000
AXPZ20 KNHC 312147
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 31 2009

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 
2145 UTC.

...ITCZ...
AXIS IS ALONG 06N78W 04N85W 08N100W 05N125W 06N140W. SCATTERED 
MODERATE WITHIN 60 NM OF AXIS FROM 80W TO 83W.

...DISCUSSION...
FAIRLY STABLE FLOW PATTERN IN EVIDENCE ACROSS THE EAST PACIFIC 
WITH LITTLE CHANGE EXPECTED OVER THE NEXT COUPLE OF DAYS. RATHER 
FLAT RIDGE IS OVER THE WESTERN PORTION OF THE AREA...GENERALLY 
N OF THE ITCZ AND W OF 125W...WITH AXIS FROM 32N125W TO 18N140W. 
AN UPPER LEVEL TROUGH EXTENDS FROM THE SW U.S. ACROSS NW MEXICO 
TO A SHEARED CYCLONIC CIRCULATION NEAR 20N121W. 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 MULTILAYERED CLOUDS ARE OBSERVED AHEAD OF A TROUGH 
NW OF THE AREA. THE SUBSIDENCE HAS SUPPRESSED ITCZ CONVECTION IN 
THIS AREA. A 90-110 KT JETSTREAM IS SE OF THE UPPER TROUGH FROM 
20N112W EXTENDING NE THROUGH NORTHERN MEXICO INTO THE GULF OF 
MEXICO WHERE WINDS INCREASE TO 120 KT IN AN AREA OF GENERAL 
CONFLUENCE. 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 1028 MB IS CENTERED NEAR 29N124W. ASSOCIATED 
SURFACE RIDGE IS N OF 12N W OF 110W. 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.

GAP WINDS...
MOST RECENT ASCAT PASS INDICATED N WINDS OF 20 KT IN THE GULF OF 
TEHUANTEPEC. THESE WINDS WILL BRIEFLY DECREASE BELOW 20 KT 
TONIGHT BEFORE INCREASING AGAIN EARLY FRI AND REACHING GALE 
FORCE BY LATE FRI INTO SAT.  

GULF OF PAPAGAYO...E WINDS OF 20 TO 25 KT ARE EXPECTED TO 
CONTINUE THROUGH SAT. BUILDING HIGH PRESSURE OVER CENTRAL AMERICA
MAY ENHANCE THE AREA OF WINDS BY SAT. 
 
FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE
  
$$
COBB