000
AXPZ20 KNHC 220343
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 3N78W TO 05N85W TO 05N92W TO 04N108W TO 08N130W TO 
06N140W.  SCATTERED MODERATE CONVECTION WITHIN 75 NM OF AXIS 
FROM 96W-101W.  ISOLATED MODERATE CONVECTION WITHIN 90 NM OF 
AXIS W OF 116W.

...DISCUSSION...
NARROW UPPER LEVEL TROUGH EXTENDED FROM N COSTA RICA TO SMALL 
CYCLONE AT 07N105W THEN S TO 00N105W.  MODERATE TO STRONG MASS 
CONVERGENCE ALOFT BETWEEN TROUGH AND UPSTREAM ANTICYCLONE 
CLOSING IN MAINTAINS MID AND UPPER LEVELS 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.  SERIES OF 
STRONG SHORTWAVES RACE AROUND BASE OF TROUGH HAVE ALREADY MADE 
SIGNIFICANT WEATHER EVENTS OVER SOUTHERN CALIFORNIA.  INFLUX OF 
ABUNDANT MOISTURE EXTENDING IMPACT INTO BAJA CALIFORNIA S OF 30N 
MIGHT BE IN THE WORKS AS TONGUE OF UPPER LEVEL MOISTURE 
APPROACHES BAJA WITHIN NEXT COUPLE OF DAYS.  HOW FAR S OF 30N 
WILL REACH IS STILL UNKNOWN...BUT 28N APPEARS REASONABLE.  

ELSEWHERE AT THE SURFACE...
HIGH PRES CENTER 1012 MB WEAKENED BY THE PUSH AND PULL EXERTED 
BY CONTINUOUS SERIES OF COLD FRONTS MAINTAINS FRESH TRADES W OF 
130W FROM 08N-12N.  TRADES WEAKEN BY LATE FRI.  

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

$$
WALLY BARNES