000
AXPZ20 KNHC 210905
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED JAN 21 2009

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 
0900 UTC.

...ITCZ...
AXIS ALONG 04N78W TO 06N110W TO 04N130W TO 06N140W. NO 
SIGNIFICANT CONVECTION.

...DISCUSSION...
A BROAD UPPER LEVEL RIDGE OVER THE WESTERN PORTION OF THE 
DISCUSSION AREA WITH AXIS FROM 32N136W TO 10N140W. ANTICYCLONIC 
FLOW COVERS THE AREA W OF 130W. MODERATE TO STRONG SUBSIDENCE 
WITH DRY STABLE AIR AT THE MIDDLE AND UPPER LEVELS OF THE 
ATMOSPHERE IS W OF 125W. A 90-100 KT JET STREAM IS OVER THE TOP 
OF THE RIDGE FROM 32N140W TO 30N130W. MID TO UPPER LEVEL TROUGH 
IS E OF THE RIDGE FROM 32N123W TO 25N118W TO CYCLONIC 
CIRCULATION CENTERED NEAR 15N117W. MID/UPPER LEVEL RIDGE WITH 
AXIS FROM EASTERN ARIZONA ACROSS WESTERN MEXICO TO 15N100W. 
MODERATE TO STRONG SUBSIDENCE COVERS THE AREA S OF 20N E OF 
100W...WITH MOSTLY CLEAR SKIES EXCEPT FOR BROKEN TO OVERCAST 
STRATOCUMULUS CLOUDS S OF THE ITCZ.

A 1012 MB SURFACE LOW IS CENTERED NEAR 27N126W WITH TROUGH FROM 
THE LOW TO 20N107W 17N130W. DISSIPATING COLD FRONT W OF THE 
TROUGH EXTENDS FROM 32N127W TO 18N133W THEN STATIONARY TO 
16N140W. OVERCAST LOW TOP CLOUDS WITH AREAS OF LIGHT RAIN ARE 
BETWEEN THE TROUGH AND THE FRONT N OF 25N. A COUPLE HIGH PRES 
CENTERS ARE ANALYZED ACROSS THE AREA...ONE 1021 MB HIGH NEAR 
29N140W AND ANOTHER 1018 MB HIGH NEAR 22N115W. HIGH PRES 
BUILDING BEHIND A COLD FRONT IN THE GULF OF MEXICO HAS TIGHTENED 
THE PRES GRADIENT OVER SOUTHERN MEXICO WITH GALE FORCE WINDS 
BLOWING THROUGH THE GULF OF TEHUANTEPEC.

$$
DGS