000
AXPZ20 KNHC 311542
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU DEC 31 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...
AXIS IS ALONG 7N78W 5N110W 4N130W 6N140W. SCATTERED MODERATE TO 
STRONG WITHIN 60 NM N AND 90 NM S OF AXIS FROM 80W TO 82W.

...DISCUSSION...
THE FLOW PATTERN IN THE MIDDLE AND UPPER LEVELS WILL CHANGE 
LITTLE IN THE NEXT TWO DAYS. A RIDGE IS OVER THE WESTERN PORTION 
OF THE AREA. THE RIDGE IS N OF THE ITCZ W OF 125W...WITH AXIS 
FROM 32N125W TO 20N140W. AN UPPER LEVEL TROUGH EXTENDS FROM THE 
SW U.S. ACROSS NW MEXICO TO 21N123W. MODERATE TO STRONG 
SUBSIDENCE WITH DRY AND CLOUD FREE STABLE AIR IN THE MIDDLE AND 
UPPER LEVELS IS W OF 120W...THE EXCEPTION IS OVER THE NW PART 
WHERE MULTIPLE LEVEL CLOUDS ARE OBSERVED AHEAD OF A TROUGH W OF 
THE AREA. THE SUBSIDENCE HAS SUPPRESSED ITCZ CONVECTION IN THIS 
AREA. A 95-105 KT JETSTREAM IS SE OF THE UPPER TROUGH FROM 
20N111W THEN NE INTO NORTHERN MEXICO WHERE WINDS INCREASE TO 120 
KT. A PLUME OF DEEP LAYER MOISTURE EXTENDS ABOUT 400 NM E OF THE 
UPPER TROUGH WITH BROKEN TO OVERCAST MOSTLY HIGH CLOUDS OVER 
CENTRAL MEXICO. TO THE E OF THE TROUGH BROAD ANTICYCLONIC FLOW 
IS OBSERVED. THE ANTICYCLONIC CIRCULATION IS CENTERED NEAR 7N88W
WITH RIDGE NWD TO THE YUCATAN PENINSULA. 

SURFACE HIGH PRES IS CENTERED NEAR 29N124W WITH A CENTRAL PRES 
OF 1028 MB. ASSOCIATED MODERATE SURFACE RIDGE IS N OF 12N W OF 
115W. TRADE WINDS N OF THE ITCZ W OF 110W ARE IN THE 20 TO 25 KT 
RANGE FROM NEAR THE ITCZ TO 20N. A 1009 MB SURFACE LOW IS
ANALYZED ALONG THE E PORTION OF THE ITCZ NEAR 6N79W.

N WINDS 20-25 KT ARE BLOWING THROUGH GULF OF TEHUANTEPEC ARE 
FORECAST TO DIMINISH TO LESS THAN 20 KT TONIGHT THEN INCREASE TO 
GALE FORCE ON FRI.

GULF OF PAPAGAYO...E WINDS OF 20 TO 25 KT ARE EXPECTED TO 
CONTINUE THROUGH SAT.

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