000
AXPZ20 KNHC 201539
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT NOV 20 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N86W TO 
13N115W TO 09N123W TO 09N140W. SCATTERED MODERATE ISOLATED 
STRONG WITHIN 180 NM N OF AXIS BETWEEN 103W AND 111W. SCATTERED 
MODERATE WITHIN 65 NM OF LINE 14.5N92W TO 10N93W.

...DISCUSSION...
AMPLIFIED PATTERN IN PLACE OVER THE DISCUSSION AREA WITH A DEEP 
LAYERED TROUGH EXTENDING FROM A CYCLONIC CIRCULATION OFF THE 
WASHINGTON COAST SWD TO 28N132W. THIS TROUGH WAS PROVIDING 
SUPPORT FOR A COLD FRONT WHICH EXTENDED FROM 30N125W TO 27N140W.
THIS FRONT WAS USHERING IN N TO NE WINDS OF 20 KT WITH SEAS 
BUILDING 8 TO 12 FT IN NW SWELL. A REINFORCING SHORTWAVE TROUGH 
IS FORECAST BY THE GLOBAL MODELS TO DIVE DOWN INTO THE FAR NW 
PORTION OF THE DISCUSSION AREA AND COMBINED WITH AN UPSTREAM 
AMPLIFIED RIDGE WILL ALLOW AN EXPANDING AREA OF HIGH PRESSURE TO 
BUILD INTO THE AREA WITH NE WINDS OF 20 KT DEVELOPING FROM 12N 
TO 23N W OF 120W AND A SECOND SURGE OF NW SWELL OF 9 TO 14 FT 
TO SPREAD SWD INTO THE AREA N OF 23N W OF 120W BY TUE. 

ELSEWHERE OVER THE AREA A BROAD SWATH OF MODERATE TO STRONG SW 
WINDS ALOFT EXTEND FROM THE TROPICS W OF 130W NE ACROSS THE NE 
PACIFIC/BAJA CALIFORNIA INTO NW MEXICO. THE WINDS WERE ADVECTING 
SOME MID TO UPPER LEVEL MOISTURE NE TOWARD A DEVELOPING STORM 
SYSTEM OVER THE INTERMOUNTAIN WEST. THIS AREA OF WINDS CAPPED A 
BROAD AREA OF SUBSIDENCE COVERING THE BASIN FROM THE EQUATOR TO 
22N E OF 120W. A SURFACE TROUGH EXTENDING FROM 17N114W TO 
09N122W WAS SITUATED IN THIS AREA. SCATTERED MODERATE CONVECTION 
WITHIN 90 NM W OF THE TROUGH WAS STRUGGLING IN THIS DRY 
ENVIRONMENT.   

GAP WINDS...
OBSERVATIONS FROM SALINA CRUZ INDICATED N WINDS OF 20 TO 30 KT 
WITH RECENT GUSTS TO 35 KT AS OF 15 UTC. STILL AWAITING  
CONFIRMATION OF A HIGH RESOLUTION ASCAT PASS TO DETERMINE 
WHETHER THE GALE IN THE GULF OF TEHUANTEPEC HAS ENDED. IN ANY 
EVENT WINDS ARE FORECAST TO GRADUALLY WEAKEN OVER THE NEXT 48 
HOURS TO LESS THAN 20 KT BY LATE TUE. 

FRESH TO STRONG WINDS OVER THE WESTERN CARIBBEAN HAVE BEGUN TO 
FUNNEL THROUGH THE CENTRAL AMERICA PASSES...BRINGING FRESH WINDS 
INTO THE GULF OF PAPAGAYO. THESE WINDS WILL PULSE WITH THE 
STRONGEST WINDS DURING THE OVERNIGHT AND EARLY MORNING HOURS 
WITH THE AID OF NOCTURNAL DRAINAGE FLOW OFF THE MOUNTAINOUS 
TERRAIN. 

$$
COBB