Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 76, NWS Omaha, NE

July 6, 1998Harrison County, Iowa

NWS Omaha, NE issued this tornado warning at Jul 6, 1998, 6:49 PM CDT for Harrison County, Iowa. It was in force for 61 min. 2 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 6, 1998, 6:49 PM CDT (23:49 UTC)
Expired
Jul 6, 1998, 7:50 PM CDT
In force
61 min
Issued by
NWS Omaha, NE
Area
Whole counties

County Harrison County, IA

The radar

The Omaha radar (KOAX), 61 km from the middle of the area, began a volume at 23:50 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
Jul 6, 7:15 PM CDTThunderstorm Wind 52Little Sioux, IATree limbs downed.
Jul 6, 7:20 PM CDTThunderstorm Wind 52Logan, IA

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 6, 5:15 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.8 hours before the alert went out and 61 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 1998-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1215 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 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 1998-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 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
1215 J/kg
Mixed-layer CIN
-143 J/kg
Mixed-layer LCL
979 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
-19 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.

014 
WFUS1 KOMA 062350 RRA
TOROMA
IAC085-070050-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
649 PM CDT MON JUL 6 1998

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  HARRISON COUNTY IN SOUTHWESTERN IOWA

* UNTIL 750 PM CDT

* AT 650 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF TORNADIC STORMS FROM NEAR MOOREHEAD IOWA TO NEAR LITTLE
  SIOUX...OR 40 TO 50 MILES SOUTH OF SIOUX CITY..  MOVEMENT WAS
  SOUTHEAST AT 30 MPH.

A TORNADO WAS REPORTED NEAR BLENCOE IOWA AT 640 PM CDT.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...LITTLE SIOUX...
PISGAH...MONDAMIN...MAGNOLIA AND WOODBINE.


TORNADOES MAY OCCUR NEAR THE LEADING EDGE OF THIS STORM AND COULD
BE DIFFICULT TO SEE BECAUSE OF THE VERY HEAVY RAIN.  TAKE SHELTER
ON THE LOWEST LEVEL OF YOUR HOME OR BUSINESS.

BCM


&

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 6, 4:45 PM CDT, 2 hours 4 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-071200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
445 PM CDT MON JUL 6 1998

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

SPOTTER ACTION...
STORM SPOTTER ACTIVATION WILL BE REQUIRED ACROSS EASTERN NEBRASKA
AND SOUTHWEST IOWA THIS EVENING.

DISCUSSION...
SEVERE THUNDERSTORMS WERE MOVING INTO NORTHEAST NEBRASKA LATE THIS
AFTERNOON WITH A LINE OF STORMS DEVELOPING INTO CENTRAL NEBRASKA.
THIS STORM COMPLEX WILL CONTINUE TO MOVE EAST DURING THE EVENING
AND IS EXPECTED TO REACH EAST CENTRAL AND SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA BETWEEN 7 AND 10 PM.  LARGE HAIL AND DAMAGING WINDS
WILL BE THE PRIMARY THREAT WITH ISOLATED TORNADOES POSSIBLE.

VERY HEAVY RAIN IS ALSO LIKELY WITH THESE STORMS AND SINCE THE GROUND
IS ALREADY SATURATED FROM RAINFALL OVER THE PAST TWO DAYS SMALLER
STREAMS AND CRE@EKS WILL TEND TO FLOOD QUICKLY.

FOBERT
Special weather statement, Jul 6, 4:45 PM CDT, 2 hours 4 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-071200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
445 PM CDT MON JUL 6 1998

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

SPOTTER ACTION...
STORM SPOTTER ACTIVATION WILL BE REQUIRED ACROSS EASTERN NEBRASKA
AND SOUTHWEST IOWA THIS EVENING.

DISCUSSION...
SEVERE THUNDERSTORMS WERE MOVING INTO NORTHEAST NEBRASKA LATE THIS
AFTERNOON WITH A LINE OF STORMS DEVELOPING INTO CENTRAL NEBRASKA.
THIS STORM COMPLEX WILL CONTINUE TO MOVE EAST DURING THE EVENING
AND IS EXPECTED TO REACH EAST CENTRAL AND SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA BETWEEN 7 AND 10 PM.  LARGE HAIL AND DAMAGING WINDS
WILL BE THE PRIMARY THREAT WITH ISOLATED TORNADOES POSSIBLE.

VERY HEAVY RAIN IS ALSO LIKELY WITH THESE STORMS AND SINCE THE GROUND
IS ALREADY SATURATED FROM RAINFALL OVER THE PAST TWO DAYS SMALLER
STREAMS AND CRE@EKS WILL TEND TO FLOOD QUICKLY.

FOBERT

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 6:16 PM CDTSevere Thunderstorm WarningOAXMonona64 min
Jul 6, 6:34 PM CDTTornado WarningOAXMonona61 min

Nearby

Tornado Warnings in Iowa, 1998Every tornado warning in 1998Tornadoes 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.