Alert archive / Kansas / Mesoscale Discussions in 2021

Mesoscale Discussion 317

April 6, 202120 counties in Kansas; 14 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2021, 7:10 PM CDT for 20 counties in Kansas; 14 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 6, 2021, 7:10 PM CDT (00:10 UTC)
Expired: Apr 6, 2021, 9:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 72

All 34 counties

Barton County, KS, Edwards County, KS, Ellis County, KS, Ellsworth County, KS, Jewell County, KS, Kingman County, KS, Kiowa County, KS, Lincoln County, KS, Mitchell County, KS, Osborne County, KS, Pawnee County, KS, Phillips County, KS, Pratt County, KS, Reno County, KS, Rice County, KS, Rooks County, KS, Rush County, KS, Russell County, KS, Smith County, KS, Stafford County, KS, Adams County, NE, Buffalo County, NE, Clay County, NE, Franklin County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Merrick County, NE, Nuckolls County, NE, Phelps County, NE, Sherman County, NE, Webster County, NE

The radar

The Grand Island radar (KUEX), 154 km from the middle of the area, began a volume at 00:09 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

Dodge City, (KDDC), launched 00:00Z, 0.2 hours before the alert went out and 160 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: 71 J/kg
Mixed-layer CIN: -135 J/kg
Mixed-layer LCL: 3516 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 234 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

479 
ACUS11 KWNS 070010
SWOMCD
SPC MCD 070010 
KSZ000-NEZ000-070215-

Mesoscale Discussion 0317
NWS Storm Prediction Center Norman OK
0710 PM CDT Tue Apr 06 2021

Areas affected...Parts of Kansas and south-central Nebraska

Concerning...Severe Thunderstorm Watch 72...

Valid 070010Z - 070215Z

The severe weather threat for Severe Thunderstorm Watch 72
continues.

SUMMARY...Severe threat continues across ww72.

DISCUSSION...Large-scale forcing for ascent is spreading across the
central High Plains this evening, per expanding cloud shield over
eastern CO into far western KS. Over the next several hours it
appears the frontal zone should sharpen and surge southeast across
ww72. Convection is gradually solidifying along the wind shift and a
forced line may ultimately evolve as the front begins to surge. Hail
remains the primary risk, though damaging winds are also possible.
The primary supercell risk is along the southern flank of this
developing squall line where a tornado can not be ruled out over the
next few hours.

..Darrow.. 04/07/2021

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

ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD...

LAT...LON   37489963 41269959 41279786 37489798 37489963

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 6, 9:06 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Chase, Clay, Cloud, Coffey, Dickinson and 22 more	5 hr
Apr 6, 9:11 PM CDT	Mesoscale Discussion	SPC	Barton, Clay, Cloud, Dickinson, Ellsworth, Geary and 8 more	2 hr
Apr 6, 11:22 PM CDT	Mesoscale Discussion	SPC	Chase, Harvey, Kingman, Lyon, McPherson, Marion and 3 more	113 min
Apr 7, 10:18 AM CDT	Mesoscale Discussion	SPC	Johnson, Miami, Wyandotte	117 min

Nearby

Mesoscale Discussions in Kansas, 2021 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.