000
AXPZ20 KNHC 250331
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON OCT 25 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 10N85W TO 07N94W TO 10N112W TO 
08N120W TO 10N140W. ISOLATED MODERATE CONVECTION IS OBSERVED NE 
OF A LINE FROM 02N79W TO 08N95W TO THE COAST OF CENTRAL AMERICA. 
SCATTERED MODERATE WITHIN 60 NM EITHER SIDE OF A LINE FROM 
11N112W TO 09N121W AND ALSO WITHIN 75 NM OF 09N139W.

...DISCUSSION...

AN UPPER TROUGH FROM 32N95W TO 24N106W TO 15N129W. AN UPPER 
ANTICYCLONE IS CENTERED AT 32N145W WITH A RIDGE COLLAPSING SE TO 
A CREST AT 31N105W. UPPER MOISTURE IS INDICATED OVER THE 
AREA N OF 29N W OF 113W...WITH MOISTURE NOTED OVER MOST OF THE 
SW CONUS. OTHERWISE THE UPPER LEVELS ARE VERY DRY ACROSS THE 
SUBTROPICS...N OF 23N. THE UPPER TROUGH IS EXPECTED TO LEAVE CUT 
OFF AN UPPER CYCLONE NEAR 18N135W BY TUE WITH AN UPPER 
ANTICYCLONE DEVELOPING 19N114W. 

AN UPPER CYCLONE IS OBSERVED NEAR 05N129W AND IS PROGRESSING W 
WITH TIME. AN UPPER TROUGH EXTENDS ENE FROM THE CYCLONE TO NEAR 
14N112W. THIS CYCLONE AND TROUGH EFFECTIVELY SEPARATE THE UPPER 
FLOW OVER THE TROPICAL E PACIFIC. TO THE W AN UPPER ANTICYCLONE 
IS CENTERED AT 13N141W WITH A RIDGE EXTENDING E TO A SHARP CREST 
AT 13N129W. UPPER DIFFLUENCE S OF THIS RIDGE IS ENHANCING THE 
CONVECTIVE CLUSTER NEAR 09N139W WITH THE DEBRIS MOISTURE 
SPREADING OUT FROM 06N TO 11N BETWEEN 132W AND 142W. THE UPPER 
TROUGH IS ENHANCING CONVECTION ALONG THE ITCZ ALONG THE LINE 
FROM 11N112W TO 09N121W...BUT THE DEBRIS MOISTURE REMAINS 
WITHIN A FEW DEGREES OF THE CONVECTION AS THE UPPER LEVELS 
APPEAR VERY DRY OVER THE ENTIRE AREA S OF 23N W OF 95W. 

THE UPPER ANTICYCLONE ASSOCIATED WITH HURRICANE RICHARD IN THE 
NW CARIBBEAN HAS ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING 
ACROSS CENTRAL AMERICA WITH A RIDGE EXTENDING W TO A CREST OVER 
THE TROPICAL PACIFIC AT 16N108W. THE UPPER DIFFLUENCE IS 
ENHANCING CONVECTION OVER MOST OF THE WESTERN CARIBBEAN AND 
CENTRAL AMERICA...AND THE ISOLATED CONVECTION OVER THE PACIFIC 
WATERS AS PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE IS SPREADING 
W OVER THE DISCUSSION AREA N OF 07N E OF 95W.
 
ELSEWHERE AT THE SURFACE...HIGH PRES CENTERED NEAR 25N145W HAS A 
RIDGE EXTENDING E TO NEAR 15N107W. A VERY DRY COLD FRONT IS 
RACING ACROSS THE PACIFIC WATERS N OF THIS RIDGE BUT THE 
ASSOCIATED WIND SHIFT IS VERY MINOR PER GUIDANCE WITH THE RIDGE 
EXPECTED TO REBUILD GRADUALLY IN THE WAKE OF THE FRONT. STRONG N 
WINDS DO NOT ARRIVE ALONG 31N TILL LATE MON REACHING ALONG 24N E 
OF 125W LATE TUE NIGHT ACCOMPANIED BY SEAS TO 16 FT NEAR 
30N120W. IN THE MEANTIME THE PRES GRADIENT S OF THE RIDGE AND N 
OF THE ITCZ IS PRODUCING AN AREA OF FRESH NE TRADE WINDS BETWEEN 
10N AND 20N W OF 122W. EXPECT THIS AREA TO SHIFT N AS THE RIDGE 
AXIS SHIFT N TO ALONG 31N MON NIGHT. MONSOONAL SW FLOW CONTINUES 
S OF 10N E OF 105W WITH SW WINDS 15 TO 20 KT FROM 05N TO 12N E 
OF 110W. 

$$
NELSON