000
AXPZ20 KNHC 260958
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED NOV 26 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 EXTENDS FROM 09N84W TO 
05N91W TO 07N115W TO 10N127W TO 08N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 45 NM OF 07.5N83.5W 
AND ALSO WITHIN 60 NM EITHER SIDE OF LINE FROM 07N111W TO 
09N128W.

...DISCUSSION...

A DEEP LAYERED CYCLONE IS AT 32N126W WITH A MID TO UPPER TROUGH 
EXTENDING SW TO BEYOND 19N140W. CONVECTION WAS ENHANCED N OF 30N 
WITHIN 480 NM E OF THE CYCLONE...AND THE DEBRIS MOISTURE IS 
CURRENTLY OBSERVED N OF 29.5N BETWEEN 128W AND 112W...AND IS 
SPREADING N WITH TIME. VERY DRY UPPER AIR IS INDICATED ELSEWHERE 
NW OF LINE 30N112W TO 20N128W TO 17N140W. 

AN UPPER LEVEL ANTICYCLONE HAS FORMED AT 10N115W WITH A 
SHORTWAVE RIDGE EXTENDING NE ALONG 20N108W TO WELL BEYOND 
32N103W. A MOISTURE PLUME ORIGINATING FROM CENTRAL PACIFIC ITCZ 
CONVECTION IS ADVECTED E NE ENTERING THE DISCUSSION AREA WITHIN 
210 NM EITHER SIDE OF LINE 14N140W TO 16N124W...WHERE IT MERGES 
WITH MOISTURE FROM ITCZ CONVECTION BETWEEN 117W AND 130W WHICH 
IS SPREADING N UNDER THE RIDGE. AT THE LOW LEVELS...A SERIES OF 
COLD SURGES FROM THE NW AND A PERSISTENT LOW LEVEL TROUGH HAS 
MERGED INTO A BROAD TROUGH OVER THE AREA FROM 12N TO 22N BETWEEN 
115W AND 125W. ISOLATED MODERATE AND STRONG CONVECTION IS 
ENHANCED IN THIS AREA. THE RESULTANT DEBRIS MOISTURE FROM THIS 
CONVECTION IS MERGING WITH THE PLUME APPROACHING FROM THE 
CENTRAL PACIFIC. THUS A LARGE TROPICAL PLUME IS STREAMING NE 
WITHIN 330 NM EITHER SIDE OF LINE FROM 16N120W TO BEYOND 32N103W 
EVENTUALLY FANNING OUT OVER THE CENTRAL CONUS.

TO THE E OF THE RIDGE...A LONGWAVE TROUGH IS WELL DEFINED FROM 
32N81W TO 19N95W INTO AN UPPER CYCLONE AT 11N109W WITH THE 
TROUGH EXTENDING S OF THE EQUATOR ALONG 104W. AN UPPER 
ANTICYCLONE NEAR 06N78W HAS A RIDGE EXTENDING W TO NEAR 13N103W.
BROAD LOW PRESSURE OVER THE SW CARIBBEAN PERSISTS WITH A LOW 
LEVEL TROUGH EXTENDING W ACROSS CENTRAL AMERICA INTO THE PACIFIC 
ALONG 10N85W TO 07N91W. CONVECTION IS CURRENTLY ENHANCED OVER 
THE PACIFIC NEAR 07N84W...BUT THE DEBRIS MOISTURE IS ADVECTED NE 
ACROSS THE CENTRAL CARIBBEAN. A BAND OF DRY UPPER AIR IS NOTED 
WITHIN 300 NM EITHER SIDE OF POINTS 28N82W TO 20N96W TO 08N109W.

GAP WINDS...NORTHERLY WINDS IN AND DOWNSTREAM OF THE GULF OF  
TEHUANTEPEC ARE CURRENTLY AT 25 TO 35 KT WITH SEAS TO AROUND 12 
FT. EXPECT THAT A FINAL NORTHERLY SURGE WILL OCCUR AFTER SUNRISE 
IN THAT AREA TODAY THEN CONDITIONS WILL DIMINISH. LOW PRES IS 
EXPECTED TO DEVELOP ALONG THE TROUGH MENTIONED ABOVE TO THE SW 
OF COSTA RICA. THE NE WINDS IN THE GULF OF FONSECA AND PAPAGAYO 
WILL CONTINUE TODAY THEN DIMINISH N OF 12N TONIGHT BUT CONTINUE 
OVER THE N SEMICIRCLE OF THE LOW INCLUDING THE GULF OF PAPAGAYO 
IN RESPONSE TO THE LOW PRESSURE FOR A FEW DAYS.

$$
NELSON