Alert archive / Nebraska / Mesoscale Discussions in 2021

Mesoscale Discussion 443

April 27, 20218 counties in Kansas; 9 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2021, 9:31 PM CDT for 8 counties in Kansas; 9 counties in Nebraska. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Apr 27, 2021, 9:31 PM CDT (02:31 UTC)
Expired: Apr 27, 2021, 10:30 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 114

Counties Cheyenne County, KS, Decatur County, KS, Graham County, KS, Norton County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Chase County, NE, Dawson County, NE, Dundy County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Hayes County, NE, Hitchcock County, NE, Red Willow County, NE

The radar

The Goodland radar (KGLD), 99 km from the middle of the area, began a volume at 02:34 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, 2.5 hours before the alert went out and 130 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: 14 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 1209 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 212 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

080 
ACUS11 KWNS 280231
SWOMCD
SPC MCD 280231 
KSZ000-NEZ000-280330-

Mesoscale Discussion 0443
NWS Storm Prediction Center Norman OK
0931 PM CDT Tue Apr 27 2021

Areas affected...Northwest Kansas and Southwest Nebraska

Concerning...Severe Thunderstorm Watch 114...

Valid 280231Z - 280330Z

The severe weather threat for Severe Thunderstorm Watch 114
continues.

SUMMARY...A gradual weakening trend is noted in the line of storms
moving across northeast Kansas. However, severe hail and wind will
remain possible for the next few hours across Watch 114.

DISCUSSION...A convective line continues to move to the
east/northeast across northwest KS and into far southwest NE.
Several severe wind and hail reports have been noted with this line,
and MRMS echo tops show stronger embedded pulses that will continue
to pose a hail threat in the near term. Additionally, the strong
low-level shear (around 40-50 knots of 0-3 km bulk shear per RAP
mesoanalysis) oriented nearly orthogonal to the cold pool will
continue to support a damaging wind risk. However, IR trends over
the past hour have shown a gradual warming trend in cloud top
temperatures, suggesting that the overall intensity of the line may
be waning as it migrates towards the northern fringe of the more
favorable instability and towards a more capped environment. In
general, this trend is expected to continue over the next few hours
and the severe risk will likely become confined to stronger impulses
embedded within the line - most likely along the KS/NE state line
where the instability/shear parameter space will remain most
favorable for organized convection.

..Moore.. 04/28/2021

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

ATTN...WFO...GID...LBF...GLD...

LAT...LON   39360197 40000204 40500197 40940125 41090018 40859948
            40249952 39699957 39249991 39220073 39230162 39360197

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 27, 7:16 PM CDT	Mesoscale Discussion	SPC	Cheyenne, Decatur, Rawlins, Sherman, Thomas	119 min

Nearby

Mesoscale Discussions in Nebraska, 2021 Mesoscale Discussions in Kansas, 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.