Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 56, NWS Quad Cities, IA

August 16, 1997Johnson County, Washington County, Iowa

NWS Quad Cities, IA issued this tornado warning at Aug 16, 1997, 9:28 PM CDT for Johnson County, Washington County, Iowa. It was in force for 47 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: Aug 16, 1997, 9:28 PM CDT (02:28 UTC)
Expired: Aug 16, 1997, 10:15 PM CDT
In force: 47 min
Issued by: NWS Quad Cities, IA
Area: Whole counties

Counties Johnson County, IA, Washington County, IA

The radar

The Quad Cities radar (KDVN), 90 km from the middle of the area, began a volume at 02:45 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.

Issued	Product	Office	Lasted
Aug 16, 5:15 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.5 hours before the alert went out and 97 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: 6428 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 765 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 2.3
Supercell composite: 10.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KMLI 170229 RRA
TORMLI
IAC103-183-170315-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
928 PM CDT SAT AUG 16 1997

* TORNADO WARNING FOR
  SOUTHERN JOHNSON COUNTY IN EAST CENTRAL IOWA
  NORTHERN WASHINGTON COUNTY IN SOUTHEASTERN IOWA

* UNTIL 1015 PM CDT
 
* SOME LOCATIONS AFFECTED
  RIVER JCT                          AROUND 935 PM CDT
  RIVERSIDE                          AROUND 935 PM CDT
  LONE TREE                          AROUND 945 PM CDT
  HASKINS                            AROUND 1000 PM CDT

* AT 926 PM CDT...A POSSIBLE TORNADO WAS INDICATED BY QUAD CITIES
  IA DOPPLER RADAR 11 MILES SOUTH OF IOWA CITY OR 3 MILES WEST OF
  RIVER JCT MOVING SOUTHEAST AT 10 MPH.
 
THIS IS A DANGEROUS STORM. ACT QUICKLY. GO TO A SHELTER BELOW
GROUND IF AVAILABLE. OTHERWISE GO TO AN INTERIOR ROOM ON THE
LOWEST FLOOR. AVOID WINDOWS. ABANDON CARS AND MOBILE HOMES...TAKE
COVER IN A REINFORCED BUILDING OR GET INTO A DITCH OR CULVERT.

TEH/BLH

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 7:43 PM CDT	Tornado Warning	DVN	Scott	32 min
Aug 16, 8:21 PM CDT	Tornado Warning	DVN	Cedar	59 min
Aug 16, 8:35 PM CDT	Tornado Warning	DVN	Muscatine	65 min
Aug 16, 9:33 PM CDT	Tornado Warning	DVN	Muscatine	62 min
Aug 16, 10:31 PM CDT	Flash Flood Warning	DVN	Muscatine	5 hr
Aug 17, 12:27 AM CDT	Flash Flood Warning	DVN	Cedar, Johnson	8 hr
Aug 17, 1:04 AM CDT	Flash Flood Warning	DVN	Keokuk, Washington	7 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.