Alert archive / Minnesota / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 285, NWS Twin Cities, MN

July 20, 1998Brown County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 20, 1998, 10:51 AM CDT for Brown County, Minnesota. It was in force for 64 min. 4 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Jul 20, 1998, 10:51 AM CDT (15:51 UTC)
Expired: Jul 20, 1998, 11:55 AM CDT
In force: 64 min
Issued by: NWS Twin Cities, MN
Area: Whole counties

County Brown County, MN

The radar

The Minneapolis radar (KMPX), 114 km from the middle of the area, began a volume at 15:57 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

Time	Report	Where	Remark
Jul 20, 11:00 AM CDT	Thunderstorm Wind 60	Comfrey, MN	New building construction blown down. Power poles snapped. Estimated windspeed.
Jul 20, 11:08 AM CDT	Thunderstorm Wind 75	Springfield, MN	Roof torn off several homes and businesses. Plate glass windows blown out of auto dealership. Torrential rainfall also resulted in street flooding. Estimated windspeed.
Jul 20, 11:40 AM CDT	Thunderstorm Wind 80	New Ulm, MN	Windows blown out at Flandreau State Park Bldg. 300 trees down. Two trees blown onto camper. Estimated windspeed.
Jul 20, 11:40 AM CDT	Thunderstorm Wind 83	New Ulm, MN	4,000 trees blown down. 10 businesses lost portions of their roof. Mobile home destroyed. Maintenance hangar at airport destroyed, damaging several airplanes. 400 ft TV tower blown down. Poultry bldg levelled at fairgrounds. Reception hall lost its roof.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 3.9 hours before the alert went out and 112 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: 2372 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 103 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMSP 201550 RRA
SVRMSP
MNC015-201655-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1051 AM CDT MON JUL 20 1998

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES/CHANHASSEN HAS
ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  BROWN COUNTY IN SOUTH CENTRAL MINNESOTA

* UNTIL 1155 AM CDT

* AT 1050 AM CDT...DOPPLER RADAR INDICATED A SEVERE STORM WITH LARGE
  HAIL NEAR LAMBERTON OR 20 MILES SOUTH OF REDWOOD FALLS.  THE STORM
  WAS MOVING EAST AT 35 MPH.

* SOME LOCATIONS AFFECTED
    SPRINGFIELD
    COBDEN
    LEAVENWORTH
    SLEEPY EYE

THIS IS A DANGEROUS STORM...WITH LARGE HAIL.  STAY INDOORS AWAY
FROM WINDOWS.

JJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 10:19 AM CDT	Severe Thunderstorm Warning	MPX	Redwood	56 min
Jul 20, 11:35 AM CDT	Severe Thunderstorm Warning	MPX	Blue Earth, Nicollet	60 min
Jul 20, 11:43 AM CDT	Tornado Warning	MPX	Nicollet	32 min
Jul 20, 12:05 PM CDT	Severe Thunderstorm Warning	MPX	Le Sueur	40 min
Jul 20, 12:22 PM CDT	Severe Thunderstorm Warning	MPX	Rice	63 min
Jul 20, 12:51 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	64 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 1998 Every severe thunderstorm warning in 1998

Sources

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