Alert archive / Iowa / Tornado Watches in 1997

Tornado Watch 647

July 24, 19974 states

The Storm Prediction Center issued this tornado watch at Jul 24, 1997, 4:30 PM CDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 24, 1997, 4:30 PM CDT (21:30 UTC)
Expired
Jul 24, 1997, 10:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 49 counties

Buena Vista County, IA, Calhoun County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Sioux County, IA, Webster County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Martin County, MN, Murray County, MN, Nobles County, MN, Rock County, MN, Watonwan County, MN, Antelope County, NE, Boone County, NE, Cedar County, NE, Dakota County, NE, Dixon County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Stanton County, NE, Thurston County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Hutchinson County, SD, Lincoln County, SD, McCook County, SD, Minnehaha County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 60 km from the middle of the area, began a volume at 21:31 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 nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.5 hours before the alert went out and 198 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 1997-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2438 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 12:00Z on 1997-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 square meters per square second.1939Sfc1 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
2438 J/kg
Mixed-layer CIN
-149 J/kg
Mixed-layer LCL
1160 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 23, 8:30 PM CDTSevere Thunderstorm WatchSPCAurora, Bennett, Brule, Buffalo, Campbell, Charles Mix and 24 more6 hr
Jul 24, 2:00 AM CDTSevere Thunderstorm WatchSPCBeadle, Brookings, Brown, Buffalo, Clark, Codington and 18 more5 hr

Nearby

Tornado Watches in Iowa, 1997Tornado Watches in Nebraska, 1997Tornado Watches in South Dakota, 1997Every tornado watch 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.