Alert archive / Nebraska / Mesoscale Discussions in 2021

Mesoscale Discussion 1302

July 16, 20216 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 16, 2021, 9:17 PM MDT for 6 counties in Nebraska. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Jul 16, 2021, 9:17 PM MDT (03:17 UTC)
Expired
Jul 16, 2021, 10:45 PM MDT
In force
88 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 381

Counties Arthur County, NE, Cherry County, NE, Grant County, NE, Hooker County, NE, McPherson County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 66 km from the middle of the area, began a volume at 03:19 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, 3.3 hours before the alert went out and 120 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 2021-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 989 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 2021-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 square meters per square second.193958Sfc1 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
989 J/kg
Mixed-layer CIN
-136 J/kg
Mixed-layer LCL
1785 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
157 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

As transmitted.

763 
ACUS11 KWNS 170318
SWOMCD
SPC MCD 170317 
NEZ000-SDZ000-170445-

Mesoscale Discussion 1302
NWS Storm Prediction Center Norman OK
1017 PM CDT Fri Jul 16 2021

Areas affected...Northwestern Nebraska

Concerning...Severe Thunderstorm Watch 381...

Valid 170317Z - 170445Z

The severe weather threat for Severe Thunderstorm Watch 381
continues.

SUMMARY...Severe wind and hail threat will spread across Cherry
County Nebraska into the southeastern portions of ww381 over the
next few hours.

DISCUSSION...Mature MCS has evolved along the southwestern
SD/northwestern NE border. Leading edge of this MCS is surging
southeast at roughly 35kt across Cherry County NE. Given the
expanding precipitation shield, and cold pool that has formed, it
appears the leading edge of this complex may approach the
southeastern edge of ww381 by 05z. Damaging winds and large hail
continue to be a threat.

..Darrow.. 07/17/2021

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

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

LAT...LON   42070234 42340134 43210035 41890023 41300090 41450205
            42070234

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 16, 6:16 PM MDTMesoscale DiscussionSPCDawes89 min
Jul 17, 2:40 PM MDTMesoscale DiscussionSPCBanner, Box Butte, Cheyenne, Dawes, Deuel, Garden and 5 more3 hr

Nearby

Mesoscale Discussions in Nebraska, 2021Every 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.