000
AXPZ20 KNHC 161522 RRB
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 16 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...

MONSOON TROUGH FROM 09N83W TO 06N95W...WHERE IT TRANSITIONS TO 
ITCZ..CONTINUING TO 08N121W TO 07N126W TO 09N131W TO BEYOND 
07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
WITHIN 90 NM S OF AXIS BETWEEN 106W AND 118W.

...DISCUSSION...
A 1018 MB HIGH PRESSURE IS CENTERED NEAR 27N119W. A 1005 MB LOW 
PRESSURE CENTER IS LOCATED N OF THE AREA NEAR 34N130W. THE 
ASSOCIATED COLD FRONT ENTERS THE FORECAST REGION NEAR 30N127W 
THEN CONTINUES S AND SW TO 25N135W. THE PRESSURE GRADIENT 
BETWEEN THE FEATURES IS MAINTAINING FRESH TO STRONG SW WINDS E 
OF THE COLD FRONT N OF 27N. THE LOW PRESSURE CENTER HAS STARTED 
TO TO LIFT OUT TO THE NE. THIS WILL DRAG THE ASSOCIATED COLD 
FRONT EASTWARD OVER THE NEXT DAY...BUT ALSO LEAD TO THE COLD 
FRONT DISSIPATING BY SUN MORNING. HIGH PRESSURE WILL THEN BUILD 
BACK ACROSS THE N PART OF THE AREA SUN. WITH ONLY WEAK HIGH 
PRESSURE OVER THE NE PART OF THE AREA AT THIS TIME...TRADEWINDS 
REMAIN BELOW 20 KT. AS HIGH PRESSURE STARTS TO BUILD BACK ACROSS 
THE AREA ON SUN...TRADES WILL FRESHEN ONCE AGAIN BY SUN INTO 
EARLY NEXT WEEK.  

LONG PERIOD NW SWELL ASSOCIATED WITH THE LOW PRESSURE SYSTEM IS 
PUSHING ACROSS THE NW PART OF THE REGION WITH COMBINED SEAS TO 
10 FT. THIS SET OF NW SWELLS WILL PROPAGATE S AND E ACROSS THE 
REGIONAL WATERS OVER THE NEXT COUPLE OF DAYS WITH SEAS SUBSIDING 
TO 8-9 FT. A NEW SET OF NW SWELLS WILL ENTER THE NW PART OF THE 
AREA WITH COMBINED SEAS REACHING 11 FT BY SUN MORNING. 

GAP WINDS...
A GALE WARNING CONTINUES ACROSS THE GULF OF TEHUANTEPEC. LATEST 
HIGH RESOLUTION ASCAT PASS REPORTED WINDS OF 30 KT OVER THIS 
AREA. WITH A 5 KT LOW BIAS...IT IS LIKELY THAT GALE FORCE WINDS 
ARE OCCURRING OVER THE AREA AND SUPPORTS THE CONTINUANCE OF THE 
GALE WARNING. WINDS WILL DIMINISH TO JUST BELOW GALE FORCE 
DURING THE AFTERNOON HOURS TODAY AND SAT. HOWEVER...DURING THE 
OVERNIGHT AND EARLY MORNING HOURS...THE ADDED COMPONENT OF 
NOCTURNAL DRAINAGE FLOW WILL PUSH WINDS BACK ABOVE GALE FORCE IN 
THE GULF OF TEHUANTEPEC. SO...WILL CONTINUE WITH THE GALE 
WARNING THROUGH SUN MORNING TO ACCOUNT FOR THIS PULSING OF WINDS 
TO GALE FORCE. 
 
$$
AL