000
AXPZ20 KNHC 310355
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH AXIS FROM 07N77W TO 04N85W TO 06N97W. ITCZ AXIS 
FROM 06N97W TO 07N117W TO 08N134W TO BEYOND 06N140W. SCATTERED 
MODERATE TO STRONG WITHIN 60-90 NM EITHER SIDE OF THE AXIS 
BETWEEN 126W AND 135W. 

...DISCUSSION...
WEAKENING HIGH PRESSURE 1025 MB CENTERED NEAR 31N134W WITH RIDGE 
AXIS EXTENDING SE TO NEAR 20N112W. THE PRESSURE GRADIENT BETWEEN 
THIS FEATURE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ IS 
MAINTAINING FRESH TRADEWIND FLOW FROM 10N TO 20N W OF 130W. THE 
AREA OF HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SHIFT E 
THROUGH LATE SUN ALLOWING A COLD FRONT TO MOVE INTO THE NW PART 
OF THE AREA ON SUN. WITH HIGH PRESSURE WEAKENING AND RETREATING 
THE AREAL COVERAGE OF FRESH 20 KT TRADEWINDS WILL DECREASE IN 
COVERAGE SAT AND DIMINISH BELOW 20 KT BY EARLY SUN. S TO 
SW WINDS WILL INCREASE OVER THE FAR NW PART OF THE AREA AHEAD OF 
THE COLD FRONT SUN. SEAS ARE FORECAST TO BUILD RAPIDLY TO 14 FT 
BEHIND THE COLD FRONT BY SUN EVENING. 

GULF OF PAPAGAYO...
FRESH TRADEWINDS OF 20-25 KT FROM THE WESTERN CARIBBEAN CONTINUE 
TO FLOW THROUGH THE CENTRAL AMERICA GAPS INTO THE GULF OF 
PAPAGAYO. WINDS WILL PEAK DURING THE EARLY MORNING HOURS WITH 
THE ADDED COMPONENT OF NOCTURNALLY DRIVEN KATABATIC WINDS. THE 
AREA OF WINDS MAY EXPAND SOMEWHAT WESTWARD ON SAT AND CONTINUE 
INTO SUN. 

GULF OF TEHUANTEPEC...
BROAD TROUGHING IS SETTING UP OVER THE YUCATAN PENINSULA WITH 
HIGH PRESSURE PREVAILING OVER EASTERN MEXICO. THE PRESSURE 
GRADIENT BETWEEN THESE FEATURES...AND RESULTING LOCALLY 
INCREASED WINDS WILL FUNNEL THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC BY SAT MORNING WITH FRESH NORTHERLY WINDS OF 
20-25 KT IN PLACE OVER THE GULF OF TEHUANTEPEC BY LATE SAT. 
WINDS WILL INCREASE SUN AS STRONGER HIGH PRESSURE BUILDS 
SOUTHWARD ACROSS MEXICO AND REACH GALE FORCE SUN EVENING. GLOBAL 
MODELS SUGGEST THE POSSIBILITY OF STORM FORCE WINDS MON NIGHT 
INTO TUE. A GALE WARNING HAS BEEN ISSUED IN THE HIGH SEAS 
FORECAST. REFER TO AWIPS/WMO HEADERS MIAHSFEP2/FZPN03KNHC FOR
ADDITIONAL INFORMATION. 
     
$$
COBB