Alert archive / Nebraska / Mesoscale Discussions in 2018

Mesoscale Discussion 447

May 17, 2018Logan County, Phillips County, Sedgwick County, Colorado; 15 counties in Nebraska; Bennett County, Fall River County, Oglala Lakota County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 17, 2018, 6:47 PM MDT for Logan County, Phillips County, Sedgwick County, Colorado; 15 counties in Nebraska; Bennett County, Fall River County, Oglala Lakota County, South Dakota. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued
May 17, 2018, 6:47 PM MDT (00:47 UTC)
Expired
May 17, 2018, 7:45 PM MDT
In force
58 min
Issued by
the Storm Prediction Center
All 21 counties

Logan County, CO, Phillips County, CO, Sedgwick County, CO, Arthur County, NE, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Keith County, NE, Kimball County, NE, Morrill County, NE, Perkins County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Bennett County, SD, Fall River County, SD, Oglala Lakota County, SD

The radar

The North Platte radar (KLNX), 187 km from the middle of the area, began a volume at 00:48 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 00:00Z, 0.8 hours before the alert went out and 224 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 00:00Z on 2018-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1242 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 00:00Z on 2018-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
1242 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
2392 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.7

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 17, 9:03 PM MDTMesoscale DiscussionSPCSedgwick117 min
May 18, 1:43 PM MDTMesoscale DiscussionSPCBaca, Bent, Kiowa, Prowers2 hr
May 18, 3:02 PM MDTSevere Thunderstorm WatchSPCBaca, Bent, Cheyenne, Crowley, El Paso, Huerfano and 6 more7 hr
May 18, 3:06 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Denver, Jefferson and 4 more114 min
May 18, 1:50 PM MDTMesoscale DiscussionSPCScotts Bluff, Sioux115 min
May 18, 5:04 PM MDTMesoscale DiscussionSPCBanner, Box Butte, Dawes, Morrill, Scotts Bluff, Sioux86 min
May 18, 5:27 PM MDTMesoscale DiscussionSPCDundy, Hitchcock, Red Willow63 min
May 17, 7:11 PM MDTMesoscale DiscussionSPCBennett, Buffalo, Dewey, Edmunds, Fall River, Faulk and 17 more64 min

Nearby

Mesoscale Discussions in Nebraska, 2018Mesoscale Discussions in Colorado, 2018Mesoscale Discussions in South Dakota, 2018Every mesoscale discussion in 2018

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.