Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 137, NWS Twin Cities, MN

December 15, 20214 counties in Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Dec 15, 2021, 5:25 PM CST for 4 counties in Minnesota. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Dec 15, 2021, 5:25 PM CST (23:25 UTC)
Expired: Dec 15, 2021, 6:00 PM CST
In force: 35 min
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Tornado: Possible
Damage threat: Considerable
Hail: 0.75 in
Wind: 70.0 mph

Counties Blue Earth County, MN, Faribault County, MN, Martin County, MN, Watonwan County, MN

The radar

The Minneapolis radar (KMPX), 120 km from the middle of the area, began a volume at 23:27 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.

Issued	Product	Office	Lasted
Dec 15, 1:23 PM CST	Tornado Watch	SPC	7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 11.4 hours before the alert went out and 119 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: 1 J/kg
Mixed-layer CIN: -51 J/kg
Mixed-layer LCL: 455 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 251 m²/s²
0-3 km storm-relative helicity: 291 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

773 
WUUS53 KMPX 152325
SVRMPX
MNC013-043-091-165-160000-
/O.NEW.KMPX.SV.W.0137.211215T2325Z-211216T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
525 PM CST Wed Dec 15 2021

The National Weather Service in the Twin Cities has issued a

* Severe Thunderstorm Warning for...
  Faribault County in south central Minnesota...
  Martin County in south central Minnesota...
  Blue Earth County in south central Minnesota...
  Watonwan County in south central Minnesota...

* Until 600 PM CST.

* At 523 PM CST, severe thunderstorms were located along a line
  extending from near Jackson In Jackson County to 12 miles north of
  Dakota City, moving northeast at 80 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Trimont around 535 PM CST.

Other locations in the path of these severe thunderstorms include St.
James, Truman, Lewisville, Madelia and Lake Crystal.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for south central
Minnesota.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across western Iowa. SEEK SHELTER NOW inside a sturdy 
structure and stay away from windows! A Tornado Watch remains in 
effect until 800 PM CST for south central Minnesota.

&&

LAT...LON 4351 9485 4386 9486 4411 9448 4411 9437
      4426 9437 4426 9434 4420 9420 4385 9377
      4384 9365 4350 9365
TIME...MOT...LOC 2323Z 231DEG 69KT 4365 9498 4289 9414 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Dye

2 follow-up statements

573 
WWUS53 KMPX 152344
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
544 PM CST Wed Dec 15 2021

MNC013-043-091-165-160000-
/O.CON.KMPX.SV.W.0137.000000T0000Z-211216T0000Z/
Faribault MN-Martin MN-Blue Earth MN-Watonwan MN-
544 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CST
FOR FARIBAULT...MARTIN...BLUE EARTH AND WATONWAN COUNTIES...

At 542 PM CST, severe thunderstorms were located along a line
extending from 8 miles south of St. James to Eagle Lake, moving 
northeast at 80 mph. Spencer, Iowa reported a 54 MPH gust with this 
line of storms. 

HAZARD...70 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Lewisville, Madelia and Lake Crystal.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for south central
Minnesota.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across northwestern Iowa. SEEK SHELTER NOW inside a 
sturdy structure and stay away from windows.
 
&&

LAT...LON 4351 9485 4386 9486 4411 9448 4411 9437
      4426 9437 4426 9434 4420 9420 4385 9377
      4384 9365 4350 9365
TIME...MOT...LOC 2342Z 231DEG 69KT 4387 9460 4311 9376 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Dye

004 
WWUS53 KMPX 152355
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
555 PM CST Wed Dec 15 2021

MNC013-043-091-165-160005-
/O.EXP.KMPX.SV.W.0137.000000T0000Z-211216T0000Z/
Faribault MN-Martin MN-Blue Earth MN-Watonwan MN-
555 PM CST Wed Dec 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR FARIBAULT...MARTIN...BLUE
EARTH AND WATONWAN COUNTIES WILL EXPIRE AT 600 PM CST...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Tornado Watch remains in effect until 800 PM CST for south central
Minnesota.

LAT...LON 4351 9485 4386 9486 4411 9448 4411 9437
      4426 9437 4426 9434 4420 9420 4385 9377
      4384 9365 4350 9365
TIME...MOT...LOC 2355Z 231DEG 69KT 4403 9433 4327 9349 

$$

Dye

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 15, 3:28 AM CST	Winter Weather Advisory	MPX	Benton, Chippewa, Douglas, Kanabec, Kandiyohi, Lac qui Parle and 11 more	31 hr
Dec 15, 3:34 AM CST	Dense Fog Advisory	MPX	Anoka, Benton, Blue Earth, Brown, Carver, Chippewa and 36 more	11 hr
Dec 15, 3:38 PM CST	Winter Storm Warning	MPX	Douglas, Pope, Stevens, Todd	18 hr

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.