Alert archive / Nebraska / Mesoscale Discussions in 2021

Mesoscale Discussion 1225

July 9, 20214 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2021, 9:44 PM MDT for 4 counties in Nebraska. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Jul 9, 2021, 9:44 PM MDT (03:44 UTC)
Expired: Jul 9, 2021, 11:15 PM MDT
In force: 91 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 361

Counties Box Butte County, NE, Garden County, NE, Grant County, NE, Sheridan County, NE

The radar

The North Platte radar (KLNX), 138 km from the middle of the area, began a volume at 03:46 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, 3.7 hours before the alert went out and 176 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: 2799 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1859 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.9

Open this sounding in Storm Lab

The text

As transmitted.

593 
ACUS11 KWNS 100344
SWOMCD
SPC MCD 100344 
NEZ000-100515-

Mesoscale Discussion 1225
NWS Storm Prediction Center Norman OK
1044 PM CDT Fri Jul 09 2021

Areas affected...northwest NE

Concerning...Severe Thunderstorm Watch 361...

Valid 100344Z - 100515Z

The severe weather threat for Severe Thunderstorm Watch 361
continues.

SUMMARY...An intense supercell cluster will likely transition to a
bow-shaped complex over the next 1 to 1.5 hours.  During this
relatively rare convective evolution, wind-driven large hail within
a focused corridor of potential severe gusts may occur.

DISCUSSION...An intense cluster of thunderstorms is quickly moving
southeast across the NE Panhandle this evening ahead of a shortwave
trough located over southeast MT/northeast WY.  Strong
west-northwesterly flow (50-60 kt) sampled between 4-8 km AGL atop
low-level easterlies was noted on the Thedford, NE 88D VAD.  The
strong shear/forcing will favor a continuation of organized severe
thunderstorms southeastward into west-central NE.  It seems
plausible wind-driven hail may accompany these storms as they move
southeast over the next 1 to 1.5 hours.  Severe gusts 60-75 mph and
large hail are the threats with this activity.

..Smith.. 07/10/2021

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

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

LAT...LON   42260154 41890155 41610172 41500215 42080341 42310293
            42710271 42600253 42260154

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 9, 7:21 PM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Arthur, Blaine, Boone, Boyd and 44 more	114 min
Jul 9, 7:45 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Antelope, Boone, Buffalo, Cedar, Clay and 28 more	8 hr
Jul 9, 8:06 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Blaine, Boyd, Brown, Cherry, Custer and 15 more	6 hr
Jul 9, 8:12 PM MDT	Mesoscale Discussion	SPC	Burt, Cass, Cuming, Dodge, Douglas, Gage and 13 more	2 hr
Jul 9, 8:58 PM MDT	Severe Thunderstorm Watch	SPC	Burt, Butler, Cass, Cuming, Dodge, Douglas and 14 more	7 hr
Jul 9, 9:20 PM MDT	Mesoscale Discussion	SPC	Butler, Clay, Fillmore, Gage, Hamilton, Jefferson and 7 more	115 min
Jul 10, 12:37 AM MDT	Mesoscale Discussion	SPC	Custer, Dawson, Lincoln, Logan, Thomas	53 min
Jul 10, 12:45 AM MDT	Mesoscale Discussion	SPC	Custer, Dawson, Lincoln, Logan, Thomas	60 min
Jul 10, 12:20 PM MDT	Mesoscale Discussion	SPC	Butler, Cass, Douglas, Fillmore, Gage, Jefferson and 12 more	115 min
Jul 10, 1:18 PM MDT	Severe Thunderstorm Watch	SPC	Cass, Douglas, Gage, Johnson, Lancaster, Nemaha and 4 more	7 hr
Jul 10, 2:44 PM MDT	Mesoscale Discussion	SPC	Gage, Johnson, Nemaha, Pawnee, Richardson	91 min
Jul 10, 4:27 PM MDT	Mesoscale Discussion	SPC	Richardson	2 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.