Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 270439

Area Forecast Discussion
National Weather Service Lincoln IL
1139 PM CDT TUE APR 26 2016

Issued at 905 PM CDT Tue Apr 26 2016

The initial wave of showers and storms have departed into Indiana
by 9 pm. A stationary front remains stalled across south-central
IL, roughly just north of I-70. The latest HRRR and RAP updates
show that a return of showers and scattered storms looks to hold
off until later tonight for areas W-SW of Galesburg to Springfield
to Effingham. Areas east of there have a decent chance of
remaining dry until during the day on Wed. Have updated the precip
chances to remove rain the rest of the evening, and slow down the
advance of showers after midnight. However, may still be over-done
with PoPs. Temps look on track to remain relatively stable the
rest of the night under an initial blanket of cirrus, and
eventually thickening mid clouds.

We are still expecting the showers and storms that develop
tomorrow afternoon could become severe for areas SW of Springfield
to Effingham, where SPC has defined a Slight Risk of severe

Update forecast info is already available.


.SHORT TERM...(Tonight)
ISSUED AT 243 PM CDT Tue Apr 26 2016

A cold front near I-72 will accelerate southward across southeast IL
by early this evening. Large MCS over central/ne MO and western IL
(west of PIA and SPI) will spread widespread showers and scattered
thunderstorms eastward across central and east central/southeast
IL rest of this afternoon and then diminish and past east into IN
by early evening. Strongest part of line is a bow echo moving
toward St Louis metro and areas south, and to track eastward
across southern IL. Severe thunderstorm watch til 7 pm for Scott,
Morgan, Sangamon, Christian, Shelby, Effingham and Clay counties.
Isolated to scattered showers/thunderstorms recently develop ahead
of MCS in moderately unstable warm sector south of I-72 with
Capes 2000-2600 J/kg. Bulk shear is 30-38 kts so a few of these
thunderstorms could become strong to even severe with damaging
winds and large hail. Brunt of CWA should be dry by mid evening,
but this will be short lived. 999 mb surface low pressure over
central KS to deepen to 993 mb as it moves into southeast Nebraska
by Wed morning and pulls frontal boundary back northeast toward
southwest IL. Showers and scattered thunderstorms to spread ne
into central and southeast IL overnight especially late tonight
into Wed. Lows tonight range from around 50F from Peoria and
Bloomington north to around 60F in southeast IL from I-70 south.

.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 243 PM CDT Tue Apr 26 2016

Energy rounding base of upper-level low centered over central
Rockies will be our next weather maker starting early Wednesday.
While this system will bring periods of showers/storms to the area
into Thursday, the severe threat should stay south of the area given
mainly sub 1000 j/kg CAPE values, and modest bulk shear values (30-
35 kts).

A lull in the rainfall threat is anticipated later Thursday into
Friday as Wednesday`s system departs, and as southwestern U.S.
troffing reloads. The next in our recent series of disturbances will
arrive for the weekend, along with a renewed threat of
showers/storms. While there are still differences in the details of
the weekend system, it is still looking wet overall. The slow moving
weekend system will depart by early next week, bringing another lull
in the rainfall.

Temperatures will trend downward heading into midweek, but still
hang near seasonal normals. So, it appears we have seen the last of
the 80 degree highs for at least a week or two.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1139 PM CDT Tue Apr 26 2016

A break in the showers and thunderstorms will continue through
10-12z for the most part, with SPI having the best chance of
seeing precip arrive before sunrise. HRRR and RAP keep a majority
of the area dry until after 12z, with a band of rain advancing
into central IL from the SW just after 12z. The RAP keeps precip
SW of PIA to SPI to DEC until afternoon, while the NAM12 pushes a
band of showers/storms across our terminals between 15z and 21z,
then develops a strong to severe complex of storms just west of
PIA to SPI around 00z/7pm and pushes that system across all of the
TAF sites between 01z-07z Wed night at the end of this TAF period.
Will trend toward NAM for this TAF update, but with the potential
for significant breaks in rain/storms during the day tomorrow. Will
introduce stronger storms for the evening period.

IFR clouds and MVFR VIS have already pushed southwest over BMI,
with MVFR clouds reaching PIA. HRRR projections show all TAF sites
will drop to at least MVFR with IFR likely lingering at BMI until
14-15z when MVFR conditions develop in turbulent mixing with
precip onset. Will keep MVFR conditions as prevailing for a
majority of the next 24 hours, with tempos for IFR or LIFR
tomorrow eve with strongest storms.

Breezy northeast winds tonight near 15-17 kts are expected to veer
more east to southeast by Wed afternoon and gust to 18-24 kts, as
a warm front lifts north into central IL.


.ILX Watches/Warnings/Advisories...


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