000
AXPZ20 KNHC 062113
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT SEP 06 2008

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 
2100 UTC.

...SPECIAL FEATURES...

LOW PRES NEAR 15N105W IS ESTIMATED AT 1003 MB AND IS MOVING W AT 
ABOUT 12 KT. SCATTERED MODERATE TO STRONG CONVECTION IS OBSERVED 
WITHIN 120 NM OF 15N107W. THE LOW IS EXPERIENCING NE SHEAR AT 
THE MOMENT...BUT IS IT IS EXPECTED TO CONTINUE TO TRACK FURTHER 
W CLOSER TO THE UPPER RIDGE AXIS. THIS WILL BE SLIGHTLY MORE 
FAVORABLE FOR INTENSIFICATION INTO A TROPICAL CYCLONE.     

...ITCZ...

ITCZ AXIS IS ALONG 09N78W TO 12N90W LOSING IDENTITY NEAR LOW 
PRES AT 15N105W...THEN CONTINUES FROM 11N105W TO 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 30 NM 
EITHER SIDE OF LINE 12N100W TO 10N106W TO 08N138W. 

...DISCUSSION...

AN UPPER TROUGH LIES ALONG THE NW PERIPHERY OF THE DISCUSSION 
AREA...FROM 32N118W TO 31N130W TO 28N138W INTO A SMALL UPPER 
CYCLONE AT 24N145W. AN UPPER ANTICYCLONE IS CENTERED AT 26N122W 
WITH A RIDGE EXTENDING SW TO A FAIRLY SHARP CREST AT 11N142W.
AN UPPER RIDGE ALSO EXTENDS E ALONG 27N TO ANOTHER UPPER 
ANTICYCLONE OVER NORTHERN OLD MEXICO AT 28N104W. A WEAK UPPER 
TROUGH IS ALONG 22N124W TO 11N133W. THESE UPPER FEATURES COMBINE 
TO DRY OUT THE UPPER LEVELS OF THE DISCUSSION AREA TO THE W OF A 
LINE FROM 30N105W TO 11N130W. AT THE LOW LEVELS A SURFACE RIDGE 
LIES ALONG 32N143W TO 27N115W.

AN UPPER TROUGH DISSECTS THE GULF OF MEXICO ALONG 26N84W TO 
21N98W AND CONTINUING SW OVER THE E PACIFIC INTO A SMALL UPPER 
CYCLONE AT 14N108W. THIS TROUGH IS EXTENDING SW INTO A MUCH A 
LARGER ANTICYCLONIC PATTERN DOMINATING THE DISCUSSION AREA TO 
THE S OF 20N BETWEEN 125W AND 85W. THUS THE UPPER FLOW IS 
PRIMARILY NE IN THIS SAME AREA AND IS ALSO SOMEWHAT DIFFLUENT... 
ENHANCING SCATTERED MODERATE ISOLATED STRONG CONVECTION... 
ASSOCIATED WITH A LOW LEVEL MONSOON TROUGH...ALONG THE COAST OF 
MEXICO FROM 92W TO 100W. CONVECTION IS ALSO ENHANCED AROUND THE 
SURFACE LOW PRES NEAR 15N105W. THE UPPER LEVELS APPEAR MOIST S 
OF 20N BETWEEN 120W AND 84W WITH THE MOISTURE ADVECTED SW WITH 
TIME.   

$$
NELSON