Alert archive / Minnesota / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 99, NWS Duluth, MN

August 7, 2020Cass County, Crow Wing County, Minnesota

NWS Duluth, MN issued this severe thunderstorm warning at Aug 7, 2020, 9:16 PM CDT for Cass County, Crow Wing County, Minnesota. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 7, 2020, 9:16 PM CDT (02:16 UTC)
Expired
Aug 7, 2020, 9:45 PM CDT
In force
29 min
Issued by
NWS Duluth, MN
Area
Storm-based polygon
Tornado
Possible
Hail
1.25 in
Wind
60.0 mph

Counties Cass County, MN, Crow Wing County, MN

The radar

The Duluth radar (KDLH), 152 km from the middle of the area, began a volume at 02:18 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 7, 3:52 PM CDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 2.3 hours before the alert went out and 213 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2020-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 933 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2020-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 160 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
933 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
1112 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.6
Supercell composite
9.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Aug 7, 6:35 PM CDT, 2 hours 41 minutes earlier.

Area forecast discussion, Aug 7, 6:35 PM CDT, 2 hours 41 minutes before
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Hazardous weather outlook, Aug 7, 11:20 AM CDT, 9 hours 56 minutes before
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In the hours before

Special weather statement, Aug 7, 7:17 PM CDT, 1 hour 59 minutes before
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Special weather statement, Aug 7, 7:48 PM CDT, 1 hour 28 minutes before
Special Weather Statement
National Weather Service Duluth MN
748 PM CDT Fri Aug 7 2020

MNZ018-025-026-080115-
North Cass-North Itasca-South Itasca-
748 PM CDT Fri Aug 7 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL ITASCA AND
NORTHERN CASS COUNTIES...

At 747 PM CDT, strong thunderstorms were along a line extending from
near Lake Winnibigoshish, to Akeley, and moving east at 30 mph.

Wind gusts up to 40 mph, dime size hail, heavy downpours, and
frequent cloud to ground lightning can be expected with these storms.

Locations impacted include...
Walker, Deer River, Longville, Bena, Federal Dam, Zemple, Boy River,
Leech Lake, Ball Club, Lake Winnibigoshish, Woman Lake, Wilkinson,
Boy Lake, Ten Mile Lake, Ball Club Lake, Portage Lake, Mud Lake, Six
Mile Lake, Brevik, and Goose Lake.

Seek shelter inside a sturdy building and away from windows until
these storms pass. Get off area lakes, including Leech Lake and seek
shelter on shore in a sturdy shelter or a hard topped vehicle.

A Severe Thunderstorm Watch remains in effect until 100 AM CDT for
north central Minnesota.

LAT...LON 4724 9466 4751 9418 4753 9343 4691 9435
      4696 9466
TIME...MOT...LOC 0047Z 266DEG 26KT 4741 9412 4700 9473

LE
Special weather statement, Aug 7, 8:19 PM CDT, 57 minutes before
Special Weather Statement
National Weather Service Duluth MN
819 PM CDT Fri Aug 7 2020

MNZ018-025-026-080145-
North Cass-North Itasca-South Itasca-
819 PM CDT Fri Aug 7 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL ITASCA AND
NORTHERN CASS COUNTIES...

At 818 PM CDT, strong thunderstorms were along a line extending from
7 miles northwest of Marcell, to Days High Landing, to 6 miles
northeast of Hackensack, and moving east at 25 mph.

Wind gusts up to 40 mph, torrential rainfall, and frequent cloud to
ground lightning can be expected with these storms.

Locations impacted include...
Grand Rapids, Walker, Cohasset, Coleraine, Deer River, Marcell,
Bigfork, Remer, Taconite, Longville, Bena, Federal Dam, Zemple, Boy
River, Leech Lake, Inger, Days High Landing, Pokegama Dam, Gunn, and
Ball Club.

Seek shelter inside a sturdy building and away from windows until
these storms pass. Get off area lakes and seek shelter on shore in a
sturdy shelter or a hard topped vehicle.

