000
AXPZ20 KNHC 240314
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT OCT 24 2009

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 
0330 UTC.

...TROPICAL LOW...
THE SOUTHERN EXTENT OF AN ATLANTIC AND CARIBBEAN UPPER TROUGH 
TERMINATES OVER THE E PACIFIC NEAR 09N90W. THE RESULTANT BROAD 
AREA OF LOW PRESSURE IS ANALYZED AS A SURFACE LOW PRESSURE AT 
08N85W AT AN ESTIMATED 1007 MB. SEVERAL CYCLONIC SWIRLS ARE 
OBSERVED S OF 10N BETWEEN 93W AND 83W AND CONVECTION REMAINS 
UNORGANIZED.   

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N78W TO 
08N94W TO 12N108W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 150 NM EITHER SIDE OF A LINE FROM 
08N88W TO 09N102W AND ALSO ANOTHER LINE FROM 14N106W TO 10N120W 
TO 11N140W.

...DISCUSSION...
AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 32N135W WITH A RIDGE 
EXTENDING SSE TO A SHARP CREST AT 27N125W. A TROPICAL 
ANTICYCLONE IS CENTERED AT 11N129W WITH A RIDGE AMPLIFYING N TO 
22N132W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION 
ALONG THE ITCZ BETWEEN 126W AND 149W. SOME OF THE DEBRIS 
MOISTURE IS ADVECTED N UNDER THE RIDGE BUT EVAPORATES BEFORE 
REACHING 22N. A THIRD ANTICYCLONE IS OVER THE S CENTRAL GULF OF 
MEXICO AT 22N88W WITH A RIDGE EXTENDING SW OVER THE THE E 
PACIFIC TO A CREST AT 11N105W...RESULTING IN A BROAD UPPER RIDGE 
OVER THE TROPICAL PACIFIC BETWEEN 90W AND 105W. DEBRIS MOISTURE 
FROM ITCZ CONVECTION BETWEEN 106W AND 120W IS ADVECTED NE ALONG 
THE NW PERIPHERY OF THIS TROPICAL RIDGE BECOMING A PLUME OVER 
OLD MEXICO FROM 20N104W ACROSS SE TEXAS TO CENTRAL LOUISIANA.

THE DISCUSSION AREA BETWEEN THESE ANTICYCLONES IS DOMINATED BY 
THE SOUTHERN EXTENSION OF A LONG WAVE TROUGH THAT DISSECTS 
CENTRAL N AMERICA AND EXTENDING INTO THE DISCUSSION AREA ALONG 
32N103W TO 16N118W. EXCEPT AS MENTIONED...VERY DRY UPPER AIR IS 
INDICATED N OF 17N W OF 110W AND OVER NORTHWESTERN OLD MEXICO. 

AT THE LOW LEVELS HIGH PRES IS CENTERED N OF THE AREA NEAR 
34N136W WITH A RIDGE EXTENDING SE TO NEAR 17N112W. THE GRADIENT 
NE OF THE RIDGE IS SUPPORTING NORTHERLY WINDS TO 20 KT WHILE THE 
GRADIENT SW OF THE RIDGE IS SUPPORTING NE TRADES AT 20 TO 25 KT. 
N AND NW SWELLS ARE MIXING OVER THE SUBTROPICAL WATERS. 

$$
NELSON