Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 8, NWS Sioux Falls, SD

July 7, 1997Plymouth County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jul 7, 1997, 6:47 PM CDT for Plymouth County, Iowa. It was in force for 33 min. 1 report 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 7, 1997, 6:47 PM CDT (23:47 UTC)
Expired: Jul 7, 1997, 7:20 PM CDT
In force: 33 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties

County Plymouth County, IA

The radar

The Sioux Falls radar (KFSD), 103 km from the middle of the area, began a volume at 23:46 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

Time	Report	Where	Remark
Jul 7, 7:19 PM CDT	Tornado F0	Kingsley, IA	A tornado resulted in no reported damage.

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.

Issued	Product	Office	Lasted
Jul 7, 4:00 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.8 hours before the alert went out and 158 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 929 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 73 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 072350 RRA
TORFSD
IAC149-080020-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
647 PM CDT MON JUL 7 1997

* TORNADO WARNING FOR
  EASTERN PLYMOUTH COUNTY - IN NORTHWESTERN IOWA

* UNTIL 720 PM CDT

* SOME AREAS AFFECTED
  OLEARY                   AROUND 650 PM CDT
  REMSEN                   AROUND 655 PM CDT

* AT 644 PM CDT...NATIONAL WEATHER SERVICE SPOTTERS REPORTED A
  SEVERE THUNDERSTORM 25 MILES NORTHEAST OF SIOUX CITY  OR 4 MILES
  SOUTHWEST OF REMSEN MOVING EAST AT 30 MPH.

AT 640 PM A TORNADO WAS REPORTED 3 MILES EAST AND 1 MILE SOUTH OF
LE MARS.

A TORNADO WATCH IS ALSO IN EFFECT.  SEVERE THUNDERSTORMS CAN AND
OCCASIONALLY DO PRODUCE TORNADOES.

DO NOT USE YOUR CAR TO OUTRUN A TORNADO.  CARS ARE EASILY TOSSED
AROUND BY TORNADIC WINDS.  IF YOU ARE CAUGHT IN THE PATH OF A
TORNADO...LEAVE THE CAR AND GO TO A STRONG BUILDING.  IF NO
STRUCTURE IS NEARBY...SEEK SHELTER IN A DITCH OR LOW FSPOT.

BLOOM

&

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 5:01 PM CDT	Tornado Warning	FSD	Lyon, Sioux	44 min
Jul 7, 5:40 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	30 min
Jul 7, 6:15 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	30 min
Jul 7, 6:47 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	33 min

Nearby

Tornado Warnings in Iowa, 1997 Every tornado warning in 1997 Tornadoes 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.