Alert archive / Nebraska / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 227

May 20, 2004Phillips County, Sedgwick County, Yuma County, Colorado; 38 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at May 20, 2004, 9:30 PM MDT for Phillips County, Sedgwick County, Yuma County, Colorado; 38 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: May 20, 2004, 9:30 PM MDT (03:30 UTC)
Expired: May 21, 2004, 3:00 AM MDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 41 counties

Phillips County, CO, Sedgwick County, CO, Yuma County, CO, Adams County, NE, Buffalo County, NE, Butler County, NE, Chase County, NE, Clay County, NE, Colfax County, NE, Custer County, NE, Dawson County, NE, Deuel County, NE, Dundy County, NE, Fillmore County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Hayes County, NE, Hitchcock County, NE, Howard County, NE, Jefferson County, NE, Kearney County, NE, Keith County, NE, Lincoln County, NE, Merrick County, NE, Nance County, NE, Nuckolls County, NE, Perkins County, NE, Phelps County, NE, Polk County, NE, Red Willow County, NE, Saline County, NE, Seward County, NE, Sherman County, NE, Thayer County, NE, Webster County, NE, York County, NE

The radar

The North Platte radar (KLNX), 127 km from the middle of the area, began a volume at 03:32 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

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

Issued	Product	Office	Counties	Lasted
May 20, 11:24 PM MDT	Severe Thunderstorm Warning	OAX	Colfax	21 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 3.5 hours before the alert went out and 36 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: 49 J/kg
Mixed-layer CIN: -385 J/kg
Mixed-layer LCL: 1444 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: -31 m²/s²
0-3 km storm-relative helicity: 215 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.

Issued	Product	Office	Counties	Lasted
May 20, 6:15 PM MDT	Tornado Watch	SPC	Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 9 more	5 hr
May 20, 9:03 PM MDT	Mesoscale Discussion	SPC	Cheyenne, Kit Carson, Phillips, Yuma	87 min
May 20, 9:04 PM MDT	Mesoscale Discussion	SPC	Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 9 more	86 min
May 21, 12:11 AM MDT	Mesoscale Discussion	SPC	Antelope, Arthur, Blaine, Boone, Boyd, Brown and 29 more	34 min
May 21, 12:20 AM MDT	Severe Thunderstorm Watch	SPC	Antelope, Boone, Boyd, Burt, Cedar, Colfax and 18 more	6 hr
May 21, 1:22 AM MDT	Mesoscale Discussion	SPC	Antelope, Boone, Boyd, Burt, Cedar, Cuming and 11 more	23 min
May 21, 1:22 PM MDT	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 3 more	113 min
May 21, 2:05 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 8 more	5 hr
May 21, 3:57 PM MDT	Mesoscale Discussion	SPC	Blaine, Brown, Cherry, Hooker, Keya Paha, Logan and 2 more	93 min
May 21, 4:35 PM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Boone, Buffalo, Burt, Butler and 35 more	115 min
May 21, 5:33 PM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Boone, Boyd, Buffalo, Burt and 44 more	57 min

Nearby

Severe Thunderstorm Watches in Nebraska, 2004 Severe Thunderstorm Watches in Colorado, 2004 Every severe thunderstorm watch in 2004

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.