574 
fxus63 kilx 292000 
afdilx 


Area forecast discussion 
National Weather Service Lincoln Illinois 
300 PM CDT Friday Aug 29 2008 


Discussion... 
issued 300 PM CDT Friday Aug 29 2008 


Short term...tonight through Monday... 
dry weather expected through Monday so the short term will be mainly 
a temperature forecast. Large surface high now extends from southern 
Nebraska into Wisconsin...and will move to the Great Lakes where it 
will sit into early next week. At the same time...an upper ridge 
will also build into the region with 500mb heights of 591 dm or more 
by the end of Sunday. Therefore temperatures should warm day-to-day 
despite weak thermal advection. Expect highs in the low to middle 80s 
Saturday will warm into the upper 80s/lower 90s by Monday. 


Long term...Tuesday through Friday... 
Tuesday and Wednesday will remain dry with the surface high only 
slowly moving out of the Great Lakes. The longer range models then 
begin to shift the western Continental U.S. Upper trough into the northern 
plains by late Wednesday with the flow becoming increasingly flat 
toward the end of next week. Bulk of the forecast for Thursday and 
Friday rests with the evolution of Gustav...and whether its tropical 
moisture will get picked up by the northern plains trough and flow 
northward. Still way too early to predict where Gustav will be and 
how fast it will move...so will go with slowly increasing probability of precipitation 
Thursday and Friday. Much can change that far in advance when there 
are tropical systems involved...so forecast confidence by the end of 
the period is lower than normal. 


04 
&& 


Aviation... 
issued 1237 PM CDT Friday Aug 29 2008 


Light northerly flow is noted across the taf sites early this 
afternoon in the wake of a weak cold front now in the Ohio Valley. 
Drier airmass is slowly filtering southward into the area...with 
satellite showing clear skies across the northern terminals. 
Meanwhile...enough residual low-level moisture remains along and 
south of I-72 to produce scattered-broken cloud cover at the remaining sites. 
General trend will be for a reduction in cloud cover as the afternoon 
progresses...so will only carry sct040 at kspi...kdec...and kcmi. 
Skies clear out across the board after 00z and winds become light 
and variable. With drier airmass in place overnight...do not think 
fog will be an issue. After that...clear skies and light east/NE flow 
will be noted Saturday morning. 


Barnes 
&& 


Ilx watches/warnings/advisories... 
none. 
&& 


$$