Alert archive / Illinois / Flash Flood Warnings in 2026
Flash Flood Warning 66, NWS Lincoln, IL
NWS Lincoln, IL issued this flash flood warning at Aug 15, 2026, 2:19 AM CDT for McLean County, Illinois. It was in force for 5 hr. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 15, 2026, 2:19 AM CDT (07:19 UTC)
- Expired
- Aug 15, 2026, 7:40 AM CDT
- In force
- 5 hr
- Issued by
- NWS Lincoln, IL
- Area
- Storm-based polygon
- Flood severity
- None
County McLean County, IL
The radar
The Lincoln radar (KILX), 74 km from the middle of the area, began a volume at 07:22 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 15, 7:00 AM CDT | RAIN 2.84 | 3 Ne Bellflower, IL | Cocorahs station IL-MCL-30 Saybrook 4.3 SSE. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 7.3 hours before the alert went out and 31 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1237 J/kg
- Mixed-layer CIN
- -137 J/kg
- Mixed-layer LCL
- 748 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 167 m²/s²
- 0-3 km storm-relative helicity
- 197 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.2
The text
As transmitted.
572
WGUS53 KILX 150719
FFWILX
ILC113-151030-
/O.NEW.KILX.FF.W.0066.260815T0719Z-260815T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Lincoln IL
219 AM CDT Sat Aug 15 2026
The National Weather Service in Lincoln has issued a
* Flash Flood Warning for...
Southeastern McLean County in central Illinois...
* Until 530 AM CDT.
* At 218 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts up to 1 inch are possible
in the warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban
areas, highways, streets and underpasses as well as
other poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Colfax, Saybrook, Bellflower, Arrowsmith, Cropsey and Anchor.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4062 8855 4062 8852 4062 8846 4028 8846
4028 8848 4028 8852 4028 8854 4028 8855
4028 8858 4028 8860 4028 8865 4062 8863
4062 8856
FLASH FLOOD...RADAR INDICATED
$$
MJA2 follow-up statements
482
WGUS53 KILX 150835
FFWILX
ILC113-151300-
/O.EXT.KILX.FF.W.0066.000000T0000Z-260815T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Lincoln IL
335 AM CDT Sat Aug 15 2026
The National Weather Service in Lincoln has extended the
* Flash Flood Warning for...
Southeastern McLean County in central Illinois...
* Until 800 AM CDT.
* At 335 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts up to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban
areas, highways, streets and underpasses as well as
other poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Colfax, Saybrook, Bellflower, Arrowsmith, Cropsey and Anchor.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4062 8855 4062 8852 4062 8846 4028 8846
4028 8848 4028 8852 4028 8854 4028 8855
4028 8858 4028 8860 4028 8865 4062 8863
4062 8856
FLASH FLOOD...RADAR INDICATED
$$
Copple204
WGUS73 KILX 151240
FFSILX
Flash Flood Statement
National Weather Service Lincoln IL
740 AM CDT Sat Aug 15 2026
ILC113-151250-
/O.CAN.KILX.FF.W.0066.000000T0000Z-260815T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
McLean IL-
740 AM CDT Sat Aug 15 2026
...FLASH FLOOD WARNING FOR SOUTHEASTERN MCLEAN COUNTY HAS BEEN
REPLACED WITH A FLOOD WARNING...
&&
LAT...LON 4062 8855 4062 8852 4062 8846 4028 8846
4028 8848 4028 8852 4028 8854 4028 8855
4028 8858 4028 8860 4028 8865 4062 8863
4062 8856
$$
MJAWhat forecasters said that day
The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Lincoln, IL wrote its last area forecast discussion before this flash flood warning went out at Aug 15, 12:23 AM CDT, 1 hour 56 minutes earlier. Its key messages:
- There is a significant threat of flash flooding across portions of central Illinois overnight into early Saturday morning, where thunderstorms track over areas that have already seen 4-6 inches of rain since Thursday. Areas north of a Havana to Bloomington line are most at risk.
- Some of these storms also have the potential to produce damaging winds, mainly after midnight.
- The heat and humidity remain a concern for the weekend, with the highest chances of seeing more than a 105 degree heat index (40-60%) in areas from Beardstown southeast to Marshall.
