Area Forecast Discussion
Issued by NWS Central Illinois

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019
FXUS63 KILX 310450
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1150 PM CDT Sat May 30 2026

.KEY MESSAGES...

- Above normal temperatures are likely to persist into mid June,
  with highs likely in the 80s over the next two weeks.

- There is a 20-30% chance of showers and thunderstorms over
  west central IL from Galesburg to Springfield west into early
  evening. There is a 30-50% chance for showers and
  thunderstorms storms from Peoria to Lawrenceville west
  overnight Sunday night into Monday, with chances highest
  southwest of Springfield.

&&

.DISCUSSION...
Issued at 230 PM CDT Sat May 30 2026

The 19Z/2 pm surface analysis shows 1029 mb high pressure over
James Bay Canada and ridging southward across the Great Lakes
and into the Ohio river valley. Easterly flow of drier air over
central and eastern IL with dewpoints in the upper 40s to mid
50s, while higher dewpoints in the upper 50s/lower 60s from
Jacksonville to Taylorville to Effingham and Olney sw. Warm
temps were in the low to mid 80s at 2 pm. Radar mosaic shows a
narrow bands of showers west of a Monmouth to Havana to
Jacksonville line drifting northward. Scattered showers and
thunderstorms were over MO and into the St Louis metro area.
More unstable air mass was over sw IL/MS river valley where
MLCAPES are 500-1500 j/kg and PW values are 1.7-1.9 inches. We
added 20-30% chances of showers and isolated thunderstorms into
early evening along and west of a Galesburg to Springfield line.
The isolated convection over west central IL should dissipate by
dusk. Latest CAMs shows more convection developing over MO
tonight and weakening as it drifts into west central IL later
tonight into Sunday morning where air mass is more stable. Lows
overnight 55-60F, coolest in east central IL. A bit cooler highs
Sunday in the upper 70s/lower 80s with partly to mostly cloudy
skies.

Convection chances to increase overnight Sunday night over
central and west central IL with increase moisture spreading a
bit further east into IL. Have 20-40% chance of convection
lingering over central/sw CWA Monday. SPC Day3 has a marginal
risk of severe storms Monday sw of a Macomb to Springfield to
Flora line for damaging winds and hail being risks. Though more
unstable air mass will remain over MO where better chance of
storms will be. Highs Monday mostly in the lower 80s.

Another Canadian high pressure system drops down into the Great
Lakes region from Hudson Bay on Mon night and Tue and into the
southern Great Lakes, ohio river valley on Wed. This to bring
drier more stable air back into central IL with dry weather
during mid week. As large high pressure sprawls across the mid
Atlantic States on Thursday will see SSW flow begin and start
to bring warmer air back into the area, along with more
humidity too especially Fri/Sat with dewpoints back into the
60s. This will return chances of convection to central IL Friday
and central and southeast IL Fri night/Saturday.

The Climate Prediction Center (CPC) 8-14 Day Outlook for June
7-13th has 45-55% chance of above normal temperatures over
central/se IL with precipitation trending near normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1150 PM CDT Sat May 30 2026

Another set of VFR TAFs as dry easterly low level flow remains
in place. An area of -SHRA/TSRA to our west is forecast to move
into west central IL later this morning, then turn south. Kept
KPIA-KSPI dry for now but will monitor trends as the area of
convection develops. E-SE winds will persist near/under 10 kt
through the forecast.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

KEY MESSAGES...07
DISCUSSION...07
AVIATION...25