000
AXPZ20 KNHC 111539
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE DEC 11 2012

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.

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

THE MONSOON TROUGH IS ALONG FROM 08N78W TO 08N90W TO LOW PRES 
NEAR 10N103W 1009 MB. THE INTERTROPICAL CONVERGENCE ZONE AXIS 
CONTINUES FROM THE LOW TO 10N120W TO 08N140W. SCATTERED MODERATE 
AND ISOLATED STRONG CONVECTION IS N OF 05N E OF 84W. SCATTERED 
MODERATE CONVECTION IS WITHIN 180 NM N OF THE ITCZ W OF 123W. 
SIMILAR CONVECTION IS WITHIN 30 NM EITHER SIDE OF A LINE FROM 
11N116W TO 12N127W.

...DISCUSSION...

DEEP LAYERED RIDGING EXTENDS FROM 27N126W TO A PARENT 
ANTICYCLONE ALOFT NEAR 33N143W COINCIDENT WITH 1038 MB SURFACE 
HIGH PRES NEAR 38N148W. A TIGHT PRES GRADIENT EXISTS S OF THE 
RIDGE WITH FRESH TO STRONG NE WINDS FROM 14N TO 20N W OF 133W 
ALONG WITH SEAS TO 10 FT. A SURROUNDING AREA OF 8 TO 9 FT MIXED 
NE AND NW SWELL COVERS THE WATERS N OF 12N W OF A LINE FROM 
30N125W TO 12N130W. THIS PATTERN WILL NOT CHANGE MUCH DURING THE 
NEXT FEW DAYS WITH THE EXCEPTION OF A COLD FRONT THAT WILL 
WEAKEN WHILE DROPPING S OF 30N WED MORNING...DISSIPATING OVER W 
PORTIONS BY THU MORNING.

A MID TO UPPER TROUGH IS DIGGING SOUTHWARD WHILE EXTENDING FROM 
THE WESTERN TEXAS/MEXICO BORDER NEAR 30N105W TO ACROSS THE 
CENTRAL BAJA CALIFORNIA PENINSULA THEN NW TO 30N123W. VERY DRY 
AIR IS PRESENT BEHIND THIS TROUGH AS INDICATED BY WATER VAPOR 
SATELLITE IMAGERY. FRESH TO STRONG NW WINDS ARE PRESENT AT THE 
SURFACE IN THE GULF OF CALIFORNIA N OF 25N BETWEEN HIGH PRES 
OVER THE U.S. GREAT BASIN REGION AND TROUGHING OVER WESTERN 
MEXICO. THESE WINDS ARE FORECAST TO DIMINISH TO 20 KT OR LESS 
TONIGHT AS THE PRESSURE GRADIENT IN THE REGION WEAKENS.

BROAD AND EXPANSIVE WESTERLY WINDS ALOFT COVER THE WATERS FROM 
10N TO 22N WITH TROPICAL MOISTURE FEEDING UP SW OF THE AREA TO 
ACROSS CENTRAL MEXICO TO THE WESTERN GULF OF MEXICO. A MID TO 
UPPER TROUGH IS TO THE E REACHING FROM GUATEMALA TO JUST W OF 
THE GALAPAGOS ISLANDS. MAINLY DRY AIR COVERS THE WATERS S OF 10N 
AND ALSO N OF THE EQUATOR E OF 100W.

CROSS-EQUATORIAL SE SWELL OF 8 TO 9 FT WITH PEAK WAVE PERIODS OF 
15 TO 17 SECONDS IS OVER THE FAR SW CORNER OF THE DISCUSSION 
AREA S OF 06N W OF 122W COMMINGLING WITH SHORTER PERIOD NW SEAS. 
THE HIGHER SEAS WILL PERSIST THROUGH THE NEXT 48 HOURS WHILE 
GRADUALLY DECAYING TO 8 FT BY THU MORNING.

GAP WINDS...
TRANQUIL CONDITIONS CURRENTLY EXIST IN THE GULF OF TEHUANTEPEC 
ALTHOUGH THIS WILL NOT LAST LONG. A COLD FRONT IS IN THE PROCESS 
OF MOVING THROUGH THE WESTERN GULF OF MEXICO. THIS FRONT WILL 
TEMPORARILY STALL THROUGH THIS AFTERNOON WITH A REINFORCING 
NORTHERLY PUSH KICKING IT TO THE E AND SE BY TONIGHT. NORTHERLY 
FLOW WILL THEN FEED THROUGH THE CHIVELA PASS TO THE GULF OF 
TEHUANTEPEC WITH FRESH TO STRONG NORTHERLY WINDS EXPECTED BY 
EARLY WED MORNING...QUICKLY INCREASING TO MINIMAL GALE FORCE BY 
WED EVENING. THE GALE CONDITIONS WILL THEN PERSIST THROUGH AT 
LEAST EARLY THU MORNING.

LIGHT WESTERLY WINDS AT THE SURFACE ARE CURRENTLY IN AND 
DOWNWIND OF THE GULF OF PAPAGAYO. THIS WILL CHANGE TONIGHT AS 
FRESH TO STRONG EASTERLY TRADES IN THE CARIBBEAN SEA SPREAD 
WESTWARD TOWARDS CENTRAL AMERICA...WITH SIMILAR WINDS SEEPING 
INTO THE GULF OF PAPAGAYO LATE WED NIGHT INTO EARLY THU MORNING.

$$
LEWITSKY