000
AXPZ20 KNHC 192202
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED DEC 19 2007

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 
2100 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE ALONG 8N77W  7N120W  7N140W. 
SCATTERED MODERATE CONVECTION WITHIN 90 NM N OF AXIS 105-110W.

...DISCUSSION...
MID-LATITUDE UPPER LEVEL RIDGE HAS AXIS ALONG CENTRAL AMERICA 
WITH 120 KT JET CORE RIDING OVER ITS CREST ACROSS CENTRAL TEXAS. 
JTST BRINGS PLENTY OF TRPCL MOISTURE INTO NRN MEXICO AND SRN 
CENTRAL PLAINS IN CONUS...BUT OTHERWISE VERY DRY S OF 24N E OF 
110W.  

MID-UPPER CYCLONIC VORTEX AT 23N133W HAS UPPER LEVEL TROUGH 
EXTEND SE TO SECOND CYCLONE WHIRL AT 5N109W.  DEFORMATION ZONE 
IN MIDST OF TROUGH HAS SUFFICIENT UPPER DIFFLUENCE TO BRING LOW 
LEVEL TRPCL MOISTURE TO HIGHER LEVELS AND FEED SWATH ADVECTING 
NE IN JTST.  MID-UPPER LEVEL RIDGE WITH WEAK JET CORE OVER ITS 
CREST N OF 25N JUST WEST OF 140W ALSO BRINGS MOISTURE INTO E PAC 
SCENE BUT WITH LITTLE OR NO UPLIFT MECHANISM SINCE 1026 MB 
SURFACE HIGH PRES RIDGE DOMINATE ENTIRE E PAC WATERS.  

AT THE SURFACE...WELL ANCHORED HIGH PRES CENTER DIVERTS WEAK 
COLD FRONT JUST N OF 30N PREVENTING ANY FURTHER SOUTHWARD 
INTRUSION BUT ALLOWING NW FLOW OVER GULF OF CALIFORNIA N OF 25N 
TO INCREASE FOR SHORT PERIOD OF TIME.  

NE TRADES REMAIN AT CLIMATOLOGICAL MEAN FROM 10N-20N W OF 120W.  
GULF OF TEHUANTEPEC EVENT WINDS DOWN WITHIN 24-30 HRS AS DOES 
GULF OF PAPAGAYO GAP WINDS. 

$$
WALLY BARNES