000
AXPZ20 KNHC 292202
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 29 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

MONSOON TROUGH AXIS ANALYZED FROM SW CARIBBEAN ACROSS CENTRAL 
AMERICA ENTERING EPAC NEAR 09N84W TO 06N95W WHERE IT TRANSITIONS 
TO ITCZ...CONTINUING TO 05N107W TO 08N127W TO BEYOND 06N140W. NO 
SIGNIFICANT CONVECTION NOTED NEAR AXIS. 

...DISCUSSION...

AT UPPER LEVELS...ZONAL FLOW ALOFT HAS RECENTLY PREVAILED N OF 
THE AREA...N OF 30-35N...WITH A MIDDLE TO UPPER LEVEL TUTT LIKE 
AXIS MEANDERING FROM THE NRN GULF OF MEXICO WWD ALONG 30N TO 
NEAR 29N134W...THEN WEAKLY CONNECTING TO CUT OFF DEEP LAYERED 
LOW MENTIONED BELOW...CENTERED NEAR 14N143W. UPPER RIDGING 
CONTINUES TO THE E OF THIS UPPER LOW...WHILE STRONG WLY FLOW TO 
THE SOUTH OF THE UPPER LOW ARE CONTRIBUTING TO STRONG DIVERGENCE 
ALOFT ACROSS THE SE QUADRANT OF THE UPPER LOW. ASSOCIATED 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED IN 
SATELLITE IMAGERY FROM 12N TO 20N BETWEEN 129W AND 139W.   

AT LOWER LEVELS...
GULF OF TEHUANTEPEC...THE LONG-LASTING GAP WIND EVENT FINALLY 
CAME TO A CLOSE THIS MORNING...AS N WINDS DROPPED BELOW 20 KT.  
THIS WILL BE A SHORT RESPITE...HOWEVER...AS SOME ENHANCED 
PRESSURE GRADIENT ACROSS FROM THE GULF OF MEXICO TO THE GULF OF 
TEHUANTEPEC WILL BEGIN A NEW EVENT SATURDAY MORNING.  A RATHER 
VIGOROUS GULF OF MEXICO COLD FRONT WILL LIKELY BOOST THE GAP 
WINDS TO GALE FORCE BY SUNDAY NIGHT.  THE DURATION OF GALES MAY 
BE LENGTHY...POSSIBLY FROM SUNDAY NIGHT THROUGH WEDNESDAY. 

GULF OF PAPAGAYO...GAP WINDS CONTINUE TO FUNNEL ACROSS NICARAGUA 
AS FRESH TRADEWINDS PERSIST ACROSS MUCH OF THE CARIBBEAN. THESE 
GAP WINDS SHOULD PEAK EACH OF THE NEXT FEW DAYS IN THE LATE 
NIGHT AND EARLY MORNING HOURS AT AROUND 25 KT AND 8 FT SEAS.  
THESE CONDITIONS APPEAR LIKELY TO PERSIST FOR THE NEXT SEVERAL 
DAYS.

GULF OF CALIFORNIA...AS TYPICAL...THERE WERE NO OVER WATER 
OBSERVATIONS THROUGHOUT THE GULF WATERS TO CONFIRM COMPUTER 
MODEL FORECASTS...BUT GLOBAL MODELS INDICATE WINDS HAVE 
DIMINISHED TO LESS THAN 20 KT THROUGH THE BASIN...AND REMAIN SO 
THROUGH EARLY SUN...WHEN THE REGIONAL GRADIENT WILL INCREASE IN 
ASSOCIATION WITH A GULF OF MEXICO COLD FRONT.

A SURFACE TROUGH IS ANALYZED ALONG 138W FROM 11N TO 18N... 
ASSOCIATED WITH PERSISTENT CONVECTION OCCURRING ACROSS THE ERN 
SEMICIRCLE OF THE CUT OFF LOW MENTIONED ABOVE. THE COMBINATION 
OF THE TROUGH AND A 1030 MB HIGH NEAR 31N138W IS CAUSING A 
RATHER BROAD ZONE OF 20-25 KT TRADEWINDS BETWEEN 10N AND 25N W 
OF 130W. PEAK TRADEWINDS ACROSS THIS ZONE ARE AROUND 25 KT AND 
PEAK SIGNIFICANT WAVE HEIGHTS NEAR 12 FT. THE TROUGH SHOULD 
ADVECT WESTWARD SLOWLY AND WEAKEN AS THE UPPER LOW OPENS UP AND 
LIFTS OUT OVER THE NEXT TWO DAYS.

NO SIGNIFICANT WAVE HEIGHTS ABOVE 12 FT ARE CURRENTLY IN THE 
AREA OF RESPONSIBILITY.  THE NEXT LONG-PERIOD LARGE SWELL EVENT 
SHOULD REACH THE NW BORDER OF OUR AREA BEGINNING MONDAY.  SEAS 
OVER 12 FT ARE ALSO POSSIBLE BEGINNING MONDAY IN THE GULF OF 
TEHUANTEPEC.

$$
STRIPLING