000
AXPZ20 KNHC 191523
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 19 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 
07N115W TO 07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 
NM OF 07N81.5W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS WITHIN 60 NM OF THE POINT 07N119W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE POINT 
07.5N127W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF 
09N131W.

...DISCUSSION...

STRONG SHORTWAVE IS WEST AND NORTHWEST OF THE AREA AND EXTENDS 
OVER THE AREA NW OF A LINE THROUGH 32N132W TO 24N140W. 
ASSOCIATED SURFACE COLD FRONT IS ALONG LINE THROUGH 32N137W TO 
28N140W. A PLUME OF UPPER LEVEL MOISTURE WITH BROKEN TO OVERCAST 
MOSTLY HIGH CLOUDS IS ALSO ASSOCIATED WITH THE TROUGH AND COVERS 
THE AREA WEST OF 130W. THE MOISTURE EMANATES FROM ITCZ 
CONVECTION WEST OF THE AREA AND GENERAL RISING MOTION ON THE 
EAST FLANK OF THE TROUGH WETS OF THE AREA. THE SHORTWAVE JUST 
NORTHWEST OF THE AREA IS FORECAST TO TRACK EAST REACHING CENTRAL 
CALIFORNIA LATE SUNDAY. THE LARGER TROUGH IS FORECAST TO REMAIN 
STATIONARY AND WEAKEN THROUGH THE NEXT COUPLE OF DAYS.

ANOTHER TROUGH IS OVER THE NORTH HALF OF MEXICO WITH A TROUGH 
AXIS ALONG A LINE THROUGH 26N95W TO THE ITCZ NEAR 115W. 
SOUTHERLY FLOW EAST OF THE TROUGH AXIS IS BRINGING ITCZ MOISTURE 
NORTH OVER MEXICO EAST OF THE TROUGH AXIS AND ALL OF CENTRAL 
AMERICA. MULTIPLE LEVEL OVERCAST TO BROKEN CLOUDS ARE NORTH OF 
THE ITCZ WITH SOME ISOLATED EMBEDDED CONVECTION. STRONG 
SOUTHWESTERLY WINDS IN THE UPPER LEVELS ARE WITHIN 300 NM 
SOUTHEAST OF THE TROUGH AXIS. WINDS REACH TO 120 TO 130 KNOTS IN 
THIS ZONE AND UPPER LEVEL TURBULENCE IS POSSIBLE IN THIS AREA.

FROM 115W TO 135W...THE AREA BETWEEN THE TWO TROUGHS...IS A 
LARGE SCALE DEEP LAYER RIDGE WITH MOSTLY DRY AND CLOUD FREE 
MIDDLE AND UPPER LEVELS. 

DIFFLUENT UPPER FLOW OVER THE ITCZ FROM 115W TO 135W IS CAUSING 
SOME ENHANCEMENT TO THE ITCZ CONVECTION.

OTHER THAN THE COLD FRONT MENTIONED ABOVE A WEAK RIDGE IS NORTH 
OF THE ITCZ WEST OF 108W. ELSEWHERE 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 CHANGE LITTLE THROUGH LATE 
SUN NIGHT.

THE COMBINATION OF STRONG TRADE WINDS IN THE CARIBBEAN AND LOCAL 
DRAINAGE EFFECTS WILL ALLOW FOR NE TO E 20 KT WINDS THROUGH THE 
GULF OF PAPAGAYO TO PULSATE ON AND OFF WITH MAXIMUM PEAK 
OCCURRENCES IN THE MORNINGS INTO EARLY NEXT WEEK.

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