Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 21, NWS Duluth, MN

July 23, 2021Cook County, Lake County, Saint Louis County, Minnesota

NWS Duluth, MN issued this severe thunderstorm warning at Jul 23, 2021, 6:28 PM CDT for Cook County, Lake County, Saint Louis County, Minnesota. It was in force for 62 min. 5 reports 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
Jul 23, 2021, 6:28 PM CDT (23:28 UTC)
Expired
Jul 23, 2021, 7:30 PM CDT
In force
62 min
Issued by
NWS Duluth, MN
Area
Storm-based polygon
Hail
0.88 in
Wind
70.0 mph

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

The radar

The Duluth radar (KDLH), 145 km from the middle of the area, began a volume at 23:28 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

TimeReportWhereRemark
Jul 23, 6:41 PM CDTTSTM WND DMG10 Nnw Soudan, MNMULTIPLE CANOES FLIPPED OVER FROM THUNDERSTORM WIND GUSTS ON TROUT LAKE. CREW OF ONE CANOE UNACCOUNTED FOR. ADDITIONAL WATER EMERGENCIES ONGOING IN OTHER PORTIONS OF THE BOUNDARY WATERS CANOE AREA.
Jul 23, 6:46 PM CDTTSTM WND DMGEly, MNNUMEROUS REPORTS OF TREES DOWN IN ELY WITH MULTIPLE ROADS BLOCKED. TIME ESTIMATED BY RADAR.
Jul 23, 6:46 PM CDTTSTM WND DMGEly, MNPHOTO AND REPORT RECEIVED VIA SOCIAL MEDIA OF TREES DOWN AND DAMAGE TO TENTS AT A FESTIVAL IN DOWNTOWN ELY. TIME ESTIMATED BY RADAR.
Jul 23, 6:47 PM CDTTSTM WND DMGEly, MNPHOTOS AND MEASUREMENTS WERE RECEIVED FROM THE DAMAGED TREES IN WHITESIDE PARK. THE TWO LARGEST TREES WERE ELMS. ONE WAS UPROOTED AND HAD A DIAMETER OF 1 FOOT AT THE BASE OF THE TRUNK. THE SECOND TREE WAS 27 INCHES IN DIAMETER AND WAS COMPLETELY SNAPPED OFF AB
Jul 23, 7:00 PM CDTTSTM WND GST 565 Wnw Tower, MNA PERSONAL WEATHER STATION ON THE SOUTH SHORE OF LAKE VERMILION REPORTED A GUST TO 55.5 MPH.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Jul 23, 4:48 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 11.5 hours before the alert went out and 134 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, International Fa, MN at 12:00Z on 2021-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 470 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, International Fa, MN at 12:00Z on 2021-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 square meters per square second.19395878Sfc1 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
470 J/kg
Mixed-layer CIN
-131 J/kg
Mixed-layer LCL
725 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

093 
WUUS53 KDLH 232328
SVRDLH
MNC031-075-137-240030-
/O.NEW.KDLH.SV.W.0021.210723T2328Z-210724T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Duluth MN
628 PM CDT Fri Jul 23 2021

The National Weather Service in Duluth MN has issued a

* Severe Thunderstorm Warning for...
  West central Cook County in northeastern Minnesota...
  Northeastern St. Louis County in northeastern Minnesota...
  Northern Lake County in northeastern Minnesota...

* Until 730 PM CDT.

* At 627 PM CDT, severe thunderstorms were located along a line 
  extending from Boundary Waters Canoe Area Wilderness northwest of 
  Ely, to 11 miles northwest of Burntside Lake, to near Lake 
  Vermilion, moving east at 50 mph.

  HAZARD...70 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Severe thunderstorms will be near...
  Burntside Lake around 645 PM CDT.

Other locations in the path of these severe thunderstorms include
Ely, Winton, Robinson, White Iron Lake, Fall Lake, Basswood Lake,
Snowbank Lake, Birch Lake, Babbitt, Forest Center and Little Saganaga
Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail, damaging winds, and continuous cloud-to-ground lightning
is occurring with these storms. Move indoors immediately. Lightning
is one of nature's leading killers. Remember, if you can hear
thunder, you are close enough to be struck by lightning.

&&

LAT...LON 4832 9206 4823 9195 4824 9190 4821 9186
      4820 9172 4812 9171 4810 9156 4805 9157
      4807 9149 4805 9142 4808 9126 4811 9120
      4802 9085 4778 9114 4761 9152 4793 9270
TIME...MOT...LOC 2327Z 287DEG 42KT 4814 9205 4803 9220 4792 9245 

HAIL...0.88IN
WIND...70MPH
 
$$

Unruh/Huyck
3 follow-up statements
790 
WWUS53 KDLH 232347
SVSDLH

Severe Weather Statement
National Weather Service Duluth MN
647 PM CDT Fri Jul 23 2021

MNC031-075-137-240030-
/O.CON.KDLH.SV.W.0021.000000T0000Z-210724T0030Z/
Cook MN-St. Louis MN-Lake MN-
647 PM CDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR WEST CENTRAL COOK...EAST CENTRAL ST. LOUIS AND NORTHERN LAKE
COUNTIES...