Area forecast discussion, Aug 15, 12:23 AM CDT, 1 hour 56 minutes before
Area Forecast Discussion National Weather Service Lincoln IL 1223 AM CDT Sat Aug 15 2026 .KEY MESSAGES... - There is a significant threat of flash flooding across portions of central Illinois overnight into early Saturday morning, where thunderstorms track over areas that have already seen 4-6 inches of rain since Thursday. Areas north of a Havana to Bloomington line are most at risk. - Some of these storms also have the potential to produce damaging winds, mainly after midnight. - The heat and humidity remain a concern for the weekend, with the highest chances of seeing more than a 105 degree heat index (40-60%) in areas from Beardstown southeast to Marshall. && .DISCUSSION... Issued at 231 PM CDT Fri Aug 14 2026 The busy weather trend continues, and focus efforts has primarily been with the first 24-36 hours of the forecast. Flooding Concerns: The earlier rainfall has finally moved out, and the Flood Watch for east central Illinois was cancelled. Rainfall amounts of 4 to 6 inches were fairly widespread from the I-74 corridor and then southward in east central Illinois to I-70. While the earlier watch from Havana-Bloomington northward was allowed to expire at 10 am, a new watch has been issued for this area beginning at 10 pm tonight. The next MCS is expected to develop across Iowa this evening, as an upper wave moves across that area, and then move into Illinois shortly after midnight. HREF precipitable water values over 2.2 inches remain in place overnight across the northern third of Illinois, and probabilities of over 2 inches of rain tonight are highest from Galesburg to Lacon (40-60%). However, its LPMM guidance suggests 3-5 inches are a valid concern, depending on where exactly the MCS tracks. While the flooding is the main focus with this MCS, there remains a level 2 severe weather threat with it, primarily for scattered damaging winds. Heat Concerns: Extensive rain today has significantly kept temperatures lower than earlier projections. While skies are now becoming partly sunny south of I-72, it is unclear whether enough sunshine will get heat index readings up to 100 degrees in any of the advisory area today. The current advisory area is expected to have less impact from the overnight MCS, and guidance continues to point toward heat index values 105-110 degrees on Saturday and Sunday. No changes in the Heat Advisory were made in that area for this reason. Further north, NBM guidance is also showing similar heat index for Saturday for all of central Illinois. However, the lingering effects of the next MCS suggest the guidance is overdoing projections. HREF probabilities of greater than 105 degree heat index on Saturday are highest from Beardstown southeast through Taylorville to Marshall (40-60%), and tail off pretty quickly north of there. Will leave any headline changes for the overnight forecast cycle, once the MCS shows its hand. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1223 AM CDT Sat Aug 15 2026 Thunderstorms are moving across portions of central Illinois during the early overnight hours and expected to continue into Saturday morning before exiting east of the area. MVFR/IFR ceilings currently in place north of the terminals will sink south to along the I-74 corridor overnight, but confidence is currently low that it will reach as far south as SPI/DEC. Areas that do drop are expected to improve back to VFR early to mid Saturday afternoon as winds veer to SWerly. && .ILX WATCHES/WARNINGS/ADVISORIES... Flood Watch until 10 AM CDT this morning for ILZ027>031- 036>038-040-041-043>046-055-057. Heat Advisory until 8 PM CDT Sunday for ILZ049>052-061>063- 066>068-071>073. && KEY MESSAGES...Geelhart DISCUSSION...Geelhart AVIATION...Deubelbeiss
Hazardous weather outlook, Aug 14, 3:00 PM CDT, 11 hours 19 minutes before
Hazardous Weather Outlook National Weather Service Lincoln IL 300 PM CDT Fri Aug 14 2026 ILZ027>031-036>038-040>057-061>063-066>068-071>073-151100- Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean-Schuyler- Mason-Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard-Scott- Morgan-Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar-Shelby- Cumberland-Clark-Effingham-Jasper-Crawford-Clay-Richland-Lawrence- 300 PM CDT Fri Aug 14 2026 This Hazardous Weather Outlook is for central Illinois, east central Illinois, southeast Illinois and west central Illinois. .DAY ONE...Tonight. Widespread thunderstorm activity is likely tonight, mainly north of I-72. Locally strong to severe storms and flash flooding are possible. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. Hot and humid conditions will peak over the area this weekend. Peak afternoon heat indices will range from 103 to 112 Saturday, and 100 to 105 Sunday. Daily chances for thunderstorms exist through the weekend, mainly north of I-70 for Saturday. Some of these storms could be severe and produce heavy rain. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed after midnight. 37
In the hours before
Local storm report, Aug 15, 1:38 AM CDT, 41 minutes before
Preliminary Local Storm Report
National Weather Service Lincoln IL
138 AM CDT Sat Aug 15 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0135 AM Flash Flood Bloomington 40.48N 88.99W
08/15/2026 McLean IL Public
Several flooded roads reported on Douglas
Street and viaducts underwater, relayed by
broadcast media from viewer.
