000
AXPZ20 KNHC 311503
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 31 2011

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 AXIS FROM 09N84W TO 04.5N92W. ITCZ AXIS FROM 
04.5N92W TO 07N120W TO BEYOND 08N140W. SCATTERED MODERATE TO 
STRONG CONVECTION WAS NOTED WITHIN 90 NM OF AXIS FROM 118W TO 
130W.

...DISCUSSION...
THE AREA OF HIGH PRESSURE THAT HAD BEEN CENTERED N OF THE AREA 
HAS WEAKENED SIGNIFICANTLY...WITH THE PRIMARY HIGH PRESSURE 
CENTERED FURTHER N NEAR 39N126W. WITH THIS AREA OF HIGH PRESSURE 
WEAKENING...THE AREA OF FRESH TRADEWINDS ARE NOW LIMITED TO THE 
AREA FROM 09N TO 18N W OF 135W. ANOTHER SMALL AREA OF FRESH 
TRADEWINDS PREVAILS FROM 06N TO 09W BETWEEN 118W AND 135W. CIMMS 
SATELLITE DERIVED CONVERGENCE IS INDICATING ENHANCED LOW LEVEL 
CONVERGENCE OVER THIS AREA DUE TO THESE FRESH TRADEWINDS. THIS 
CONVERGENCE...AND UPPER LEVEL DIVERGENCE EAST OF A SHARP UPPER 
LEVEL TROUGH WITH AXIS CENTERED ROUGHLY ALONG 140W IS STRONG 
ENOUGH TO MAINTAIN ACTIVE CONVECTION AS NOTED ABOVE. 

WITH THE AREA OF HIGH PRESSURE CONTINUING TO WEAKEN...TRADEWINDS 
WILL DIMINISH FURTHER BELOW 20 KT BY TONIGHT. THE ASSOCIATED 
HIGH PRESSURE RIDGE WILL SHIFT EASTWARD ENABLING A SURFACE COLD 
FRONT TO ENTER THE FAR NW PART OF THE AREA SUN. SW WINDS WILL 
FRESHEN OVER THE FAR NW PART OF THE AREA AHEAD OF THE COLD 
FRONT. THE COLD FRONT WILL RAPIDLY WEAKEN AND DISSIPATE BY 
MONDAY. HOWEVER...THE FRONT WILL USHER IN A SET OF LARGE LONG 
PERIOD NW SWELLS...WITH COMBINED SEAS AS HIGH AS 20 FT PEAKING 
MON MORNING. 

GULF OF PAPAGAYO...
FRESH TO STRONG TRADEWINDS OVER THE WESTERN CARIBBEAN CONTINUE 
TO FUNNEL THROUGH THE NICARAGUA MOUNTAINS INTO THE GULF OF 
PAPAGAYO. WINDS WILL PEAK DURING THE LATE NIGHT AND EARLY 
MORNING HOURS WITH THE ADDED COMPONENT OF NOCTURNALLY DRIVEN 
KATABATIC WINDS. 

GULF OF TEHUANTEPEC...
A WEAK TROUGH OVER THE YUCATAN PENINSULA JUST E OF THE BAY OF 
CAMPECHE COMBINED WITH HIGH PRESSURE OVER EASTERN MEXICO IS 
CREATING LOCALIZED NORTHERLY WINDS WHICH ARE FUNNELING THROUGH 
THE CHIVELA PASS RESULTING IN FRESH WINDS OVER THE GULF OF 
TEHUANTEPEC. WINDS FUNNELING THROUGH THE CHIVELA PASS WILL 
INCREASE SUN AHEAD OF A STRONG COLD FRONT SHIFTING ACROSS THE 
GULF OF MEXICO. WINDS WILL REACH GALE FORCE LATE SUN WITH SEAS 
BUILDING TO NEAR 15 FT BY MON MORNING.
     
GULF OF PANAMA...
FRESH TO STRONG NE WINDS OVER THE SW CARIBBEAN WILL FUNNEL INTO 
ACROSS PANAMA. THIS WILL MAINTAIN FRESH 20 KT WINDS OVER THE 
GULF OF PANAMA THROUGH AT LEAST MONDAY MORNING.

$$
AL