Alert archive / Minnesota / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 146, NWS Twin Cities, MN

September 4, 2018Freeborn County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Sep 4, 2018, 5:55 PM CDT for Freeborn County, Minnesota. It was in force for 65 min. 1 report 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
Sep 4, 2018, 5:55 PM CDT (22:55 UTC)
Expired
Sep 4, 2018, 7:00 PM CDT
In force
65 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

County Freeborn County, MN

The radar

The Minneapolis radar (KMPX), 133 km from the middle of the area, began a volume at 22:57 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
Sep 4, 6:38 PM CDTTORNADO1 Sw Myrtle, MNRECEIVED CALL FROM FREEBORN COUNTY EMERGENCY MANAGER THAT A DRIVER ON HWY 13 NEAR MYRTLE SAW A TORNADO TO THE SOUTH OF MYRTLE. TORNADO WAS IN PROGRESS. NO PHOTO WAS PROVIDED.

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
Sep 4, 3:35 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.9 hours before the alert went out and 133 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 12:00Z on 2018-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 106 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, Minneapolis, MN at 12:00Z on 2018-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 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
106 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
667 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

165 
WUUS53 KMPX 042255
SVRMPX
MNC047-050000-
/O.NEW.KMPX.SV.W.0146.180904T2255Z-180905T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
555 PM CDT TUE SEP 4 2018

The National Weather Service in The Twin Cities has issued a

* Severe Thunderstorm Warning for...
  Eastern Freeborn County in south central Minnesota...

* Until 700 PM CDT.

* At 554 PM CDT, a severe thunderstorm was located near Emmons, or 9
  miles west of Northwood, moving northeast at 30 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Albert Lea, Glenville, Emmons, London, Hollandale, Hayward, Twin
  Lakes and Myrtle.

This includes the following highways...
 Interstate 35 between mile markers 1 and 16.
 Interstate 90 between mile markers 158 and 173.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

A Tornado Watch remains in effect until 1000 PM CDT for south central
Minnesota.

LAT...LON 4385 9320 4384 9305 4350 9305 4350 9353
      4351 9353
TIME...MOT...LOC 2254Z 218DEG 27KT 4348 9341 

TORNADO...POSSIBLE
HAIL...0.75IN
WIND...60MPH
 
$$

ETA
1 follow-up statement
416 
WWUS53 KMPX 042348
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
648 PM CDT TUE SEP 4 2018

MNC047-050000-
/O.CON.KMPX.SV.W.0146.000000T0000Z-180905T0000Z/
Freeborn MN-
648 PM CDT TUE SEP 4 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM CDT
FOR EASTERN FREEBORN COUNTY...

At 648 PM CDT, a severe thunderstorm was located near Brookside
Campground, or 9 miles northwest of Austin, moving northeast at 30
mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
London and Myrtle. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

A Tornado Watch remains in effect until 1000 PM CDT for south central
Minnesota.

LAT...LON 4350 9326 4385 9316 4384 9305 4350 9305
TIME...MOT...LOC 2348Z 218DEG 27KT 4380 9307 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

ETA

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 4, 3:15 AM CDTFlash Flood WatchMPXBlue Earth, Brown, Dakota, Faribault, Freeborn, Goodhue and 7 more25 hr
Sep 4, 2:15 PM CDTSpecial Weather StatementMPXFreeborn30 min
Sep 4, 3:29 PM CDTTornado WarningMPXSteele31 min
Sep 4, 6:10 PM CDTTornado WarningMPXFreeborn35 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2018Every severe thunderstorm warning in 2018

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.