Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 101, NWS Omaha, NE

July 23, 1997Fremont County, Iowa; Otoe County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Jul 23, 1997, 4:56 AM CDT for Fremont County, Iowa; Otoe County, Nebraska. It was in force for 49 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 23, 1997, 4:56 AM CDT (09:56 UTC)
Expired
Jul 23, 1997, 5:45 AM CDT
In force
49 min
Issued by
NWS Omaha, NE
Area
Whole counties

Counties Fremont County, IA, Otoe County, NE

The radar

The Omaha radar (KOAX), 81 km from the middle of the area, began a volume at 09:56 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 23, 5:15 AM CDTThunderstorm Wind 52Nebraska City, NE
Jul 23, 5:30 AM CDTThunderstorm Wind 52Hamburg, 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 nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 9.9 hours before the alert went out and 81 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 1997-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1353 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, Omaha, NE at 00:00Z on 1997-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
1353 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
1400 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KOMA 230957 RRA
SVROMA
IAC071-NEC131-231045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
456 AM CDT WED JUL 23 1997

* SEVERE THUNDERSTORM WARNING FOR
  EASTERN OTOE COUNTY - IN SOUTHEASTERN NEBRASKA
  FREMONT COUNTY - IN SOUTHWESTERN IOWA

* UNTIL 545 AM CDT
 
* SOME LOCATIONS AFFECTED
  ANDERSON                     BY AROUND 455 AM CDT
  SIDNEY                       BY AROUND 455 AM CDT
  RIVERTON                     BY AROUND 515 AM CDT
  HAMBURG                      BY AROUND 515 AM CDT
  FARRAGUT                     BY AROUND 520 AM CDT

* AT 455 AM CDT...A SEVERE THUNDERSTORM WAS INDICATED BY DOPPLER
  RADAR 36 MILES SOUTH OF DOWNTOWN OMAHA OR 8 MILES WEST OF SIDNEY
  MOVING SOUTHEAST AT 25 MPH.
 
THIS SEVERE THUNDERSTORM MAY PRODUCE LARGE HAIL...GREATER THAN 3/4
INCH IN DIAMETER AND DESTRUCTIVE WINDS OF OVER 60 MPH.  GET INTO
A SAFE BUILDING...AWAY FROM WINDOWS OR GLASS DOORS.

SKERRITT

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 8:07 AM CDTSevere Thunderstorm WarningOAXShelby63 min
Jul 23, 4:16 AM CDTSevere Thunderstorm WarningOAXCass, Sarpy44 min
Jul 23, 5:42 AM CDTSevere Thunderstorm WarningOAXNemaha48 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1997Severe Thunderstorm Warnings in Nebraska, 1997Every severe thunderstorm warning in 1997

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.