Alert archive / Nebraska / Severe Thunderstorm Watches in 2003

Severe Thunderstorm Watch 127

April 18, 20038 counties in Iowa; 19 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Apr 18, 2003, 6:20 PM CDT for 8 counties in Iowa; 19 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2003, 6:20 PM CDT (23:20 UTC)
Expired
Apr 19, 2003, 12:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 27 counties

Crawford County, IA, Harrison County, IA, Ida County, IA, Monona County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Woodbury County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Knox County, NE, Madison County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE

The radar

The Omaha radar (KOAX), 104 km from the middle of the area, began a volume at 23:23 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.

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 18, 6:50 PM CDTSevere Thunderstorm WarningOAXAntelope, Boone40 min
Apr 18, 8:03 PM CDTSevere Thunderstorm WarningOAXColfax, Platte42 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.3 hours before the alert went out and 104 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 2003-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2003-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
637 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
120 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
Apr 18, 3:50 PM CDTTornado WatchSPCFremont, Mills6 hr
Apr 18, 5:15 PM CDTMesoscale DiscussionSPCFremont90 min
Apr 18, 2:52 PM CDTMesoscale DiscussionSPCPawnee113 min

Nearby

Severe Thunderstorm Watches in Nebraska, 2003Severe Thunderstorm Watches in Iowa, 2003Every severe thunderstorm watch in 2003

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.