Alert archive / Iowa / Tornado Watches in 1998

Tornado Watch 394

May 21, 19984 states

The Storm Prediction Center issued this tornado watch at May 21, 1998, 11:30 PM CDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 21, 1998, 11:30 PM CDT (04:30 UTC)
Expired
May 22, 1998, 5:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 38 counties

Adair County, IA, Adams County, IA, Cass County, IA, Fremont County, IA, Harrison County, IA, Madison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Brown County, KS, Doniphan County, KS, Andrew County, MO, Atchison County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Cass County, NE, Dodge County, NE, Douglas County, NE, Gage County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Sarpy County, NE, Saunders County, NE, Washington County, NE

Warnings issued inside it

11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 22, 12:02 AM CDTTornado WarningOAXLancaster33 min
May 22, 12:16 AM CDTTornado WarningOAXLancaster19 min
May 22, 12:19 AM CDTSevere Thunderstorm WarningOAXSarpy46 min
May 22, 12:38 AM CDTSevere Thunderstorm WarningOAXCass62 min
May 22, 12:44 AM CDTSevere Thunderstorm WarningOAXSaunders16 min
May 22, 12:46 AM CDTFlash Flood WarningOAXLancaster, Saunders5 hr
May 22, 1:04 AM CDTSevere Thunderstorm WarningOAXSarpy46 min
May 22, 1:48 AM CDTSevere Thunderstorm WarningOAXGage, Lancaster62 min
May 22, 1:53 AM CDTSevere Thunderstorm WarningDMXAdair32 min
May 22, 2:15 AM CDTSevere Thunderstorm WarningDMXMadison45 min
May 22, 2:36 AM CDTSevere Thunderstorm WarningOAXPage64 min

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.5 hours before the alert went out and 69 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 1998-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 66 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 1998-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 300 square meters per square second.193958Sfc1 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
66 J/kg
Mixed-layer CIN
-295 J/kg
Mixed-layer LCL
905 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
300 m²/s²
0-3 km storm-relative helicity
484 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.6

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
May 21, 11:00 PM CDTSevere Thunderstorm WatchSPCAppanoose, Clarke, Davis, Decatur, Henry, Jefferson and 9 more6 hr
May 22, 2:00 AM CDTSevere Thunderstorm WatchSPCDes Moines, Lee5 hr
May 22, 6:45 PM CDTSevere Thunderstorm WatchSPCCheyenne, Rawlins5 hr
May 22, 5:30 PM CDTTornado WatchSPCAudrain, Callaway, Cape Girardeau, Crawford, Dent, Franklin and 18 more6 hr
May 21, 8:30 PM CDTTornado WatchSPCAdams, Buffalo, Butler, Chase, Clay, Custer and 31 more6 hr
May 22, 2:30 PM CDTSevere Thunderstorm WatchSPCBanner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 2 more7 hr

Nearby

Tornado Watches in Iowa, 1998Tornado Watches in Nebraska, 1998Tornado Watches in Missouri, 1998Every tornado watch 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; the sounding from the Mesonet's radiosonde archive.