000
AXPZ20 KNHC 120356
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED DEC 12 2007

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 
0345 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 9N84W 10N112W 
7N125W 8N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
NOTED WITHIN 60 NM EITHER SIDE OF LINE 9N95W 11N101W 8N108W.
ASSOCIATED WITH A TROUGH EXTENDING FROM 8N112W TO 15N110W. THIS 
TROUGH IS EXPECTED TO MOVE W AT ABOUT 8 KT FOR THE NEXT FEW DAYS.
SCATTERED MODERATE CONVECTION IS ALSO NOTED IN CLUSTERS ALONG 
THE ITCZ BETWEEN 112W AND 134W.

...DISCUSSION...
AN UPPER LONGWAVE TROUGH LIES ALONG THE W COAST N AMERICA WITH 
ITS AXIS ALONG 112W INTO THE E PAC TO A BASE NEAR 11N112W. AN 
EMBEDDED CYCLONE IS AT 31N113W AND IS SHIFTING NE AND FILLING 
WITH TIME. SOME UPPER MOISTURE ACCOMPANIES THE CYCLONE OVER ITS 
NE QUADRANT. DRY UPPER AIR IS OBSERVED N OF 17N BETWEEN 120W AND 
107W.

CONVECTION CONTINUES TO FLARE ALONG THE TROUGH MENTIONED ABOVE 
WITH THE RESULTANT DEBRIS MOISTURE CONVERGING INTO A TROPICAL 
PLUME NOTED ROUGHLY WITHIN 270 NM EITHER SIDE OF LINE 9N106W 
21N103W TO BEYOND 31N96W.

JUST TO THE W OF THE UPPER LONGWAVE TROUGH...AN UPPER SHORTWAVE 
RIDGE LIES ALONG 135W AND ORIGINATES FROM AN UPPER ANTICYCLONE 
WELL TO S NEAR 17S118W. UPPER MOISTURE IS SPILLING ACROSS THE 
RIDGE OVER THE DISCUSSION AREA FROM 9N TO 27N W OF 125W. 

THE E PORTION OF THE DISCUSSION AREA IS DOMINATED BY A LONGWAVE 
RIDGE WITH ITS AXIS ALONG 11N74W 27N88W 45N98W. SOME DEBRIS 
MOISTURE FROM FORMER ITCZ CONVECTION NEAR THE PAC COAST OF  
PANAMA IS TRAPPED UNDER THE RIDGE AND IS SPREADING NE INTO THE 
SW CARIBBEAN. OTHERWISE THE UPPER LEVELS ARE DRY S OF 28N E
OF 93W.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS INTO THE AREA ALONG 
32N137W 22N106W.

GAP WINDS...CARIBBEAN WINDS EXPECTED TO SURGE THROUGH THE GULF 
OF PAPAGAYO TO NEAR 9N94W THROUGH ABOUT 18 HOURS THEN DIMINISH. 
NLY DRAINAGE SURGES IN THE 15 TO 20 KT RANGE ARE EXPECTED IN THE 
GULF OF TEHUANTEPEC JUST AFTER SUNRISE FOR THE NEXT FEW DAYS.  

$$
NELSON