000
AXPZ20 KNHC 212208
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JAN 21 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...ITCZ...
AXIS ALONG 302N79W TO 06N88W TO 04N110W TO 08N130W TO 07N140W.  
ISOLATED MODERATE WITHIN 90 NM OF AXIS FROM 96W TO 100W.

...DISCUSSION...
NARROW UPPER LEVEL TROUGH EXTENDED FROM N COSTA RICA TO SMALL 
CYCLONE AT 07N103W THEN TO 00N107W.  MODERATE TO STRONG 
DIVERGENCE ALOFT BETWEEN TROUGH AND UPSTREAM ANTICYCLONE CLOSING 
IN MAINTAINS AIR MASS FAIRLY DRY AND STABLE WITH ONLY SCATTERED 
STRATIFIED LOW CLOUDS N OF 10N ACROSS ENTIRE BASIN.  MINOR 
CONVECTION ALONG ITCZ DECREASING IN INTENSITY AND COVERAGE AS 
DRYNESS EXTENDS EASTWARD WITH UPPER ANTICYCLONE.

POLAR CYCLONIC VORTEX WELL N OF REGION HAS HEALTHY NEGATIVE TILT 
TROUGH EXTENDING SE TO NORTHERN BAJA CALIFORNIA.  STRONG 
SHORTWAVE RACING AROUND BASE OF TROUGH THAT HAS MADE SIGNIFICANT 
WEATHER EVENT OVER SOUTHERN CALIFORNIA WANTS TO EXTEND IMPACT TO 
BAJA CALIFORNIA S OF 30N BUT CONTINUED LACK OF MOISTURE CURTAILS 
MAGNITUDE OF EVENT.  DEEPLY ENTRENCHED UPPER NEGATIVE TILT 
TROUGH REMAINS IN POSITION ALLOWING SERIES OF SHORTWAVES TO 
CONTINUE POUNDING WESTERN CONUS COAST THROUGH NEXT 48 HRS. 

ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER 1014 MB PUSHED AND PULLED BY CONTINUOUS FLOW OF 
COLD FRONTS MAINTAINS FRESH TRADES W OF 130W FROM 08N-14N.  
TRADES WEAKEN BY LATE FRI.  

GAP WINDS PREVIOUSLY AFFECTING GULFS OF PAPAGAYO AND PANAMA HAVE 
DIMINISH BELOW 20 KT.  

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALLY BARNES