0135 AM Flash Flood 1 W Normal 40.51N 89.00W
08/15/2026 McLean IL Public
Adelaide and Bryan streets in Bloomington
are impassible and underwater, relayed by
broadcast media from viewer.
&&Local storm report, Aug 15, 1:46 AM CDT, 33 minutes before
Preliminary Local Storm Report
National Weather Service Lincoln IL
146 AM CDT Sat Aug 15 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0144 AM Flash Flood Tremont 40.53N 89.49W
08/15/2026 Tazewell IL Public
6 inches of water flowing over E Pearl
Street.
&&
RACLocal storm report, Aug 15, 2:12 AM CDT, 7 minutes before
Preliminary Local Storm Report
National Weather Service Lincoln IL
212 AM CDT Sat Aug 15 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0209 AM Flash Flood 3 WNW Mackinaw 40.56N 89.40W
08/15/2026 Tazewell IL Public
Allentown Road about a mile west of
Allentown is flooded over.
&&
RACThe office that day
Everything else NWS Lincoln, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 14, 11:56 PM CDT | Flash Flood Warning | ILX | Fulton, Knox, Mason, Peoria, Tazewell, Woodford | 7 hr |
| Aug 15, 1:09 AM CDT | Flash Flood Warning | ILX | McLean | 6 hr |
| Aug 15, 1:23 AM CDT | Severe Thunderstorm Warning | ILX | Fulton, Mason | 67 min |
| Aug 15, 1:51 AM CDT | Severe Thunderstorm Warning | ILX | Fulton | 24 min |
| Aug 15, 2:23 AM CDT | Severe Thunderstorm Warning | ILX | Peoria, Tazewell | 38 min |
| Aug 15, 2:36 AM CDT | Flash Flood Warning | ILX | McLean | 6 hr |
| Aug 15, 3:23 AM CDT | Flash Flood Warning | ILX | Champaign | 5 hr |
| Aug 15, 3:43 AM CDT | Severe Thunderstorm Warning | ILX | Cass, Fulton, Mason, Menard, Morgan, Schuyler and 1 more | 62 min |
| Aug 15, 3:54 AM CDT | Flash Flood Warning | ILX | Vermilion | 4 hr |
| Aug 15, 4:29 AM CDT | Special Weather Statement | ILX | Logan, Menard, Sangamon | 31 min |
| Aug 15, 5:33 AM CDT | Areal Flood Advisory | ILX | Morgan | 3 hr |
| Aug 15, 5:48 AM CDT | Flash Flood Warning | ILX | Champaign, Vermilion | 8 hr |
| Aug 15, 6:24 AM CDT | Special Weather Statement | ILX | Champaign, Piatt, Vermilion | 36 min |
| Aug 15, 6:37 AM CDT | Areal Flood Warning | ILX | Fulton, Knox, Mason, Peoria, Tazewell, Woodford | 27 hr |
| Aug 15, 7:33 AM CDT | Areal Flood Warning | ILX | McLean | 65 min |
| Aug 15, 7:40 AM CDT | Areal Flood Warning | ILX | McLean | 26 hr |
| Aug 15, 8:04 AM CDT | Flash Flood Warning | ILX | McLean | 5 hr |
| Aug 15, 8:38 AM CDT | Flash Flood Warning | ILX | McLean | 4 hr |
| Aug 15, 10:11 AM CDT | River Flood Warning | ILX | Cass, Fulton, Mason | 13 days |
| Aug 15, 10:12 AM CDT | River Flood Warning | ILX | Brown, Cass, Morgan, Schuyler | 14 days |
| Aug 15, 10:19 AM CDT | River Flood Warning | ILX | Piatt | 7 days |
| Aug 15, 12:40 PM CDT | Areal Flood Warning | ILX | McLean | 21 hr |
| Aug 15, 1:40 PM CDT | Areal Flood Warning | ILX | Champaign, Vermilion | 46 hr |
| Aug 15, 1:46 PM CDT | River Flood Warning | ILX | McLean, Tazewell, Woodford | 20 hr |
Nearby
Flash Flood Warnings in Illinois, 2026Every flash flood warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.