000
AXPZ20 KNHC 291500
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 29 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 5N77W 9N115W 8N100W 
6N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 200 
NM N OF AXIS FROM 115W-117W AND WITHIN 60 NM N OF AXIS FROM
130W-137W.

...DISCUSSION...
MID/UPPER LEVEL TROUGH EXTENDS FROM THE SOUTHERN ROCKIES ACROSS
NW MEXICO THROUGH CENTRAL BAJA CALIFORNIA TO AN ELONGATED UPPER
LEVEL CYCLONIC CIRCULATION NEAR 21N129W. A 90 KT JETSTREAM IS
S OF THE TROUGH AXIS FROM 16N140W TO 23N115W AND INTO WESTERN
MEXICO NEAR 23N103W. MODERATE TO STRONG SUBSIDENCE WITH DRY AIR
AT THE MID AND UPPER LEVELS OF THE ATMOSPHERE IS WITHIN 300 NM
N OF THE AXIS W OF 120W. AN UPPER LEVEL RIDGE IS NW OF THE TROUGH
AXIS. BROAD UPPER LEVEL RIDGE IN THE TROPICS IS S OF 20N BETWEEN
95W AND 120W...SOME UPPER LEVEL DIFFLUENCE IN THE WESTERN PORTION
OF THE RIDGE IS ENHANCING CONVECTIVE ACTIVITY ALONG THE ITCZ.

A WEAK UPPER LEVEL TROUGH SEPARATES THE PACIFIC RIDGE FROM A
LARGE MID/UPPER LEVEL ANTICYCLONE OVER THE WESTERN CARIBBEAN
NEAR JAMAICA. STRONG SUBSIDENCE COVERS THE AREA W OF 105W WHICH
IS SUPPRESSING CONVECTIVE ACTIVITY ALONG THE ITCZ.

SURFACE TROUGH IS ANALYZED ALONG THE ITCZ FROM 13N116W TO 7N116W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 60 NM
EITHER SIDE OF THE TROUGH FROM 8N TO 12N. ELSEWHERE STRONG
RIDGE COVERS THE AREA N OF 15N W OF 115W. THE RIDGES IS PRODUCING
STRONG ELY TRADE WINDS W OF 120W.

$$
DGS