Severe Thunderstorm Warning 172, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
639 PM CDT Mon Apr 27 2026

.KEY MESSAGES...

- There is a level 3 of 5 (enhanced) risk for severe weather this
  evening. Damaging winds, large hail, a couple tornadoes, and
  flash flooding are all concerns, especially near and south of
  I-70.

- There is a 30-50% chance for frost Friday night. Tender
  vegetation may need to be covered in order to prevent damage.

&&

.DISCUSSION...
Issued at 226 PM CDT Mon Apr 27 2026

***** SEVERE WEATHER THIS EVENING *****

Mid level water vapor satellite reveals a negatively tilted upper
level trough spinning over the Midwest. At the surface, WPC has
analyzed a 996mb low in eastern Iowa which is forecast to lift
northeastward across Wisconsin this evening. Much of the warm sector
has been worked over at this point via a morning-early afternoon
MCS, but these storms left an outflow boundary near/south of the I-
70 corridor which will serve as a differential heating/convergence
zone for renewed storms later this afternoon. A wake low continues
to foster wind gusts up to 35mph from the southeast, which should
help maintain stable low levels further north. Nonetheless, a few
elevated storms could generate locally severe hail and wind in
those areas. Meanwhile, south of the I-70 corridor, dewpoints
should surge into the mid-upper 60s while a 50 kt LLJ maintains
40-55 kt effective bulk wind shear and 400-700 (679 on the VWX
vad profiler) m^2/s^2 0-3km SRH via strongly cyclonically
curved hodographs. CAMs generally suggest convective activity
developing upstream over the next couple hours and moving
through this environment during the evening will start discrete
and eventually grow upscale into another MCS. Hence, the initial
hazards will be very large hail and tornadoes, with the risk
transitioning to damaging winds, locally severe hail, and QLCS
tornadoes with time. Training storms will pose a risk for flash
flooding (REFS and HREF ensemble max precip have swaths of 4+
inches of rain falling in <6 hours), for which we have issued a
Flood Watch which extends through 10pm. A Tornado Watch is in
effect for Effingham to Crawford Counties and areas further
south, where the chance of surface based (and hence potentially
tornadic) storms is highest. Storms should exit the ILX County
Warning area by 11pm, while a cooler and more stable airmass
arrives from the west-northwest behind a cold front.

***** DRY CONDITIONS LIKELY WEDNESDAY AND BEYOND  *****

Another shortwave will lift northeast through the area tomorrow
night, bringing another opportunity for some rain and perhaps a
rumble of thunder. Thankfully QPF with this system is lighter, with
a low (<20%) chance for an additional inch of rainfall. Since this
will occur around 24 hours after this evening's heavy rainfall in
southeast Illinois, the ground may have some time to absorb the
water, though we'll still be keeping one eye on it.

By Wednesday morning, a drier pattern should take hold of the
region, with less than a 20% chance for rain through the weekend.
High temperatures each day are forecast in the 60s, with locations
near and north of the I-74 corridor potentially (60% chance) not
climbing out of the 50s on Friday. The National Blend of Models
(NBM) indicates a 30-50% chance temperatures fall below 37 degF
Friday night into Saturday morning, which should be cold enough for
frost given the expected light winds.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 640 PM CDT Mon Apr 27 2026

A squall line consisting of strong to severe thunderstorms was
along I-55 at 640 pm with a severe cell ahead of this line
between DEC and CMI and racing eastward at 50-60 mph.
Convection was also over PIA which was on the back side of this
complex. We have gradient SE winds 25-35 kts with gusts 40-50
kts ahead of this squall line especially at DEC and CMI. A
severe storm would produce wind gusts over 50 kts possible at
DEC and CMI next hour. IFR to MVF conditions expected with this
strong to severe convection as HRRR has it tracking east of DEC
and CMI between 01-02Z at mid evening. May see a brief period
of VFR conditions late evening/early overnight before MVFR
ceilings likely spread into central IL during overnight and
linger into Tue morning. the MVFR ceilings could scatter out at
PIA and possibly as far se as I-55 at BMI and SPI during Tue
afternoon. Breezy south to SE winds gusting 25-35 kts to weaken
and shift west to WNW behind cold frontal passage overnight.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM CDT this evening for ILZ052>057-
061>063-066>068-071>073.

&&

KEY MESSAGES...Bumgardner
DISCUSSION...Bumgardner
AVIATION...07

Hazardous Weather Outlook
National Weather Service Lincoln IL
232 PM CDT Mon Apr 27 2026

ILZ027>031-036>038-040-041-281945-
Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean-Schuyler-
Mason-
232 PM CDT Mon Apr 27 2026

This Hazardous Weather Outlook is for central Illinois and west
central Illinois.

.DAY ONE...Tonight.

Thunderstorm redevelopment continues to be possible this afternoon
and moving east through mid evening. The storms will be capable of
producing damaging winds, hail, and a few tornadoes. In addition,
heavy rainfall may produce areas of flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Minor flooding will persist on the Illinois River from Havana to
Beardstown through the week, with some renewed rises around midweek.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

Expected storm motion is toward the east-northeast around 50 mph.

ILZ042>057-061>063-281945-
Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard-Scott-Morgan-
Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar-Shelby-
Cumberland-Clark-
232 PM CDT Mon Apr 27 2026

This Hazardous Weather Outlook is for central Illinois, east
central Illinois and west central Illinois.

.DAY ONE...Tonight.

Thunderstorm redevelopment is possible this afternoon with storms
moving out of east central Illinois by late evening. The storms will
be capable of producing damaging winds, hail, and a few tornadoes.
In addition, heavy rainfall may produce areas of flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

A few thunderstorms are expected Tuesday night, but severe weather
is not likely.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

Expected storm motion is toward the east-northeast around 50 mph.

ILZ066>068-071>073-281945-
Effingham-Jasper-Crawford-Clay-Richland-Lawrence-
232 PM CDT Mon Apr 27 2026

This Hazardous Weather Outlook is for southeast Illinois.

.DAY ONE...Tonight.

Periods of thunderstorms are expected through the evening hours.
Some of these will be severe. Damaging winds and tornadoes are the
main concerns. In addition, heavy rainfall may produce areas of
flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Scattered thunderstorms are expected Tuesday night, but severe
weather is not likely.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed.

Expected storm motion is toward the east-northeast around 50 mph.

Knutsvig

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Preliminary Local Storm Report
National Weather Service Lincoln IL
646 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0639 PM     Tstm Wnd Gst     Latham                  39.97N 89.16W
04/27/2026  E80 MPH          Logan              IL   Fire Dept/Rescue

            Estimated 70-80 mph winds.

&&

JLA

Preliminary Local Storm Report
National Weather Service Lincoln IL
647 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0643 PM     Tstm Wnd Gst     3 W Warrensburg         39.94N 89.11W
04/27/2026  E80 MPH          Macon              IL   Law Enforcement

&&

JLA

Preliminary Local Storm Report
National Weather Service Lincoln IL
650 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0610 PM     Tstm Wnd Gst     Ogden                   40.11N 87.96W
04/27/2026  M64 MPH          Champaign          IL   CO-OP Observer

&&

JLA

Preliminary Local Storm Report
National Weather Service Lincoln IL
652 PM CDT Mon Apr 27 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0645 PM     Tstm Wnd Dmg     Alvin                   40.31N 87.61W
04/27/2026                   Vermilion          IL   Emergency Mngr

            Tree down across south bound lane of State
            119.

&&

JLA