Alert archive / Minnesota / Red Flag Warnings in 2025

Red Flag Warning 4, NWS Duluth, MN

May 20, 20255 counties in Minnesota

NWS Duluth, MN issued this red flag warning at May 20, 2025, 3:18 AM CDT for 5 counties in Minnesota. It took effect at May 20, 2025, 12:00 PM CDT. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 20, 2025, 3:18 AM CDT (08:18 UTC)
In effect from: May 20, 2025, 12:00 PM CDT
Expired: May 20, 2025, 9:00 PM CDT
In force: 9 hr
Issued by: NWS Duluth, MN

Counties Cook County, MN, Itasca County, MN, Koochiching County, MN, Lake County, MN, Saint Louis County, MN

The radar

The Duluth radar (KDLH), 101 km from the middle of the area, began a volume at 08:21 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.

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 8.3 hours before the alert went out and 116 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2431 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: -37 m²/s²
0-3 km storm-relative helicity: 123 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Duluth, MN wrote its last area forecast discussion before this red flag warning went out at May 20, 1:08 AM CDT, 2 hours 10 minutes earlier.

Area forecast discussion, May 20, 1:08 AM CDT, 2 hours 10 minutes before

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Hazardous weather outlook, May 19, 6:37 PM CDT, 8 hours 41 minutes before

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In the hours before

Local storm report, May 20, 12:04 AM CDT, 3 hours 14 minutes before

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Local storm report, May 20, 12:14 AM CDT, 3 hours 4 minutes before

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Special weather statement, May 20, 3:18 AM CDT, 0 minutes before

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The office that day

Everything else NWS Duluth, MN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 9:59 AM CDT	High Wind Warning	DLH	Carlton, Saint Louis	8 hr
May 20, 10:04 AM CDT	Storm Warning	DLH		8 hr

Nearby

Red Flag Warnings in Minnesota, 2025 Every red flag warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.