Flash Flood Warning Issued for Northeastern Mercer County, IL

Source: NOAA · Mercer County, Illinois

This alert is no longer in effect.

NOAA issued it on August 19, 2026, 4 days ago. Warnings of this kind stay in effect for hours to a few days, so this page is a historical record of what was issued, not a current warning. For conditions where you are right now, check weather.gov (US), weather.gc.ca (Canada), the Met Office (UK), or the Bureau of Meteorology (Australia).

Areazine synthesizes this NWS weather alert directly from NOAA's official public data feed. See our methodology for full source attribution and refresh cadence.

NWS Quad Cities has issued a Flash Flood Warning for northeastern Mercer County in northwestern Illinois until midnight CDT due to heavy rain from thunderstorms.

Read this weather record in 30 seconds

Record type
Flash Flood Warning
Affected area
Mercer County, Illinois
Issued
August 19, 2026
Issuing authority
NWS Quad Cities IA IL

Flood notices turn on location and timing. Treat the named area as this record's scope; do not assume nearby counties, parishes, or waterways were included.

Record status: historical. It was issued 4 days ago; use the issuing agency's live warning service for current conditions in Mercer County, Illinois.

Alert Details

A Flash Flood Warning has been issued by the National Weather Service in Quad Cities IA IL. The alert is effective from August 19 at 6:06 PM CDT until August 20 at 12:00 AM CDT.

Affected Areas

Northeastern Mercer County in northwestern Illinois, including Viola, New Windsor, Matherville, Boden, Shale City, Griffin, Gilchrist, Wanlock and Old Gilchrist.

What You Should Do

Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.

Expected Conditions

Doppler radar indicated thunderstorms producing heavy rain across the warned area. Between 1 and 2 inches of rain have fallen, with additional rainfall amounts of 1 to 2 inches possible.

Timeline

The warning is in effect from 6:06 PM CDT on August 19 until midnight CDT on August 20. Flash flooding is ongoing or expected to begin shortly.

Original source: NOAA Official Notice ↗

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Nationwide notices with similar length or severity timing 8

Two Areazine-derived peer sets for this NWS weather alert: nearest notices by body length and by same severity near the same agency date. Peers come from other categories so they are not the same-feed Related list above.

Frequently Asked Questions

Common questions about this NWS weather alert.

What is this NWS weather alert about?
NWS Quad Cities has issued a Flash Flood Warning for northeastern Mercer County in northwestern Illinois until midnight CDT due to heavy rain from thunderstorms.
Which agency issued this alert?
This alert was issued by NOAA. The original notice is available at the source link at the bottom of this article.
How severe is this alert?
This alert is classified as "high" severity. Take precautions and monitor for updates.
What area is affected?
This alert affects Mercer County, Illinois. Check with NOAA for the most current geographic scope.
Where can I find more Weather Alerts updates?
Browse the full Weather Alerts feed on Areazine at areazine.com/weather/ for the latest updates from NOAA and other agencies.