000
AXPZ20 KNHC 252148
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON OCT 25 2010

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 
2145 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 08N83W TO 07N94W TO 12N114W TO 
08N124W TO 10N132W TO 09N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 30 NM EITHER SIDE OF LINES 
FROM 13N113W TO 10N120W AND FROM 09N134W TO 08N140W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM 28N101W TO 23N110W TO AN UPPER 
CYCLONE AT 21N129W WITH THE TROUGH CONTINUING SW INTO ANOTHER 
UPPER CYCLONE AT 14N138W. AN UPPER ANTICYCLONE IS CENTERED AT 
31N135W WITH A RIDGE COLLAPSING SE TO A CREST AT 31N101W. UPPER 
MOISTURE IS INDICATED OVER THE AREA N OF 29N E OF 130W...WITH 
DENSE MOISTURE NOTED OVER MOST OF THE SW CONUS. OTHERWISE THE 
UPPER LEVELS ARE VERY DRY ACROSS THE SUBTROPICS...N OF 23N W OF 
92W. THE UPPER CYCLONE AT 14N138W IS EXPECTED TO CUT OFF FROM 
THE UPPER TROUGH TUE AND MOVE N ALONG 138W TUE NIGHT AND WED AS 
THE UPPER ANTICYCLONE MOVES S AND MERGES WITH ANOTHER 
ANTICYCLONE NEAR 18N115W.

AN UPPER CYCLONE IS OBSERVED NEAR 04N131W AND IS PROGRESSING W 
WITH TIME. AN UPPER TROUGH EXTENDS NE FROM THIS CYCLONE TO NEAR 
13N123W. AN UPPER RIDGE EXTENDS E ACROSS THE ITCZ W OF 132W WITH 
ITS UPPER DIFFLUENCE ENHANCING THE ITCZ CONVECTION FROM 09N134W 
TO 08N140W WITH THE DEBRIS MOISTURE REMAINING OVER THE 
CONVECTIVE CLUSTERS.

AN UPPER ANTICYCLONE IS CENTERED NEAR 18N109W HAS A RIDGE 
EXTENDING W TO A CREST AT 13N122W. THE ASSOCIATED UPPER 
DIFFLUENCE IS ENHANCING CONVECTION ALONG THE LINE FROM 13N113W 
TO 10N120W WITH THE DEBRIS SPREADING N AND EVAPORATING ALONG 
15N. 

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM 30N130W TO 
14N107W. A DRY COLD FRONT EXTENDS ALONG 32N BETWEEN 120W AND 
130W. NORTHERLY WINDS AT 20 TO 25 KT AND SEAS TO 15 FT WILL PUSH 
S OVER THE PACIFIC WATERS N OF 24N E OF 126W TUE. THE PRES 
GRADIENT S OF THE RIDGE AND N OF THE ITCZ IS PRODUCING AN AREA 
OF FRESH NE TRADE WINDS BETWEEN 09N AND 21N W OF 126W. ANOTHER 
COLD FRONT WILL APPROACH THE NW PORTION ON WED WITH SEAS 
BUILDING TO 15 FT OVER THE NW WATERS BY FRI. MONSOONAL SW FLOW 
AT 15 TO 20 KT CONTINUES FROM 04N TO 09N BETWEEN 85W AND 100W.

$$
NELSON