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Area forecast discussion...updated aviation 
National Weather Service St Louis MO 
713 PM CDT Sat Jul 5 2008 


Discussion... 
/256 PM CDT Sat Jul 5 2008/ 
surface ridge of high pressure extended from the Great Lakes region 
across east MO. Dewpoints remained in the 50s for a very comfortable 
day for early July. System will retreat into the New England states 
which will allow a warm front to move across the region Sunday 
night. 


The next cold front is forecast to extend from the upper Midwest 
across southeast Nebraska into western Kansas by Tuesday morning. The GFS and 
European model (ecmwf) are now fairly similar in forecasting that the front will sag 
into the region by Tuesday night. The two models are similar in 
forecasting that a short wave will roll across the Midwest Tuesday 
night or early Wednesday. Expect widespread rain as the front moves 
across the area Tuesday night. Canadian high over the upper Midwest 
will build into the region and should be able to push the front into 
Tennessee/Arkansas by early Thursday. Cooler/drier weather is not expected to 
last long though as upper ridge is forecast to build across the 
Midwest by Saturday. 


Tps 


&& 


Aviation... 
/637 PM CDT Sat Jul 5 2008/ 
for the 00z tafs... 
primary concern for aviators tonight will be possible hazy 
conditions much like last night. Current observations are all 10sm 
or better...but am noticing a milky appearance to the sky on 
satellite pictures and upon direct observation outside the office. 
However...the lower atmosphere did mix pretty well so I am not 
very confident that we'll see visibilities drop as low as MVFR like last 
night. The milky appearance on satellite is confined to Illinois 
and parts of eastern Missouri within about 40 miles of the 
Mississippi. If lower visibilities in haze do develop...I expect that the 
MVFR conditions will be confined to those areas. Elsewhere and 
otherwise...daytime cumulus will dissipate after sunset. Could see 
some 5-7000ft clouds develop after 08z...especially over central 
Missouri...and surface flow will slowly become southerly on Sunday morning. 


Carney 


&& 


Lsx watches/warnings/advisories... 
MO...none. 
Illinois...none. 
&& 


$$ 


Weather forecast office lsx