000
AXPZ20 KNHC 200915
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN DEC 20 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
AXIS IS ALONG 9N84W 7N100W 9N120W 8N140W. NO SIGNIFICANT 
CONVECTION.

...DISCUSSION...
UPPER LEVEL RIDGING PREVAILS ALONG THE W PART OF THE DISCUSSION 
AREA WITH AXIS FROM 32N120W TO 5N126W. A 100-120 KT JETSTREAM 
ENTERS THE AREA AT 27N140W TO 32N132W. THE SW JET IS ADVECTING 
TROPICAL MOISTURE NWD ACROSS THE RIDGE. THE JET CURVES AROUND
THE RIDGE WITH NW WINDS 95-100 KT FROM 32N117W ACROSS BAJA
CALIFORNIA TO 16N109W. A SHARP UPPER LEVEL TROUGH EXTENDS FROM
THE BIG BEND OF TEXAS ACROSS CENTRAL MEXICO TO 5N107W. A 95-105 
KT JETSTREAM IS E OF THE TROUGH FROM 16N102 ACROSS SOUTHERN
MEXICO INTO THE GULF OF MEXICO. THIS JET IS ALSO ADVECTING
TROPICAL MOISTURE NWD INTO SOUTHERN MEXICO.

COLD FRONT IS IN THE FAR NW PART OF THE AREA EXTENDS FROM 
32N134W TO 26N140W. THE COLD FRONT WILL WEAKEN AND BECOME 
DIFFUSE WITHIN THE NEXT 24 HOURS BUT LONG PERIOD NW SWELL THAT 
GENERATED BEHIND THIS FRONT WILL SPREAD S AND E ACROSS THE AREA 
MAINLY N OF 08N AND W OF 117W. A 1018 MB HIGH PRES IS CENTERED 
NEAR 29N129W. THE PRES GRADIENT BETWEEN THIS FEATURE AND THE 
ITCZ IS PRODUCING MODERATE TO STRONG TRADEWIND FLOW FROM 9N-14N 
W OF 125W.

N TO NE WINDS OF 20 TO 25 KT ARE OCCURRING THROUGH THE GULF OF 
TEHUANTEPEC AND ARE EXPECTED TO CHANGE LITTLE THROUGH LATE MON 
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
  
$$
DGS