Alert archive / North Dakota / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 30, NWS Grand Forks, ND

July 20, 1987Cass County, North Dakota

NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 20, 1987, 6:22 AM CDT for Cass County, North Dakota. It was in force for 58 min.

The area

The counties it named.

The facts

Issued
Jul 20, 1987, 6:22 AM CDT (11:22 UTC)
Expired
Jul 20, 1987, 7:20 AM CDT
In force
58 min
Issued by
NWS Grand Forks, ND
Area
Whole counties

County Cass County, ND

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Aberdeen, SD (KHON), launched 00:00Z, 11.4 hours before the alert went out and 243 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, Aberdeen, SD at 00:00Z on 1987-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2687 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, Aberdeen, SD at 00:00Z on 1987-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
2687 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
1437 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
0.4
Supercell composite
3.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFAR 201124
SVRFAR
NDC017-201220-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FARGO ND
622 AM CDT MON JUL 20 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 720 AM CDT FOR PEOPLE IN THE FOLLOWING
COUNTIES OF

EAST CENTRAL NORTH DAKOTA...CASS AND THE CITIES OF FARGO/MOORHEAD

AT 620 AM CDT RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS IN
EXTREME EASTERN BARNES COUNTY MOVING EAST AT 45 TO 50 MPH.

REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE DAMAGING WINDS IN EXCESS
OF 58 MPH AND/OR HAIL 3/4 INCH OR LARGER...DEADLY LIGHTNING...
AND HEAVY RAINS THAT CAN QUICKLY FLOOD A LOW LYING AREA.

THIS IS A DANGEROUS STORM.  TAKE COVER IMMEDIATELY.

EWENS

The office that day

Everything else NWS Grand Forks, ND issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 12:34 AM CDTSevere Thunderstorm WarningFGFRansom, Richland, Sargent56 min
Jul 20, 2:08 AM CDTSevere Thunderstorm WarningFGFDickey, LaMoure52 min
Jul 20, 2:59 AM CDTSevere Thunderstorm WarningFGFDickey, LaMoure, Ransom61 min
Jul 20, 2:59 AM CDTSevere Thunderstorm WarningFGFSargent61 min
Jul 20, 3:15 AM CDTSevere Thunderstorm WarningFGFCass60 min
Jul 20, 3:58 AM CDTSevere Thunderstorm WarningFGFRichland62 min

Nearby

Severe Thunderstorm Warnings in North Dakota, 1987Every severe thunderstorm warning in 1987

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.