LAT...LON 4779 9340 4725 9338 4693 9420 4707 9464
      4744 9414 4771 9397
TIME...MOT...LOC 0118Z 271DEG 20KT 4766 9383 4726 9382 4702 9445

Melde
Local storm report, Aug 7, 8:55 PM CDT, 21 minutes before
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Special weather statement, Aug 7, 8:55 PM CDT, 21 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 7:17 PM CDTSpecial Weather StatementDLHCass28 min
Aug 7, 7:48 PM CDTSpecial Weather StatementDLHCass, Itasca27 min
Aug 7, 8:19 PM CDTSpecial Weather StatementDLHItasca26 min
Aug 7, 8:28 PM CDTSevere Thunderstorm WarningDLHCass62 min
Aug 7, 8:52 PM CDTTornado WarningDLHCass23 min
Aug 7, 8:55 PM CDTSpecial Weather StatementDLHItasca35 min
Aug 7, 9:29 PM CDTSevere Thunderstorm WarningDLHAitkin, Itasca, Saint Louis31 min
Aug 7, 9:55 PM CDTSpecial Weather StatementDLHCass20 min
Aug 7, 10:00 PM CDTSpecial Weather StatementDLHSaint Louis30 min
Aug 7, 10:17 PM CDTSpecial Weather StatementDLHCass28 min
Aug 7, 10:35 PM CDTSpecial Weather StatementDLHAitkin25 min
Aug 7, 10:37 PM CDTSpecial Weather StatementDLHSaint Louis23 min
Aug 7, 10:44 PM CDTSpecial Weather StatementDLHCrow Wing31 min
Aug 7, 10:58 PM CDTSpecial Weather StatementDLHAitkin32 min
Aug 7, 11:03 PM CDTSpecial Weather StatementDLHSaint Louis27 min
Aug 7, 11:22 PM CDTSpecial Weather StatementDLHCrow Wing23 min
Aug 7, 11:33 PM CDTSpecial Weather StatementDLHCarlton27 min
Aug 7, 11:37 PM CDTSpecial Weather StatementDLHCrow Wing23 min
Aug 8, 12:06 AM CDTSpecial Weather StatementDLHAitkin9 min
Aug 8, 12:18 AM CDTSpecial Marine WarningDLH42 min
Aug 8, 12:21 AM CDTSpecial Weather StatementDLHAitkin24 min
Aug 8, 12:38 AM CDTSpecial Weather StatementDLHCarlton37 min
Aug 8, 12:59 AM CDTSpecial Weather StatementDLHCarlton31 min
Aug 8, 1:21 AM CDTFlash Flood WarningDLHAitkin, Carlton, Pine, Saint Louis3 hr
Aug 8, 1:33 AM CDTSpecial Weather StatementDLHCarlton27 min
Aug 8, 2:04 AM CDTSpecial Weather StatementDLHCarlton26 min
Aug 8, 5:40 AM CDTSpecial Weather StatementDLHKoochiching50 min
Aug 8, 1:42 PM CDTSevere Thunderstorm WarningDLHCass48 min
Aug 8, 2:06 PM CDTTornado Warning Tornado observedDLHCass, Crow Wing24 min
Aug 8, 12:03 AM CDTSpecial Weather StatementDLHDouglas12 min
Aug 8, 12:24 AM CDTSpecial Weather StatementDLHDouglas36 min
Aug 8, 12:56 AM CDTSpecial Weather StatementDLHBayfield34 min
Aug 8, 1:30 AM CDTSpecial Weather StatementDLHAshland, Bayfield30 min
Aug 8, 2:02 AM CDTSpecial Weather StatementDLHAshland28 min
Aug 8, 2:56 AM CDTSpecial Weather StatementDLHIron, Sawyer49 min
Aug 8, 3:29 AM CDTSpecial Weather StatementDLHIron, Price, Sawyer91 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2020Every severe thunderstorm warning in 2020

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.