At 646 PM CDT, severe thunderstorms were located along a line 
extending from Boundary Waters Canoe Area Wilderness near Ely, to 
near Winton, to Burntside Lake, to near Robinson, moving east at 50 
mph.

HAZARD...70 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
  Ely, Winton, White Iron Lake, Fall Lake, Birch Lake, Babbitt, 
  Basswood Lake, Snowbank Lake and Forest Center.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud-to-ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4787 9246 4825 9199 4825 9197 4823 9195
      4824 9191 4824 9189 4821 9186 4820 9172
      4812 9171 4810 9156 4805 9157 4807 9149
      4805 9142 4808 9126 4811 9120 4802 9085
      4778 9114 4761 9152
TIME...MOT...LOC 2346Z 290DEG 45KT 4807 9182 4796 9186 4791 9196 4788
9209

HAIL...0.88IN
WIND...70MPH
 
$$

Unruh/Huyck
865 
WWUS53 KDLH 240005
SVSDLH

Severe Weather Statement
National Weather Service Duluth MN
705 PM CDT Fri Jul 23 2021

MNC031-075-137-240030-
/O.CON.KDLH.SV.W.0021.000000T0000Z-210724T0030Z/
Cook MN-St. Louis MN-Lake MN-
705 PM CDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR WEST CENTRAL COOK...EAST CENTRAL ST. LOUIS AND NORTHERN LAKE
COUNTIES...

At 703 PM CDT, severe thunderstorms were located along a line 
extending from Boundary Waters Canoe Area Wilderness near Ely, to 9 
miles southeast of White Iron Lake, to near Birch Lake, moving east 
at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
  Snowbank Lake and Forest Center.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

If on one of the many area lakes, get away from the water and move 
indoors or inside a vehicle. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now! Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 4778 9214 4781 9222 4792 9195 4811 9164
      4810 9156 4805 9157 4807 9149 4805 9142
      4808 9126 4811 9120 4802 9085 4778 9114
      4761 9152
TIME...MOT...LOC 0003Z 288DEG 45KT 4801 9155 4779 9165 4773 9192 

HAIL...1.00IN
WIND...70MPH
 
$$

Unruh/Huyck
889 
WWUS53 KDLH 240023
SVSDLH

Severe Weather Statement
National Weather Service Duluth MN
723 PM CDT Fri Jul 23 2021

MNC031-075-137-240030-
/O.CON.KDLH.SV.W.0021.000000T0000Z-210724T0030Z/
Cook MN-St. Louis MN-Lake MN-
723 PM CDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR WEST CENTRAL COOK...NORTHEASTERN ST. LOUIS AND NORTHERN LAKE
COUNTIES...

At 722 PM CDT, severe thunderstorms were located along a line 
extending from Boundary Waters Canoe Area Wilderness near Snowbank 
Lake, to near Forest Center, to 9 miles southeast of Birch Lake, 
moving east at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Babbitt, Birch Lake, Snowbank Lake, southern Boundary Waters Canoe
Area Wilderness, Forest Center, Little Saganaga Lake, White Iron
Lake, Basswood Lake, Ensign Lake, Kekekabic Lake, Bald Eagle Lake,
Gabbro Lake, Alice Lake, Ojibway Lake, Kawishiwi Lake, Isabella Lake,
Disappointment Lake, Greenstone Lake, Lake Three, and Gabimichigami
Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

If on one of the many area lakes, get away from the water and move 
indoors or inside a vehicle. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now! Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 4775 9200 4788 9174 4807 9150 4807 9149
      4805 9142 4808 9126 4811 9120 4802 9085
      4778 9114 4761 9152
TIME...MOT...LOC 0022Z 287DEG 42KT 4796 9128 4774 9138 4768 9165 

HAIL...1.00IN
WIND...70MPH
 
$$

Unruh/Huyck

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 22, 7:38 PM CDTHeat AdvisoryDLHPine23 hr
Jul 23, 3:44 PM CDTSpecial Weather StatementDLHKoochiching16 min
Jul 23, 3:57 PM CDTSpecial Weather StatementDLHKoochiching18 min
Jul 23, 4:11 PM CDTSpecial Weather StatementDLHKoochiching19 min
Jul 23, 4:28 PM CDTSevere Thunderstorm WarningDLHKoochiching, Saint Louis62 min
Jul 23, 4:46 PM CDTSpecial Weather StatementDLHKoochiching14 min
Jul 23, 4:50 PM CDTSevere Thunderstorm WarningDLHKoochiching22 min
Jul 23, 4:59 PM CDTSevere Thunderstorm WarningDLHItasca, Koochiching38 min
Jul 23, 5:34 PM CDTSevere Thunderstorm WarningDLHItasca45 min
Jul 23, 5:42 PM CDTSpecial Weather StatementDLH18 min
Jul 23, 6:05 PM CDTSpecial Weather StatementDLH25 min
Jul 23, 6:35 PM CDTSpecial Weather StatementDLHItasca25 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021Every severe thunderstorm warning in 2021

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.