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000
AXPZ20 KNHC 180333
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU DEC 18 2014

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC.


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

THE MONSOON TROUGH EXTENDS W FROM THE PACIFIC COAST OF COLOMBIA NEAR 05N77W TO 07N90W TO 05N95W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ WHICH WIGGLES W BETWEEN 05-07N TO BEYOND 140W. CONVECTION IN THE MONSOON TROUGH REGION... SCATTERED MODERATE FROM 02N-07N E OF 82W AND FROM 04N-08N BETWEEN 90W AND 96W. CONVECTION IN THE ITCZ REGION...SCATTERED MODERATE FROM 04N-06N BETWEEN 112W AND 116W AND FROM 06N-09N W OF 129W.


...DISCUSSION...

AN UPPER-LEVEL LONGWAVE TROUGH PREVAILS OVER THE WESTERN PORTION OF THE DISCUSSION AREA WITH ITS MEAN AXIS EXTENDING SW FROM 32N120W TO 20N125W TO 14N135W. AN EMBEDDED SHORTWAVE TROUGH IS MOVING THROUGH THE LONGWAVE PATTERN PRECEDED BY UPPER MOISTURE THAT IS CURRENTLY MOVING ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA AND GULF OF CALIFORNIA. ANOTHER DENSE PLUME OF UPPER MOISTURE ORIGINATES FROM ITCZ CONVECTION WEST OF 130W...AND CONTINUES NE ACROSS THE DISCUSSION AREA WITHIN 260 NM EITHER SIDE OF A LINE FROM 10N130W TO ACROSS CENTRAL MEXICO... EVENTUALLY FANNING OUT ACROSS THE SE CONUS. AN ASSOCIATED WEAK SURFACE TROUGH IS FROM 32N115W TO 30N115W...WITH ONLY NW WINDS OF 5-15 KT BEHIND ITS AXIS. HOWEVER...LONG PERIOD NW SWELL CONTINUES TO MIX WITH LONG PERIOD SOUTHERLY SWELL ACROSS THE ENTIRE OPEN WATERS WATERS W OF 106W. A POST-FRONTAL RIDGE IS BUILDING E FROM 28N138W TO 27N119W. A SLIGHTLY STRONGER PRESSURE GRADIENT BETWEEN THE RIDGE AND THE ITCZ IN THE TROPICS IS SUSTAINING NE TRADES OF 20-25 KT FROM 08N TO 16N W OF 126W. THESE CONDITIONS ARE FORECAST TO SPREAD E TO ALONG 125W OVER THE NEXT TWO TO THREE DAYS.

GULF OF TEHUANTEPEC...NE WINDS HAVE DIMINISHED TO 10-15 KT... BUT THE NE SWELL IS MIXING WITH LONG PERIOD CROSS EQUATORIAL SWELL RESULTING IN A NARROW BAND OF SEAS OF 6-8 FT SW OF THE GULF OF TEHUANTEPEC WITHIN 60 NM EITHER SIDE OF A LINE FROM 13N96W TO 12N99W TO 12N101W. THESE ENHANCED SEAS WILL CONTINUE SW AND GRADUALLY SUBSIDE BELOW 8 FT BY FRIDAY MORNING.

GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED THROUGH EARLY FRI.

GULF OF CALIFORNIA...LIGHT AND VARIABLE WINDS ARE EXPECTED TO BECOME NW AT 10-15 KT LATE THU...THEN GRADUALLY INCREASE TO 15- 20 KT BY EARLY FRI...THEN CONTINUING THROUGH THE WEEKEND.

$$ RAMOS/NELSON

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