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Area forecast discussion...updated aviation 
National Weather Service St Louis MO 
629 am CDT Monday Oct 6 2008 


Discussion... 
/346 am CDT Monday Oct 6 2008/ 
deep trough digging across Southern Plains this morning will bring the next chance 
of precipitation to the area tonight. Short wave rounding the base of the trough has 
produced a line of convection from Kansas southward to southern Texas. All the models seem 
to have a gd handle on what is going on now. However...solutions vary 
even as early as mid-day. The opr GFS seems to be the outlier... 
progressing the system much faster than the other models. Have 
trended forecast toward the sref...NAM Canadian and European model (ecmwf). 


Expect convection to enter western portions of the County Warning Area after midnight tonight. 
Precipitation should refocus further S on Tuesday as surface low develops. NAM 
solution suggests a different mass field. However...European model (ecmwf) and gefs 
mean would also suggest better forcing further S. Have therefore 
concentrated higher probability of precipitation for southern portions of the County Warning Area. 


Precipitation should pull out of the County Warning Area on Wednesday. Have kept some chance probability of precipitation 
going to account for the system slowing down. Have left remainder 
of the forecast dry. 


Temperatures for today have been difficult. Cloud cover today across cntl MO may 
keep temperatures in low 80s...possibly even lower. However...since all MOS 
guidance is nearly identical...have a hard time going with 
different values. Tomorrow and Wednesday should be cooler before winds become more 
southerly and start a wrmng trend on Thursday. Have trended forecast toward cooler 
temperatures. Believe GFS underestimates the strength of the surface ridge 
and brings next system in too fast. 


Tilly 


&& 


Aviation... 
/620 am CDT Monday Oct 6 2008/ 
for the 12z tafs... 
some patchy fog in the Missouri River bottoms has been impacting 
ksus on and off during the overnight hours. This will continue to 
be a possibility through 14z. Otherwise VFR conditions to prevail at 
all taf sites through at least middle evening with just an increase 
in high clouds and then middle clouds. Clouds will increase and 
thicken later tonight as the storm system in the plains slowly 
moves eatward...also spreading a shield of precipitation into portions of 
central and southeast MO. I introduced rain showers into the forecast at kcou 
late tonight. Could have some thunder as well but confidence in 
this weather type is low at this time. 


Glass 


&& 


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


$$ 


Weather forecast office lsx