY 48 HOURS.
 
GULF OF CALIFORNIA...MORNING AND EARLY AFTERNOON SCATTEROMETER 
PASSES MISSED THE MAJORITY OF THE GULF OF CALIFORNIA WHERE GALE 
FORCE WINDS ARE LIKELY STILL OCCURRING N OF 29N WITHIN 45 NM OF 
THE BAJA CALIFORNIA PENINSULA...WITH FRESH TO STRONG NORTHERLY 
WINDS ELSEWHERE IN THE GULF N OF 24N W OF 110W. WINDS SHOULD 
DIMINISH BELOW GALE FORCE LATE TONIGHT...THEN QUICKLY DIMINISH 
TO 20 KT OR LESS BY LATE MON AFTERNOON AS THE PRESSURE GRADIENT 
LOOSENS. SEAS UP TO 10 FT WILL SUBSIDE TO LESS THAN 8 FT BY LATE 
MON AFTERNOON AS WELL. ALSO...FRESH TO STRONG WINDS ARE BLOWING 
THROUGH NORTHERN BAJA GAPS INTO THE E PACIFIC WATERS FROM 28.5N 
TO 30N WITHIN 45 NM OF THE PENINSULA. THESE GAP WINDS WILL 
DIMINISH BY EARLY MON.

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

THE MONSOON TROUGH EXTENDS FROM 10N83W TO 06N104W TO 09N116W   
TO 07N127W. THE ITCZ EXTENDS FROM 07N127W TO BEYOND 08N140W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 120 
NM S OF THE AXIS BETWEEN 83W AND 85W...AND ALSO WITHIN 120 NM 
EITHER SIDE OF THE AXIS BETWEEN 111W AND 117W.

...DISCUSSION... 

ELSEWHERE AT THE SURFACE...1033 MB HIGH PRESSURE IS TO THE W OF 
NORTHERN CALIFORNIA NEAR 39N133W WITH A RIDGE EXTENDING TO THE 
SE THROUGH 32N126W TO 15N108W. RECENT ASCAT-B SCATTEROMETER DATA 
SHOWED AN AREA OF FRESH TO STRONG TRADES FROM 19N TO 24N BETWEEN 
128W AND 136W WHERE SEAS ARE 9-11 FT IN MIXED SE AND NW SWELL. 
THE AREA OF TRADES IS FORECAST TO WEAKEN AND SHRINK AS THE 
DRIVING HIGH PRESSURE CENTER SHIFTS NORTHWARD...WEAKENING THE 
PRESSURE GRADIENT BETWEEN IT AND THE ITCZ/MONSOON TROUGH AXIS. 

THIS AREA OF WINDS IS SURROUNDED BY AND MIXING WITH LONG PERIOD 
NW SWELL AS WELL AS LONG PERIOD CROSS-EQUATORIAL SOUTHERLY 
SWELL. THE RESULT IS COMBINED SEAS OF 8-11 FT ROUGHLY N OF 
09N/10N AND W OF 110W-115W. THE AREA OF SEAS OF 8 FT OR GREATER 
WILL SHIFT TO THE SE WHILE GRADUALLY SUBSIDING THROUGH THE DAY 
TUE.
       
GULF OF PAPAGAYO...LATE MORNING ASCAT DATA SHOWED MAINLY 
MODERATE NE WINDS IN THE GULF OF PAPAGAYO...HOWEVER WINDS WILL 
INCREASE TO FRESH TO STRONG LEVELS BUILDING SEAS TO UP TO 8 FT 
DURING THE MAXIMUM NOCTURNAL DRAINAGE THROUGH THE END OF THE 
FORECAST PERIOD TUE MORNING. NE SWELL FROM PAPAGAYO WILL COMBINE 
WITH NW SWELL FROM THE GULF OF TEHUANTEPEC TO BRING SEAS TO 9 FT 
BETWEEN 88W AND 92W BY TUE. 
 
$$
LEWITSKY