000
AXPZ20 KNHC 211531
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 21 2008

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...
THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 08N83W TO 
08N110W TO 09N115W TO 06N140W. SCATTERED MODERATE CONVECTION IS  
WITHIN 100 NM S OF AXIS BETWEEN 100W AND 115W. SIMILAR 
CONVECTION IS NEAR 07N82W...AND NEAR 14N112W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM 30N128W TO 21N130W. A SECOND 
UPPER TROUGH IS NOTED FROM 21N120W TO 09N117W. MID/UPPER LEVEL 
MOISTURE IS AHEAD OF BOTH TROUGHS THAT ARE EXPECTED TO MERGE 
ALONG 120W N OF THE EQUATOR LATE SAT. AN UPPER-LEVEL RIDGE 
ANCHORED ON A HIGH OVER THE SW CARIBBEAN DOMINATES THE EPAC EAST 
OF 105W. UPPER DIFFLUENCE BETWEEN THIS RIDGE AND THE EASTERNMOST 
TROUGH IS ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 100W AND 
115W. ANOTHER UPPER-LEVEL RIDGE CENTERED WEST OF THE FORECAST 
REGION IS PRODUCING SUBSIDENCE/DRY AIR ACROSS MUCH OF THE AREA S 
OF 20N W OF 120W EXCEPT ALONG THE ITCZ AXIS.   
 
AT THE SURFACE...A 1030 MB HIGH LOCATED N OF AREA NEAR 35N135W 
EXTENDS A RIDGE OVER THE DISCUSSION AREA COVERING N OF 7N AND 
WEST OF 125W. THIS FEATURE IS PRODUCING A BELT OF TRADE WINDS IN 
THE 20 T0 25 KT RANGE MAINLY BETWEEN 7N AND 22N. AN EARLIER 
ASCAT PASS COMFIRMED THESE WIND SPEEDS.   

GAP WINDS...NORTHERLY WINDS IN AND DOWNSTREAM OF THE GULF OF  
TEHUANTEPEC HAVE REACHED GALE FORCE THIS MORNING. A QSCAT PASS 
FROM AROUND 1230 UTC SHOWED A COUPLE OF 30 TO 35 KT WIND BARBS. 
THESE WINDS ARE EXPECTED TO PERSIST DURING THE UPCOMING WEEKEND 
AS ANOTHER COLD SURGE MOVES INTO THE AREA WITH WINDS INCREASING 
TO A STRONG GALE ON SAT THEN DIMINISHING BELOW GALE LATE SUN. 

NE WINDS OF 20 TO 25 KT ARE IN THE GULF OF PAPAGAYO AND THESE 
CONDITIONS ARE EXPECTED TO CONTINUE AND SPREAD WWD SAT THROUGH 
SUN NIGHT. 

$$
GR