000
AXPZ20 KNHC 090331
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED DEC 09 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 07N95W TO 09N115W...THEN RESUMES 
FROM 11N120W TO 06N140W. SCATTERED MODERATE CONVECTION IS FROM 06N 
TO 10N BETWEEN 116W AND 128W. SIMILAR CONVECTION IS NEAR 15N117W.

...DISCUSSION...
ALOFT...A TROUGH/RIDGE PATTERN DOMINATES THE FORECAST REGION. THE 
TROUGH COVERS THE AREA N OF 12N W OF 130W. THE ASSOCIATED COLD 
FRONT EXTENDS FROM 30N137W TO 25N140W. S TO SW WINDS OF 20 TO 25 KT 
ARE NOTED WITHIN 180 NM AHEAD OF THE FRONT WITH NW WINDS OF 15 KT 
BEHIND THE FRONTAL SYSTEM. THE FRONT WILL TRACK ACROSS THE FAR 
NORTHERN WATERS REACHING FROM 30N129W TO 25N135W TO 20N138W WED 
EVENING WHERE IT WILL BEGIN TO DISSIPATE AS IT ENCOUNTERS SURFACE 
HIGH PRES W OF THE BAJA CALIFORNIA PENINSULA. LARGE AND LONG PERIOD 
NW SWELL WILL FOLLOW THE FRONT AND GRADUALLY INVADE THE DISCUSSION 
AREA REACHING THE EQUATOR AND BEYOND IN ABOUT 24 TO 36 HOURS. E OF 
THE TROUGH... THERE IS A BROAD UPPER-LEVEL RIDGE ANCHORED ON A HIGH 
LOCATED OVER SE MEXICO NEAR 16N97W. STRONG UPPER-LEVEL SUBSIDENCE 
AND IMPLIED DRY AIR MASS IS NOTED WITHIN THE RIDGE AXIS PARTICULARLY 
S OF 16N AND E OF 115W. SLY WINDS BETWEEN THE AFOREMENTIONED 
UPPER-LEVEL SYSTEMS ARE ADVECTING ABUNDANT MID TO UPPER LEVEL 
MOISTURE FROM THE ITCZ TO THE N AND NE AROUND THE NW PORTION OF THE 
ANTICYCLONE. AT THE SAME TIME...THE RIDGE IS ENHANCING CONVECTION 
ALONG THE ITCZ BETWEEN  115W AND 130W. 

WINDS HAVE DIMINISHED TO BELOW 20 KT N OF 25N E OF 120W TO THE COAST 
OF THE BAJA CALIFORNIA PENINSULA. A FEW SHIP REPORTS FROM 0000 UTC 
INDICATED N TO NE WINDS IN THE 10 TO 15 KT RANGE. NW SWELL OF 8 TO 
11 FT CONTINUES TO PROPAGATE INTO THE AREA. A 1021 MB HIGH CENTERED 
NEAR 30N122W DOMINATES THE REGIONAL WATERS N OF 20N E OF 130W. 

A 1011 MB LOW PRESSURE SYSTEM IS EMBEDDED WITHIN THE ITCZ... 
POSITIONED NEAR 13.5N116.5W...ALONG A SURFACE TROUGH EXTENDING FROM 
16N115W TO 10N117W. AN EARLIER ASCAT PASS SHOWED NE WINDS OF 20 KT 
JUST W OF THE TROUGH AXIS AND N OF THE LOW CENTER. AN AREA OF TRADE 
WINDS OF 20 KT IS NOTED AHEAD OF THE TROUGH AXIS MAINLY FROM 12N TO 
16N BETWEEN 115W AND 130W. 

GAP WINDS...
GULF OF PAPAGAYO...EASTERLY TRADES IN THE W CARIBBEAN WILL CONTINUE 
TO PASS OVER NICARAGUA AND COSTA RICA LEADING TO NE-E WINDS TO 20 KT 
IN THE GULF OF PAPAGAYO AND DOWNSTREAM TO 89W THROUGH WED 
AFTERNOON.  THE WINDS WILL BE STRONGEST DURING THE MORNING HOURS 
WITH THE AID OF DRAINAGE FLOW OFF THE LANDMASS.

$$
GR