Alert archive / Iowa / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 21, NWS Omaha, NE

April 6, 1998Mills County, Iowa; Cass County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Apr 6, 1998, 8:11 PM CDT for Mills County, Iowa; Cass County, Nebraska. It was in force for 49 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 6, 1998, 8:11 PM CDT (01:11 UTC)
Expired
Apr 6, 1998, 9:00 PM CDT
In force
49 min
Issued by
NWS Omaha, NE
Area
Whole counties

Counties Mills County, IA, Cass County, NE

The radar

The Omaha radar (KOAX), 56 km from the middle of the area, began a volume at 01:12 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.

IssuedProductOfficeLasted
Apr 6, 6:30 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.2 hours before the alert went out and 56 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 00:00Z on 1998-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 25 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, Omaha, NE at 00:00Z on 1998-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 158 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
25 J/kg
Mixed-layer CIN
-306 J/kg
Mixed-layer LCL
711 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
158 m²/s²
0-3 km storm-relative helicity
414 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.2

Open this sounding in Storm Lab

The text

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

716 
WUUS1 KOMA 070112 RRA
SVROMA
IAC129-NEC025-067-109-131-070200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
811 PM CDT MON APR 6 1998

* SEVERE THUNDERSTORM WARNING FOR
  CASS COUNTY IN SOUTHEASTERN NEBRASKA
  LANCASTER COUNTY IN SOUTHEASTERN NEBRASKA
  GAGE COUNTY IN SOUTHEASTERN NEBRASKA
  WESTERN OTOE COUNTY IN SOUTHEASTERN NEBRASKA
  WESTERN MILLS COUNTY IN SOUTHWESTERN IOWA

* UNTIL 900 PM CDT
 
* SOME LOCATIONS AFFECTED
  LINCOLN
  BEATRICE
  SYRACUSE
  PLATTSMOUTH
  EAGLE
  GLENWOOD

* AT 807 PM DOPPLER RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS
FROM AROUND BEATRICE TO LINCOLN TO PLATTSMOUTH TO GLENWOOD IOWA.
MOVEMENT WAS NORTHEAST AT 20 MPH.
 
TAKE SHELTER IN A REINFORCED BUILDING ON THE LOWEST FLOOR.  DRIVERS
SHOULD WATCH OUT FOR WATER OVER ROADS...IN UNDERPASSES AND NEAR
STREAMS.  REPORTS OF SEVERE WEATHER OR DAMAGE CAN BE GIVEN TO A
LAW ENFORCEMENT AGENCY FOR RELAY TO THE NATIONAL WEATHER SERVICE.

CHERMOK

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 7:05 PM CDTSevere Thunderstorm WarningOAXMills, Pottawattamie60 min
Apr 6, 7:32 PM CDTTornado WarningOAXMills33 min
Apr 6, 8:06 PM CDTTornado WarningOAXMills, Pottawattamie29 min
Apr 6, 7:05 PM CDTSevere Thunderstorm WarningOAXCass, Gage, Lancaster, Otoe60 min
Apr 6, 8:11 PM CDTSevere Thunderstorm WarningOAXGage, Lancaster, Otoe49 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1998Severe Thunderstorm Warnings in Nebraska, 1998Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.