000
AXPZ20 KNHC 210956
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI NOV 21 2008

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 
0945 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS LIES BETWEEN 06N AND 08N 
E OF 140W. SCATTERED MODERATE CONVECTION IS NOTED ALONG 07N 
BETWEEN 78W AND 86W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE OF LINE FROM 
08N105W TO 07N110W.

...DISCUSSION...

AN UPPER LEVEL TROUGH LIES ALONG 36N122W 33N130W 30N140W AND IS 
ACCOMPANIED BY DRY UPPER AIR ROUGHLY WITHIN 90 NM OF ITS AXIS. A 
SECOND UPPER TROUGH IS NOTED FROM 30N128W TO 22N133W. A BAND OF 
UPPER MOISTURE IS OBSERVED WITHIN 180 NM EITHER SIDE OF POINTS 
26N137W TO 31N123W TO 34N112W. THE UPPER TROUGHS ARE EXPECTED TO 
MERGE ALONG 120W N OF THE EQUATOR IN ABOUT 48 HOURS. AN UPPER 
ANTICYCLONE IS OVER THE SW CARIBBEAN WITH A RIDGE EXTENDING NW 
TO A CREST ALONG 10N118W 20N121W 32N103W. A BAND OF UPPER DRY 
AIR IS NOTED WITHIN 120 NM OF LINE 30N92W 27N114W 19N125W 
07N123W. UPPER DIFFLUENCE ENHANCED ITCZ CONVECTION ALONG 08N 
BETWEEN 100W AND 115W. THE RESULTANT DEBRIS MOISTURE IS ADVECTED 
N UNDER THE RIDGE TO ALONG 18N WHERE MOST OF THE MOISTURE 
EVAPORATES. CONVECTION IS ALSO ENHANCED ALONG 08N E OF 83W WITH 
THE MOISTURE SPREADING N ACROSS CENTRAL AMERICA E OF 90W. 
OTHERWISE THE UPPER LEVELS APPEAR DRY.  

AT THE LOW LEVELS A RIDGE EXTENDS ALONG 32N137W TO 17N112W. 

GAP WINDS...NORTHERLY WINDS IN AND DOWNSTREAM OF THE GULF OF  
TEHUANTEPEC HAVE TEMPORALLY RELAXED TO 20-25 KT. HOWEVER ANOTHER 
COLD SURGE IS FORECAST TO MOVE INTO THE AREA WITH WINDS 
INCREASING TO MINIMAL GALE FORCE THIS MORNING...AND CONTINUING 
TO STRENGTHEN TO A STRONG GALE ON SAT THEN DIMINISHING BELOW 
GALE LATE SUN. NE WINDS ARE AT 20 KT IN THE GULF OF PAPAGAYO AND 
EXPECTED TO INCREASE TO 20 TO 25 KT SAT AND CONTINUE THROUGH SUN 
NIGHT. 

$$
NELSON