000
AXPZ20 KNHC 221516
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE DEC 22 2009

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...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...07N78W TO 
04N95W TO 06N115W 08N140W. SCATTERED MODERATE CONVECTION IS EAST 
OF 79W.

...DISCUSSION...

FULL LATITUDE TROUGH MOSTLY WEST AND NORTHWEST OF THE AREA 
EXTENDS OVER THE NORTHWEST PART OF THE AREA NW OF A LINE THROUGH 
32N135W TO 25N140W. A SMALL TRANSIENT CYCLONIC CIRCULATION IS 
LOCATED WITHIN THIS TROUGH AND IS CENTERED NEAR 29N140W. A 
ANOTHER STRONG SHORTWAVE IS FURTHER WEST AND WILL MOVE INTO THE 
MAIN TROUGH AND KEEP THE PATTERN THROUGH THE NEXT COUPLE OF 
DAYS. ANOTHER STRONG SHORTWAVE IS MOVING EAST JUST TO THE WEST 
OF NORTHERN BAJA CALIFORNIA WITH AND ASSOCIATED SURFACE COLD 
FRONT IS ALONG LINE THROUGH 32N115W TO 25N118W. A PLUME 
OF UPPER LEVEL MOISTURE WITH BROKEN TO OVERCAST MIDDLE AND HIGH 
CLOUDS IS ALSO ASSOCIATED WITH THE TROUGH AND COVERS THE PACIFIC 
OCEAN AREA WITHIN 300 NM EITHER SIDE OF A LINE FROM 24N120W TO 
20N132W TO 11N140W. THE MOISTURE EMANATES FROM ITCZ CONVECTION 
WEST OF 130W AND ALSO DUE TO THE GENERAL RISING MOTION ON THE 
EAST FLANK OF THE TROUGH. MOISTURE AND MULTIPLE LEVEL BROKEN TO 
OVERCAST CLOUDS ARE OVER MEXICO NORTH OF 24N AND ARE ASSOCIATED 
WITH THE SHORTWAVE APPROACHING FROM THE WEST. 

ANOTHER TROUGH IS OVER EASTERN MEXICO WITH A NEGATIVELY TILTED 
TROUGH AXIS FROM THE YUCATAN PENINSULA NEAR 21N88W TO 
SOUTHWESTERN COLOMBIA. SOUTHERLY FLOW EAST OF THE TROUGH AXIS IS 
BRINGING MOISTURE FROM ITCZ CONVECTION NORTH OVER CENTRAL 
AMERICA EAST OF COSTA RICA. DRYING IS NOTED OVER COSTA RICA 
WESTWARD AS THE TROUGH SWINGS EAST. IN THIS MOIST REGION 
MULTIPLE LEVEL OVERCAST TO BROKEN CLOUDS ARE NORTH OF THE ITCZ 
WITH SOME EMBEDDED CONVECTION.  

WEST OF THE TROUGH AXIS AND EAST OF THE MOISTURE MENTIONED IN 
THE FIRST PARAGRAPH...THAT IS THE AREA BETWEEN THE TWO TROUGHS 
...IS A LARGE SCALE DEEP LAYER WEAKENING RIDGE WITH MOSTLY DRY 
AND CLOUD FREE MIDDLE AND UPPER LEVELS. 

OTHER THAN THE COLD FRONT MENTIONED ABOVE A WEAK RIDGE IS NORTH 
OF 15N. WEAK LOW PRESSURE 1011 MB IS CENTERED NEAR 14N124W WITH 
A BROAD TROUGH SOUTH TO THE ITCZ. OTHERWISE A BROAD TROUGH 
CENTERED ON THE ITCZ IS ANALYZED AT THE SURFACE.

GAP N TO NE WINDS OF 20 TO 25 KT ARE OCCURRING THROUGH THE GULF 
OF TEHUANTEPEC AND ARE EXPECTED TO DIMINISH TODAY.

GAP WINDS IN THE GULF OF PAPAGAYO REGION HAVE DIMINISHED.

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