Alert archive / Iowa / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 113, NWS Sioux Falls, SD

July 18, 1990Lyon County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 18, 1990, 12:52 PM CDT for Lyon County, Iowa. It was in force for 38 min.

The area

The counties it named.

The facts

Issued
Jul 18, 1990, 12:52 PM CDT (17:52 UTC)
Expired
Jul 18, 1990, 1:30 PM CDT
In force
38 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Lyon County, IA

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

Omaha, NE (KOAX), launched 12:00Z, 5.9 hours before the alert went out and 230 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, Omaha, NE at 12:00Z on 1990-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 12:00Z on 1990-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3632 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
138 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 KFSD 181758 COR
SVRFSD
IAC119-181830-

BULLETIN - IMMEDIATE BROADCAST REQUESTED...CORRECTION
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1252 PM CDT WED JUL 18 1990

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  130 PM CDT
FOR PEOPLE IN THE FOLLOWING COUNTY...

IN NORTHWEST IOWA
          ...EASTERN LYON

SOME CITIES INCLUDED IN THIS WARNING ARE EDNA...GEORGE AND LITTLE ROCK
IN NORTHWEST IOWA.

AT 1245 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM 35 MILES SOUTHEAST
SIOUX FALLS IN NORTHWEST IOWA BETWEEN EDNA AND GEORGE MOVING EAST AT
20 MPH.
<
IF YOU ARE IN THE PATH OF THIS STORM...YOU SHOULD GET TO A
REINFORCED SHELTER. A SEVERE THUNDERSTORM PRODUCES WINDS IN EXCESS
OF 60 MPH...HAIL 3/4 INCH OR LARGER...DEADLY LIGHTNING...AND HEAVY
RAIN THAT CAN QUICKLY FLOOD A LOW LYING AREA.
BEHREND

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 18, 6:01 AM CDTSevere Thunderstorm WarningFSDLyon29 min
Jul 18, 6:26 AM CDTSevere Thunderstorm WarningFSDLyon, Osceola34 min
Jul 18, 8:40 AM CDTSevere Thunderstorm WarningFSDSioux35 min
Jul 18, 9:16 AM CDTSevere Thunderstorm WarningFSDO'Brien, Sioux29 min
Jul 18, 10:54 AM CDTSevere Thunderstorm WarningFSDSioux66 min
Jul 18, 12:12 PM CDTSevere Thunderstorm WarningFSDLyon33 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1990Every severe thunderstorm warning in 1990

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.