108 
fxus63 kilx 191509 
afdilx 


Area forecast discussion 
National Weather Service Lincoln Illinois 
1009 am CDT Friday Mar 19 2010 


Discussion... 
issued 1009 am CDT Friday Mar 19 2010 


High pressure anchored over the Tennessee River valley continues 
to provide central Illinois with a warm S/SW flow. Despite quite a 
bit of high cloudiness streaming across the area...15z temperatures have 
risen well into the 50s. Strong cold front currently pushing into 
eastern Iowa will arrive in the Illinois River valley by late this 
afternoon...however any significant cloud cover or precipitation will 
hold off until after dark. Ahead of the front...partly to mostly 
sunny skies will be the rule for the remainder of the day...with 
highs ranging from the lower 60s northwest to the upper 60s south 
of I-70. Have adjusted hourly temperatures...but have made no major 
changes to the current forecast. 


Barnes 
&& 


Aviation... 
issued 652 am CDT Friday Mar 19 2010 


VFR conditions will continue next 24hrs at all taf sites. Just 
some high cirrus ahead of the cold front that is expected to move 
through all sites today or this evening. Front will move south and 
should move through pia first around 22z. Bmi will be next around 
00z followed by spi...Dec and cmi at 01...02 and 03z respectively. 
Precipitation will start in pia late while other sites will not see precipitation 
until after 12z. Southwest winds ahead of the front with wind 
transitioning to northwest...then north-northeast. Winds will also 
increase in speed. 


Auten 
&& 


Previous discussion... 
issued 220 am CDT Friday Mar 19 2010 


High clouds spreading eastward across central Illinois early this 
morning...ahead of a cold front which extends from central Upper 
Michigan...through central Iowa...into southwest Kansas. Upper 
shortwave evident on water vapor imagery from Ontario southwest 
into the Desert Southwest. These features will be dominating the 
weather in our area over the next few days. 


Short term...today through Monday... 


Another warm day expected across the County Warning Area today...with highs in the 
middle 60s...albeit with some more cloudiness than yesterday. 


Although the NAM model is a bit faster than the others in terms of 
the speed of the front itself...the models are coming into more 
of a consensus on the low pressure wave that will form along this 
front...as the south end of the upper shortwave closes off over 
Oklahoma Saturday night. 


The cold front is expected to be moving into the northwest tip of 
the County Warning Area by early evening...and should be near I-70 by late 
Saturday afternoon before it begins to stall. The bulk of the 
precipitation will be Post frontal through Saturday afternoon... 
then a brief break may occur over the southeast County Warning Area before the 
next wave of precipitation associated with the low itself. 
Forecast soundings still indicate a rain/snow mix northwest of the 
Illinois River by Saturday morning...changing to snow in the 
afternoon. Soil temperatures are currently in the 40s...which 
should help mitigate much of the potential accumulation...but an 
inch or two may accumulate by Sunday morning. The remainder of the 
County Warning Area will see rain during the day Saturday...but soundings indicate 
a mixture as far east as I-55 by midnight. A wide range in 
temperatures will occur...with 60s again likely south of I-70 
ahead of the front...and middle 30s northwest of the Illinois River 
with falling daytime temperatures. 


Main surface wave expected to lift northeast out of Arkansas 
Sunday toward the Ohio Valley. Highest probability of precipitation expected across the 
southeast half of the County Warning Area as a result. Warmer air aloft will surge 
back into the area ahead of this low...beginning late Saturday 
night. This should keep the precipitation on Sunday and Sunday 
night as mainly rain...except for a bit of a mix near Galesburg. 


The upper low should move to southeast Tennessee by midday 
Monday...with the surface wave over West Virginia. However...an 
associated surface trough will extend back into southeast 
Illinois...so have kept some slight chance probability of precipitation in that area 
through Monday morning. 


Long term...Tuesday through Thursday... 


A similar upper pattern is expected next week...as a split flow 
dominates North America and a shortwave across The Rockies in the 
southern stream. This one appears to be not as strong as the 
current wave...and will be responsible for the next rain chances 
over the area. Temperatures expected to be well above normal again 
for Tuesday and especially Wednesday. 


Geelhart 


&& 


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


$$