Alert archive / Nebraska / Mesoscale Discussions in 2021

Mesoscale Discussion 756

May 26, 20216 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 26, 2021, 5:48 PM MDT for 6 counties in Nebraska. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: May 26, 2021, 5:48 PM MDT (23:48 UTC)
Expired: May 26, 2021, 7:15 PM MDT
In force: 87 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 207

Counties Box Butte County, NE, Dawes County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE

The radar

The Cheyenne radar (KCYS), 178 km from the middle of the area, began a volume at 23:49 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

Rapid City, SD (KUNR), launched 12:00Z, 11.8 hours before the alert went out and 199 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 366 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

257 
ACUS11 KWNS 262348
SWOMCD
SPC MCD 262348 
NEZ000-SDZ000-WYZ000-270115-

Mesoscale Discussion 0756
NWS Storm Prediction Center Norman OK
0648 PM CDT Wed May 26 2021

Areas affected...Parts of the Nebraska Panhandle

Concerning...Severe Thunderstorm Watch 207...

Valid 262348Z - 270115Z

The severe weather threat for Severe Thunderstorm Watch 207
continues.

SUMMARY...Strong to severe thunderstorm development remains possible
northwest through west of Alliance, NE through around 7-8 PM MDT,
before beginning to diminish.  A new severe weather watch probably
will not be needed, but trends will continue to be monitored.

DISCUSSION...Moderate to strong boundary-layer instability remains
largely confined to a narrow corridor of stronger daytime heating,
within surface troughing to the lee of the Laramie Mountains into
western portions of the Nebraska Panhandle.  As a significant short
wave trough continues to progress across and east of the northern
Rockies into this evening, this environment could still support
additional strong/severe storm development, including a supercell or
two, another couple of hours.  However, toward 01-03Z, the southward
progression of a surface cold front, coupled with diurnal
boundary-layer cooling probably will result in the onset of
diminishing convective trends.

..Kerr.. 05/26/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LBF...UNR...CYS...

LAT...LON   42990299 42550221 42040210 41650287 41590398 41650458
            42310407 43000404 42990299

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 26, 9:14 AM MDT	Mesoscale Discussion	SPC	Dundy, Hitchcock, Red Willow	61 min
May 26, 11:45 AM MDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 5 more	2 hr
May 26, 1:27 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Box Butte, Cherry, Cheyenne, Dawes and 11 more	8 hr
May 26, 3:42 PM MDT	Tornado Watch PDS	SPC	Chase, Dundy, Frontier, Hayes, Hitchcock, Lincoln and 2 more	8 hr
May 26, 4:44 PM MDT	Mesoscale Discussion	SPC	Arthur, Chase, Cheyenne, Deuel, Dundy, Franklin and 13 more	2 hr
May 26, 5:07 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Blaine, Buffalo, Butler, Clay, Custer and 28 more	8 hr

Nearby

Mesoscale Discussions in Nebraska, 2021 Every mesoscale discussion in 2021

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.