000
AXPZ20 KNHC 280341
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI AUG 28 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 
0315 UTC.

...SPECIAL FEATURES...

.BROAD LOW PRES NEAR 10N115W IS ANALYZED AT 1009 MB. WINDS HAVE 
INCREASED TO 20 TO 25 KT WITHIN ROUGHLY 300 NM OF CENTER. 
CURRENTLY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
BANDING OVER THE NW QUADRANT OF THE CENTER...WITHIN 60 NM EITHER 
SIDE OF A LINE FROM 14N112W TO 11N117W. THE LOW IS EXPECTED TO 
MOVE W NW OVER THE NEXT FEW DAYS AND POSSIBLY DEVELOP INTO A 
TROPICAL CYCLONE.  

.LOW PRES HAS FORMED NEAR 14N97W AT AN ESTIMATED 1007 MB AND IS  
ASSOCIATED WITH A TROPICAL WAVE LOCATED N OF 06N ALONG 97W. 
WINDS ARE NE TO E AT 20 KT WITHIN 180 NM OF CENTER OVER THE N 
SEMICIRCLE. THE LOW IS EXPECTED TO TRACK JUST N OF DUE W FOR A 
COUPLE OF DAYS...THEN ACCELERATE TO THE NW. TROPICAL CYCLONE 
DEVELOPMENT IS POSSIBLE.

...TROPICAL WAVES...

A TROPICAL WAVE IS N OF 05N ALONG 81W AND IS MOVING W AT 15 KT.
ISOLATED MODERATE AND STRONG CONVECTION IS NOTED TO THE N OF 05N 
E OF 85W BUT IS CURRENTLY DECREASING IN COVERAGE AND INTENSITY.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS ALONG 08N81W TO 
11N97W TO 09N116W TO 07N121W TO 14N131W TO 12N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM LINE 
FROM 06N87W TO 09N110W. SCATTERED MODERATE CONVECTION IS NOTED 
FROM 07N TO 13N BETWEEN 118W AND 125W AND ALSO FROM 07N TO 12N W 
OF 137W.

...DISCUSSION...

AN UPPER ANTICYCLONE NEAR 19.5N124W HAS A RIDGE SW TO NEAR 
13N138W AND A RIDGE E TO NEAR 20N113W. A SECOND ANTICYCLONE IS 
NEAR 30N120W WITH A SHARP RIDGE S TO 17N118W. UPPER MOISTURE IS 
TRAPPED UNDER THE RIDGE ALONG 120W TO THE N OF 15N...BUT SEEMS 
TO BE EVAPORATING. AN UPPER TROUGH HAS NEARLY STALLED OVER THE 
NW PORTION OF THE AREA ROUGHLY ALONG 33N135W TO 27N137W...AND IS 
ACCOMPANIED BY UPPER MOISTURE W OF ITS AXIS. SOME DEBRIS 
MOISTURE FROM FORMER TROPICAL DEPRESSION IGNACIO HAS MOVED N TO 
NEAR 32N131W.  OTHERWISE THE UPPER LEVELS AREA DRY N OF 17N W OF 
122W.

AN UPPER ANTICYCLONE IS NEAR 18N96W WITH ITS ENVELOPE OF 
ANTICYCLONIC FLOW EXTENDING S OVER THE TROPICAL PACIFIC BETWEEN 
90W AND 110W...AND IS ENHANCING CONVECTION ALONG THE LOW PRES 
AND TROPICAL WAVE ALONG 97W...BOTH PREVIOUSLY MENTIONED. THE 
ASSOCIATED MOISTURE REMAINS N OF 05N.

ELSEWHERE AT THE SURFACE...HIGH PRES IS NEAR 23N120W.

$$
NELSON