Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 1486

August 12, 201710 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2017, 8:41 PM CDT for 10 counties in Nebraska. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Aug 12, 2017, 8:41 PM CDT (01:41 UTC)
Expired
Aug 12, 2017, 10:15 PM CDT
In force
94 min
Issued by
the Storm Prediction Center

Counties Buffalo County, NE, Custer County, NE, Dawson County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Phelps County, NE, Red Willow County, NE, Sherman County, NE, Valley County, NE

The radar

The Grand Island radar (KUEX), 144 km from the middle of the area, began a volume at 01:41 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, 1.7 hours before the alert went out and 65 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 2017-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 815 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 2017-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 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
815 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
1218 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
240 m²/s²
Significant tornado parameter
0.5
Supercell composite
6.6

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
Aug 13, 3:18 PM CDTMesoscale DiscussionSPCBlaine, Boyd, Brown, Buffalo, Custer, Dawson and 22 more117 min
Aug 13, 4:00 PM CDTSevere Thunderstorm WatchSPCAntelope, Blaine, Boone, Boyd, Brown, Buffalo and 35 more11 hr

Nearby

Mesoscale Discussions in Nebraska, 2017Every mesoscale discussion in 2017

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.