000
AXPZ20 KNHC 280952
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI DEC 28 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 8N77W 7N90W 6N97W 
9N119W 7N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 15 NM 
OF 6.5N87.5W AND ALSO OBSERVED FROM 7N TO 11N BETWEEN 110W AND 
119W.

...DISCUSSION...
A LONGWAVE TROUGH DOMINATES CENTRAL N AMERICA WITH AN ASSOCIATED 
SHORT WAVE TROUGH EXTENDING SW INTO THE REGION ALONG 32N103W TO 
21N127W THEN S TO A BASE NEAR 1N119W. A BAND OF UPPER DRY AIR IS 
NOTED WITHIN ROUGHLY 240 NM EITHER SIDE OF LINE 30N100W 24N120W 
27N140W. A SHARP SHORTWAVE RIDGE HAS COLLAPSED E ALONG 32N148W 
32N120W AND IS ACCOMPANIED BY UPPER LEVEL MOISTURE N OF A WELL 
DEFINED LINE ALONG 30N BETWEEN 107W AND 150W. ANOTHER UPPER 
RIDGE EXTENDS E INTO THE AREA WITH ITS CREST ROUGHLY ALONG 
22N140W 12N122W. UPPER MOISTURE IS ADVECTED E UNDER THIS RIDGE 
WITH SOME MOISTURE CONTINUING CYCLONICALLY E IN RESPONSE TO THE 
UPPER TROUGH. 

A TROPICAL ANTICYCLONE OVER S AMERICA HAS A RIDGE EXTENDING NW 
ACROSS CENTRAL AMERICA TO A CREST ALONG 13N106W 27N100W 32N82W. 
CONVECTION ALONG THE ITCZ IS ENHANCED BETWEEN 104W AND 120W... 
WITH THE RESULTANT DEBRIS MOISTURE CONCENTRATING INTO A TROPICAL 
PLUME WITHIN 210 NM EITHER SIDE OF LINE 15N113W 25N95W 31N80W.
 
AT THE LOW LEVELS A SURFACE RIDGE EXTENDS ALONG 32N138W 12N102W
SUPPORTING 20-30 KT TRADE WINDS S OF THE RIDGE AXIS.

GAP WINDS TO ABOUT 20 KNOTS WILL CONTINUE FOR ANOTHER DAY OR SO 
THROUGH IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO. EXTENDED 
OUTLOOK...A MAJOR WIND EVENT IS SETTING UP FOR THE GULF OF 
TEHUANTEPEC GAP IN THE WAKE OF A STRONG COLD FRONT IN THE GULF 
OF MEXICO TUE EVENING.

NORTHWEST WINDS IN THE GULF OF CALIFORNIA WILL FLUCTUATE AROUND 
20 KT DURING THE NEXT 48 HOURS.

$$
NELSON