Alert archive / Kansas / Mesoscale Discussions in 2021

Mesoscale Discussion 1315

July 18, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2021, 1:32 PM MDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 18, 2021, 1:32 PM MDT (19:32 UTC)
Expired: Jul 18, 2021, 4:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 40 counties

Baca County, CO, Bent County, CO, Cheyenne County, CO, Kiowa County, CO, Prowers County, CO, Barber County, KS, Clark County, KS, Comanche County, KS, Edwards County, KS, Finney County, KS, Ford County, KS, Grant County, KS, Gray County, KS, Greeley County, KS, Hamilton County, KS, Haskell County, KS, Hodgeman County, KS, Kearny County, KS, Kiowa County, KS, Meade County, KS, Morton County, KS, Pawnee County, KS, Pratt County, KS, Seward County, KS, Stafford County, KS, Stanton County, KS, Stevens County, KS, Wallace County, KS, Wichita County, KS, Alfalfa County, OK, Beaver County, OK, Ellis County, OK, Harper County, OK, Major County, OK, Texas County, OK, Woods County, OK, Woodward County, OK, Hansford County, TX, Lipscomb County, TX, Ochiltree County, TX

The radar

The Dodge City radar (KDDC), 80 km from the middle of the area, began a volume at 19:35 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 383Jul 18, 4:10 PM MDT

The nearest sounding before it

Dodge City, (KDDC), launched 12:00Z, 7.5 hours before the alert went out and 86 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: 525 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1199 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

797 
ACUS11 KWNS 181933
SWOMCD
SPC MCD 181932 
KSZ000-OKZ000-TXZ000-COZ000-182200-

Mesoscale Discussion 1315
NWS Storm Prediction Center Norman OK
0232 PM CDT Sun Jul 18 2021

Areas affected...Portions of eastern CO...western/central KS...the
TX/OK Panhandles...and northwestern OK

Concerning...Severe potential...Watch possible 

Valid 181932Z - 182200Z

Probability of Watch Issuance...40 percent

SUMMARY...Some threat for large hail and severe wind gusts may
persist this afternoon with storms moving southward. The need for a
watch is uncertain, but watch issuance remains possible.

DISCUSSION...Storms have continued this afternoon across
western/central KS in association with a remnant MCV and related
mid-level perturbation evident in water vapor satellite imagery.
Even though low/mid-level flow remains fairly modest, upper-level
northwesterly winds do strengthen to around 35-45 kt. Multiple cells
that developed earlier along an outflow boundary across far western
KS in this regime have produced large hail up to 2 inches in
diameter. A separate small line segment in south-central KS recorded
a severe wind gust to 61 mph at 1915Z. Around 30-35 kt of effective
bulk shear present over far eastern CO into western/central KS and
vicinity should prove favorable for continued storm organization.
MLCAPE ranging from 1500-2000 J/kg across this region should also
sustain ongoing and new updrafts. There is some concern that ongoing
convection may grow upscale into one or more small bowing clusters
and pose a threat for isolated to scattered severe wind gusts as
they move southward across western KS, the OK/TX Panhandles, and
perhaps northwestern OK through the remainder of the afternoon.
Watch issuance is possible, and will largely be dependent on signs
of upscale growth into a cluster.

..Gleason/Dial.. 07/18/2021

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

ATTN...WFO...ICT...OUN...DDC...GLD...AMA...PUB...

LAT...LON   39000269 39040191 38680142 38280043 38209961 38389907
            38209847 36699812 36119856 35849950 35850088 36290170
            36950259 37730324 38510304 39000269

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 18, 10:14 AM MDT	Mesoscale Discussion	SPC	Barton, Decatur, Ellis, Gove, Graham, Hodgeman and 11 more	2 hr
Jul 18, 4:08 PM MDT	Severe Thunderstorm Watch	SPC	Beckham, Blaine, Caddo, Comanche, Custer, Dewey and 9 more	6 hr

Nearby

Mesoscale Discussions in Kansas, 2021 Mesoscale Discussions in Oklahoma, 2021 Mesoscale Discussions in Colorado, 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.