000
AXPZ20 KNHC 150328
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE DEC 15 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 ITCZ AXIS IS ALONG 05N77W TO 07N102W TO 08N120W TO 07N140W. 
SCATTERED MODERATE CONVECTION IS NEAR 07N102W AND WITHIN 100 NM 
N OF AXIS W OF 132W.  

...DISCUSSION...
ALOFT...A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE NORTHERN 
BAJA PENINSULA SW TO NEAR 15N125W. A JET STREAM BRANCH WITH CORE 
WINDS OF 70-90 KT ROUNDS THE BASE OF THE TROUGH TURNING NE 
ACROSS THE SOUTHERN BAJA CALIFORNIA PENINSULA AND NW MEXICO INTO 
CENTRAL TEXAS. TO THE W OF THE TROUGH...A RIDGE DOMINATES THE W 
PORTION OF THE AREA...PARTICULARLY N OF THE ITCZ AND W OF 130W.
MODERATE TO STRONG UPPER LEVEL SUBSIDENCE DOMINATES MUCH OF THE 
AREA E OF 110W INCLUDING SOUTH-CENTRAL MEXICO AND MOST OF 
CENTRAL AMERICA.  

AT THE SURFACE...A 1022 MB HIGH PRES IS CENTERED JUST N OF THE 
FORECAST REGION 31N122W. SHIP OBSERVATIONS...ASCAT DATA AND 
WINDSAT INDICATE A BROAD AREA OF FRESH TO STRONG TRADE WINDS ON 
THE SOUTHERN PERIPHERY OF THE SURFACE HIGH PRES...MAINLY FROM 
08N TO 20N W OF 115W. SHIP OBSERVATIONS ALSO INDICATE 20 KT 
WINDS BETWEEN THE HIGH PRES AND THE BAJA PENINSULA COAST. THIS 
FEATURE WILL STRENGTHEN...MAINTAINING THE FRESH TO STRONG TRADES 
THROUGH MIDWEEK. A COLD FRONT WILL ENTER THE FAR NW PORTION OF 
THE DISCUSSION AREA TONIGHT...EXTENDING FROM 30N136W TO 27N140W 
TUE EVENING THEN WILL DISSIPATE. A PAIR OF TROUGHS ARE NOTED 
EMBEDDED WITHIN THE ITCZ. THE FIRST ONE EXTENDS FROM 11N101W TO 
05N104W. SCATTERED SHOWERS ARE NEAR THE INTERSECTION OF THE 
TROUGH AXIS AND THE ITCZ. THE SECOND RUNS FROM 12N121W TO 
05N123W. SCATTERED SHOWERS ARE BEHIND THE TROUGH AXIS FROM THE 
ITCZ TO 10N.

SEA HEIGHTS ARE BEGINNING TO INCREASE ACROSS THE N WATERS AS A  
ANOTHER SET OF NW SWELL MOVES INTO THE DISCUSSION AREA. SEAS OF 
UP TO 16 FT ARE EXPECTED NW OF LINE FROM 30N125W TO 20N130W WED 
EVENING. 

SURFACE HIGH PRES WILL ALSO BUILD OVER THE GREAT BASIN PRODUCING 
A TIGHT PRES GRADIENT. AS A RESULT...WINDS WILL INCREASE ACROSS 
THE GULF OF CALIFORNIA STARTING TONIGHT...AND ARE EXPECTED TO 
PEAK IN ABOUT 24 HOURS REACHING 20 TO 25 KT.  

GAP WINDS...
AN EARLIER ASCAT PASS INDICATED FRESH TO STRONG GAP WIND FLOW 
PERSISTING THROUGH THE GULF OF TEHUANTEPEC. MARINE GUIDANCE 
SUGGESTS THAT THIS WIND EVENT WILL CONTINUE AND THEN BECOME 
STRONGER WED INTO THU AS A COLD FRONT PUSHES INTO THE SW GULF 
WED. 

NE TO E WINDS OF 20 TO 25 KT ARE STILL BLOWING ACROSS THE 
GULF OF PAPAGAYO AS A TIGHT PRES GRADIENT ACROSS THE WESTERN 
CARIBBEAN IS ALLOWING ELY TRADE WINDS TO FUNNEL ACROSS COSTA 
RICA AND NICARAGUA INTO THE EASTERN PACIFIC. THESE WINDS ARE 
EXPECTED TO SLIGHTLY DIMINISH DURING THE NEXT 24 TO 48 HOURS. 


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