000
AXPZ20 KNHC 181532
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JAN 18 2008

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...
ITCZ AXIS IS CENTERED ALONG 8N78W 6N90W 8N125W 6N140W. NO 
SIGNIFICANT CONVECTION.

...DISCUSSION...
NAGATIVELY TILTED UPPER LEVEL TROUGH EXTENDS FROM 32N138W SE TO
23N129W...DOWN STREAM RIDGE HAS AXIS FROM 32N131W TO 23N125W.
S OF THESE FEATURES IS MAILY ZONAL WLY FLOW...WITH A 95-105 KT
SUBTROPICAL JETSTREAM FROM 14N140W-14N120W...WHERE WINDS 
DECREASE TO 75-95 KT TO 13N107W. SCATTERED TO BROKEN HIGH LEVEL 
CIRRUS CLOUDS BEING ADVECTED EWD BY THE JET FROM 11N-20N W OF 
105W. A LARGE LONGWAVE TROUGH REMAINS ACROSS MUCH OF N AMERICA E 
OF THE ROCKIES. A SHARP MID/UPPER LEVEL SHORTWAVE IS APPROACHING 
THE BASE OF THE TROUGH AND CURRENTLY EXTENDS FROM SW TEXAS SW 
ACROSS NW MEXICO AND THE SOUTHERN TIP OF THE BAJA PENINSULA. AN 
UPPER LEVEL RIDGE EXTENDS FROM AN ANTICYCLONIC CIRCULATION OVER 
COLOMBIA THEN N ACROSS PANAMA AND INTO THE W CARIBBEAN. STRONG 
SUBSIDENCE WITH ITS VERY DRY AIR COVERS THE AREA E OF 
105W...MODERATE SUBSIDENCE IS S OF AROUND 10N W OF 105W...THIS 
SUBSIDENCE HAS SUPRESSED CONVCECTIVE ACTIVITY ALONG THE ENTIRE 
LENGTH OF THE ITCZ.

A SURFACE TROUGH IS ANALYZED IN THE GULF OF CALIFORNIA FROM 
24N108W NWD TO A 1015 MB LOW NEAR NOGALES ARIZONA/SONORA. 
ANOTHER TROUGH IS ANALYZED ALONG THE ITCZ FROM 10N127W TO 6N128W.

$$
DGS