000
AXPZ20 KNHC 140329
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON DEC 14 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 07N110W TO 06N125W TO 07N140W. SCATTERED MODERATE TO 
ISOLATED STRONG NEAR 08N130W AND FROM 06N TO 08N W OF 135W.

...DISCUSSION...

A SHORTWAVE TROUGH IS OVER THE NW PORTION OF THE AREA MOVING 
EAST AT AROUND 25 KT AND WILL STRENGTHEN AS IT APPROACHES MEXICO 
MONDAY. OTHERWISE NEARLY ZONAL FLOW COVERS THE AREA N OF 20N. A 
JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT ROUNDS THE BASE OF 
THE SHORTWAVE TROUGH ENTERING THE DISCUSSION AREA NEAR 22N140W.  
SOME MID/UPPER LEVEL MOISTURE IS NOTED ON WATER VAPOR IMAGERY N 
OF 22N WHILE MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR 
AT THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE DOMINATES THE 
AREA N OF THE ITCZ W OF 105W.

AN UPPER ANTICYCLONE LOCATED OVER THE NW CARIBBEAN EXTENDS A  
RIDGE ACROSS SE MEXICO AND MOST OF CENTRAL AMERICA INTO THE EPAC 
WHERE IS PRODUCING MODERATE TO STRONG SUBSIDENCE MAINLY E OF 
100W. THE SUBSIDENCE IS LIMITING CONVECTION ALONG THE ITCZ. 

A FRONTAL TROUGH IS MOVING ACROSS THE N WATERS EXTENDING FROM N 
BAJA CALIFORNIA TO NEAR 25N126W. W OF THE TROUGH...A 1020 MB 
HIGH PRES IS CENTERED NEAR 30N131W. FRESH TO STRONG TRADE WINDS 
ON THE SOUTHERN PERIPHERY OF THIS HIGH ARE EVIDENT PER AN 
EARLIER ASCAT PASS. THIS WEATHER PATTERN WILL PERSIST OVER THE 
NEXT COUPLE OF DAYS AS THE HIGH MOVES EWD. THE NEXT COLD FRONT 
IS EXPECTED TO REACH THE FAR NW PORTION OF THE FORECAST REGION 
IN ABOUT 48 HOURS. SW WINDS OF 20 KT WILL PRECEDE THE FRONT. 

MARINE GUIDANCE ALSO INDICATES AN INCREASE IN WINDS ACROSS THE 
GULF OF CALIFORNIA BEGINNING MON EVENING DUE TO THE PRESENCE OF 
A 1033 MB HIGH PRES OVER THE SW CONUS.  

A COUPLE OF TROUGH ARE ANALYZED ALONG THE ITCZ. THE FIRST TROUGH 
IS FROM 12N115W TO 05N116W. A SECOND TROUGH RUNS FROM 11N136W TO 
05N138W. MODERATE CONVECTION LOCATED EITHER SIDE OF THIS TROUGH 
AXIS IS MAINLY ASSOCIATED WITH THE ITCZ. 

LARGE AND LONG PERIOD NW SWELL CONTINUES TO SPREAD ACROSS THE 
REGION BEYOND THE EQUATOR. A NEW BATCH OF NW SWELL WITH WAVE 
PERIODS BETWEEN 14 TO 15 SECONDS IS NOW ENTERING THE N WATERS 
RAISING SEAS UP TO 12 FT. 

WINDS IN THE GULF OF PAPAGAYO ARE EXPECTED TO OSCILLATE BETWEEN 
20 TO 25 KT OVER THE NEXT 48 HOURS 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.

NLY WINDS OF 20 KT ARE STILL BLOWING ACROSS THE GULF OF 
TEHUANTEPEC. THE WINDS SHOULD DECREASE BY 36 HOURS...BUT ARE 
EXPECTED TO INCREASE AGAIN ABOUT MID WEEK.
  
$$
GR