000
AXPZ20 KNHC 290341
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE DEC 29 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...05N77W TO 
07N90W TO 05N103W TO 08N123W TO 08N140W. NO DEEP CONVECTION. 

...DISCUSSION...

ALOFT...A STRONG SHORTWAVE TROUGH IS APPROACHING THE W COAST OF 
BAJA CALIFORNIA GENERATING MULTILAYER CLOUDS WITH EMBEDDED AREAS 
OF MAINLY LIGHT RAIN. THIS CLOUDINESS IS ALSO AFFECTING THE NW 
PORTION OF MAINLAND MEXICO. THE SHORTWAVE IS FORECAST TO MOVE 
EAST ACROSS NORTHERN MEXICO AND THE SW CONUS TODAY. A ZONAL 
FLOW PREVAILS ALONG MUCH OF THE REMAINDER OF THE FORECAST AREA. 
AN UPPER ANTICYCLONE CENTERED OVER THE CENTRAL CARIBBEAN SEA 
EXTENDS A RIDGE ACROSS CENTRAL AMERICA INTO THE EPAC MAINLY E 
OF 90W. PATCHES OF MIDDLE TO UPPER LEVEL MOISTURE ARE MOVING 
AROUND THE WESTERN PERIPHERY OF THIS ANTICYCLONE. 

A SURFACE RIDGE IS BUILDING ACROSS THE AREA. THE RIDGE IS 
ANCHORED ON A 1023 MB HIGH LOCATED NEAR 31N135W. A BROAD AREA OF 
FRESH TO STRONG TRADE WINDS IS NOTED N OF THE ITCZ TO 18N W OF 
125W. THESE CONDITIONS WILL PERSIST THROUGH AT LEAST WED AS THE 
HIGH PRES REMAINS JUST N OF THE LOCAL REGION.

GAP WINDS...
ACCORDING TO A RECENT WINDSAT PASS...NLY WINDS HAVE REACHED GALE 
FORCE OF 35 KT ACROSS THE GULF OF TEHUANTEPEC. THE PRESENCE OF A 
ROPE CLOUD IN LATEST VIS SATELLITE IMAGERY ALSO INDICATED THE 
LEADING EDGE OF THE COLD OUTFLOW ASSOCIATED WITH THIS GAP WIND 
EVENT. WINDS ARE EXPECTED TO DIMINISH TO BELOW GALE FORCE IN 
ABOUT 12 HOURS BUT WILL REMAIN IN THE 20 TO 30 KT RANGE THROUGH 
TONIGHT.  

NE TO E WINDS ARE FORECAST TO INCREASE TO 20 TO 25 KT ACROSS THE 
GULF OF PAPAGAYO TONIGHT AND SPREAD WWD AS FRESH TRADE WIND FLOW 
IN THE SW CARIBBEAN FUNNELS THROUGH THE GAP. THE WINDS ARE 
GREATEST DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE 
AID OF DRAINAGE FLOW. 

SEA CONDITIONS ARE DOMINATED BY LONG PERIOD NW SWELL (WAVE 
PERIODS OF UP TO 18 SECONDS) WITH SIGNIFICANT WAVE HEIGHTS AS 
HIGH AS 14 FT. THIS SWELL EVENT WILL CONTINUE TO SPREAD SE 
REACHING NEAR 100W THIS EVENING. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE
  
$$
GR