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Eastern Pacific Tropical Weather Discussion (Text)

000
AXPZ20 KNHC 110930
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1005 UTC WED DEC 11 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 
0930 UTC.

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC...NORTHERLY WINDS ARE FUNNELING THROUGH THE 
CHIVELA PASS INTO THE GULF OF TEHUANTEPEC AND HAS TRIGGERED THE 
MOST RECENT GALE EVENT. A 0546 UTC OSCAT PASS INDICATED WINDS OF 
30-40 KT WITHIN 30 NM OF A  LINE FROM 16N95W TO 14N96W WITH SEAS 
BUILDING TO 10 TO 15 FT. THESE WINDS MAY INCREASE SLIGHTLY OVER 
THE NEXT FEW HOURS WITH THE ONSET OF DIURNALLY ENHANCED 
NOCTURNAL DRAINAGE FLOW. MARGINAL GALE CONDITIONS ARE EXPECTED 
TO PERSIST FOR THE REMAINDER OF THE DAY AND INCREASE TO 40 KT OR 
SO IN ANOTHER SURGE OVERNIGHT TONIGHT WELL INTO THU. THE LONG 
DURATION GALE EVENT WILL RESULT IN A PLUME OF NE SWELL AT 8-11 
FT PROPAGATING TO THE S-SW AWAY FROM THE IMMEDIATE GULF OF 
TEHUANTEPEC.

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

THE MONSOON TROUGH EXTENDS FROM 07N78W TO 09N90W. THE ITCZ 
EXTENDS FROM 09N90W TO 07N100W TO 09N111W THEN RESUMES FROM 
09N120W TO 08N130W TO 09N140W. THERE IS NO SIGNIFICANT 
CONVECTION NOTED AT THIS TIME. 

...DISCUSSION... 

GULF OF CALIFORNIA...THE PRESSURE GRADIENT BETWEEN 1041 MB HIGH 
PRES OVER THE U.S. GREAT BASIN REGION AND TROUGHING OVER NW 
MAINLAND MEXICO IS PRODUCING FRESH WINDS OVER  THE GULF OF 
CALIFORNIA N OF 26N. THE HIGH PRESSURE AREA WILL WEAKEN 
SIGNIFICANTLY AND AS A RESULT WINDS WILL DIMINISH TO 20 KT OR 
LESS LATER THIS MORNING.

LOW PRESSURE EARLIER OVER THE N-CENTRAL PACIFIC HAS DISSIPATED 
WITH ONLY AN ASSOCIATED TROUGH EXTENDING OVER THE AREA FROM 
29N122W TO 20N130W. THE PRESSURE GRADIENT BETWEEN THE LOW AND 
1030 MB HIGH PRESSURE CENTERED N OF THE FORECAST WATERS NEAR 
44N130W HAS WEAKENED ENOUGH DURING THE PAST SEVERAL HOURS TO 
ALLOW FOR WINDS TO DIMINISH TO FRESH LEVELS. LINGERING 8-10 FT 
NORTHERLY SWELL COVERS THE AREA N OF 23N BETWEEN 127W AND 138W. 
THE TROUGH IS FORECAST TO DISSIPATE DURING THE NEXT 18 HOURS 
WITH ASSOCIATED WINDS AND SEAS DIMINISHING/SUBSIDING BY THEN.

WEAK SURFACE RIDGING POKING INTO THE WESTERN WATERS TO THE SW-W 
OF THE FRONT COMBINED WITH LOWER PRESSURES ALONG THE ITCZ IS 
SUPPORTING AN AREA OF FRESH TRADES OVER THE W CENTRAL WATERS. 
THESE WINDS COMBINED WITH LONGER PERIOD NW SWELL IS PRODUCING 
COMBINED SEAS OF 8-10 FT GENERALLY FROM 03N TO 20N W OF 132W. 
THESE SEAS WILL DECAY TO LESS THAN 8 FT BY 48 HOURS.

A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 13N116W TO 
08N115W. ASSOCIATED SCATTERED MODERATE CONVECTION IS WITHIN 180 
NM E OF THE TROUGH AXIS. THIS TROUGH IS FORECAST TO DISSIPATE AS 
IT MOVES WESTWARD AROUND 10 KT.

GULF OF PAPAGAYO...NOCTURNAL PULSING OF WINDS TO 20 KT CAN BE 
EXPECTED OVER THE NEXT COUPLE OF NIGHTS INTO THE EARLY MORNING 
HOURS...WITH THE POTENTIAL FOR STRONGER GAP FLOW BY FRI AS TRADE 
WIND FLOW INCREASES ACROSS THE WESTERN CARIBBEAN SEA AND HIGH 
PRESSURE BUILDS ACROSS CENTRAL AMERICA. 

$$
COBB