000
AXPZ20 KNHC 250922
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1005 UTC WED DEC 25 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 
0900 UTC.

...SPECIAL FEATURE...

THE 0356W ASCAT PASS SHOWED NORTHERLY WINDS OF 30 TO 40 KT 
FUNNELING INTO THE GULF OF TEHUANTEPEC. GALES WILL CONTINUE 
THROUGH THIS MORNING ENDING AROUND 1800 UTC WHEN THE FORECAST 
CALLS FOR NORTHERLY WINDS OF 20 TO 30 KT. SEAS ARE EXPECTED TO 
SUBSIDE TO 12-15 FT THIS MORNING...AND TO 8-10 FT TONIGHT. FRESH 
TO STRONG WINDS WILL EXTEND WESTWARD TO NEAR 110W WITH SEAS TO 9 
FT TODAY. WINDS OF 20-30 KT ARE FORECAST TO PERSIST ACROSS THE 
AREA THROUGH THE REST OF THE FORECAST PERIOD WITH SEAS OF 8-10 
FT. DURING THE UPCOMING WEEKEND...MARINE GUIDANCE SUGGESTS THE 
PRESENCE OF MINIMAL GALE FORCE WINDS ACROSS THE GULF OF 
TEHUANTEPEC...PARTICULARLY DURING THE OVERNIGHT AND EARLY MORNING 
HOURS WITH THE AID OF THE NOCTURNAL DRAINAGE FLOW.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

MONSOON TROUGH EXTENDS FROM 05N77W TO 08N84W TO 07N87W. ITCZ 
CONTINUES FROM 07N87W TO 06N100W TO 07N120W TO 09N140W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 
10N TO 15N W OF 134W. 

...DISCUSSION... 

WEAKENING RIDGE OF HIGH PRESSURE EXTENDS SE FROM 35N130W TO 
20N112W. THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES 
ASSOCIATED WITH THE ITCZ IS PRODUCING AN AREA OF ENHANCED TRADES 
W OF 120W. STRONG DIVERGENCE E OF AN UPPER TROUGH IS PRODUCING A 
LARGE AREA OF MID/UPPER LEVEL CLOUDINESS WITH EMBEDDED SHOWERS 
AND ISOLATED TSTMS FROM 10N TO 15N W OF 134W. MOST OF THIS 
CONVECTIVE ACTIVITY IS ASSOCIATED WITH A SURFACE TROUGH THAT 
EXTENDS FROM 16N135W TO 10N136W. SCATTEROMETER DATA SHOWS FRESH 
TO STRONG WINDS W OF THE TROUGH AXIS THAT SHOULD SHIFT WESTWARD 
INTO THE CENTRAL PACIFIC THROUGH THU. NW WINDS OF 15-20 KT ARE 
NOTED PER SCATTEROMETER DATA ACROSS THE GULF OF CALIFORNIA. 
ANOTHER UPPER LEVEL TROUGH IS HELPING TO INDUCE AN AREA OF  
SCATTERED SHOWERS AND TSTMS FROM 14N TO 17N BETWEEN 104W AND 
108W.

LONG PERIOD NW SWELLS ARE SPREADING SOUTHEASTWARD TOWARD THE 
COAST OF COLOMBIA AND ECUADOR. THIS SWELL IS MIXING WITH NE SEAS 
GENERATED DOWNSTREAM OF THE GULF OF TEHUANTEPEC...CREATING A 
LARGE AREA OF 8-12 FT SEAS FROM 05N TO 14N BETWEEN 93W AND 110W. 
ANOTHER SET OF LONG PERIOD NW SWELLS WILL REACH THE NW PORTION 
OF THE FORECAST REGION TODAY AND SPREAD SOUTHEASTWARD AFFECTING 
MOST OF THE WATERS W OF 110W BY FRI. EXPECT BUILDING SEAS TO 8 
FT ACROSS THE NW WATERS TONIGHT AND THU IN ASSOCIATION WITH THIS 
NEW SWELL EVENT.

WINDS WILL CONTINUE TO PULSE TO 20-25 KT EARLY THIS MORNING  
THROUGH THE GULF OF PAPAGAYO. SEAS WILL BUILD TO NEAR 8 FT. 
 
$$
GR