000
AXPZ20 KNHC 192156
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU NOV 19 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 
2100 UTC.

...ITCZ...
AXIS IS ALONG 4N77W 6N90W 7N105W 5N120W 8N140W. SCATTERED 
MODERATE CONVECTION WITHIN 100 NM S OF AXIS FROM 107W-110W. 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 60 NM EITHER SIDE 
OF AXIS W OF 136W. 


...DISCUSSION...
AN UPPER LEVEL TROUGH IS APPROACHING THE FAR NW PORTION OF THE
DISCUSSION AREA. OTHERWISE A BROAD UPPER LEVEL RIDGE COVERS THE 
AREA W OF 110W. THE RIDGE AXIS EXTENDS FROM AN ANTICYCLONIC 
CIRCULATION CENTERED NEAR 11N118W N TO 32N134W...ANOTHER RIDGE 
EXTENDS FROM THE ANTICYCLONIC CIRCULATION NE TO 16N107W. A 
90-105 KT JET STREAM  ENTERS THE AREA AT 24N140W TO 26N125W THEN 
SE ACROSS SOUTHERN TIP BAJA CALIFORNIA THEN INTO CENTRAL MEXICO. 
MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE 
AND UPPER LEVELS IS N OF THE JET. BROKEN TO OVERCAST HIGH CLOUDS 
ARE WITHIN 600 NM S OF THE JET AXIS FROM 140W-130W. DOWNSTREAM 
MID/UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC CIRCULATION OVER 
THE SOUTHERN ROCKIES ACROSS NW MEXICO TO THROUGH SOUTHERN BAJA 
PENINSULA. AN UPPER LEVEL TROUGH E OF THE ANTICYCLONIC 
CIRCULATION IN THE DEEP TROPICS WITH AXIS FROM 15N102W TO 
4N113W. UPPER LEVEL DIFFLUENT FLOW IS ENHANCING CONVECTIVE 
ACTIVITY ALONG THE ITCZ AND A SURFACE TROUGH FROM 6N-9N BETWEEN 
107W-110W. OTHERWISE MODERATE TO STRONG SUBSIDENCE S OF 15N E OF 
120W HAS SUPPRESSED CONVECTION ALONG THE ITCZ IN THIS AREA.

THE PRES GRADIENT HAS WEAKENED ACROSS SOUTHERN MEXICO AND THE 
WINDS HAVE DECREASED TO 20-25 KT IN THE GULF OF TEHAUNTEPEC AND 
WILL CONTINUE TO DECREASE THROUGH THE NEXT 24 HOURS. A 1023 MB 
SURFACE HIGH PRES CENTERED NEAR 31N130W IS PRODUCING STRONG 
ENOUGH GRADIENT FOR WINDS TO REACH 20 TO 25 KT FROM 10N TO 21N W 
OF 120W. BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVER THE AREA 
N OF 20N BETWEEN 115W-135W.

A SURFACE TROUGHS IS ANALYZED ALONG THE ITCZ FROM 14N109W TO 
5N110W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 
107W-110W.

$$
DGS