Alert archive / Nebraska / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 625

August 20, 200218 counties in Nebraska; Bon Homme County, Yankton County, South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Aug 20, 2002, 6:55 PM CDT for 18 counties in Nebraska; Bon Homme County, Yankton County, South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 20, 2002, 6:55 PM CDT (23:55 UTC)
Expired
Aug 21, 2002, 1:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center

Counties Antelope County, NE, Blaine County, NE, Boyd County, NE, Brown County, NE, Cedar County, NE, Cherry County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keya Paha County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Thomas County, NE, Wheeler County, NE, Bon Homme County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 66 km from the middle of the area, began a volume at 23:56 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.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.9 hours before the alert went out and 141 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, N. Platte/Lee Bi, NE at 12:00Z on 2002-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 792 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, N. Platte/Lee Bi, NE at 12:00Z on 2002-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 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
792 J/kg
Mixed-layer CIN
-495 J/kg
Mixed-layer LCL
556 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 1:50 PM CDTSevere Thunderstorm WatchSPCArthur, Chase, Cherry, Cheyenne, Deuel, Dundy and 7 more5 hr
Aug 20, 2:35 PM CDTSevere Thunderstorm WatchSPCAurora, Beadle, Bennett, Brown, Brule, Buffalo and 29 more5 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2002Severe Thunderstorm Watches in South Dakota, 2002Every severe thunderstorm watch in 2002

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.