Mesoscale Discussion 821

Issued

Jun 22, 2018, 11:31 AM MDT (17:31 UTC)

Expired

Jun 22, 2018, 1:00 PM MDT

In force

89 min

Issued by

the Storm Prediction Center

Chance of a watch

80%

Counties Baca County, CO, Bent County, CO, Cheyenne County, CO, Crowley County, CO, Elbert County, CO, Kiowa County, CO, Kit Carson County, CO, Lincoln County, CO, Otero County, CO, Prowers County, CO, Pueblo County, CO, Grant County, KS, Greeley County, KS, Hamilton County, KS, Kearny County, KS, Sherman County, KS, Stanton County, KS, Wallace County, KS, Wichita County, KS

The Pueblo radar (KPUX), 130 km from the middle of the area, began a volume at 17:33 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.

• Severe Thunderstorm Watch 198Jun 22, 12:15 PM MDT
• Severe Thunderstorm Watch 200Jun 22, 3:30 PM MDT

461 
ACUS11 KWNS 221731
SWOMCD
SPC MCD 221731 
KSZ000-COZ000-221900-

Mesoscale Discussion 0821
NWS Storm Prediction Center Norman OK
1231 PM CDT Fri Jun 22 2018

Areas affected...Portions of the Colorado and Kansas High Plains

Concerning...Severe potential...Watch likely 

Valid 221731Z - 221900Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms will increase in coverage this afternoon and
intensify as they move east away from higher terrain. Scattered
storms will likely be accompanied by large hail (a few possibly 2+"
in diameter), damaging winds, and perhaps a tornado or two. Watch
issuance will likely be needed by about 19Z.

DISCUSSION...Mid-level forcing for ascent is advancing across the
Colorado Front Range early this afternoon, already yielding strong
thunderstorms to the east of the Denver Metro. These storms have
developed prior to peak heating/destabilization, such that remaining
surface-based inhibition is likely stunting their development some.
Still, outflow-driven propagation may maintain a few strong cells as
this cluster approaches the eastern Colorado border and the boundary
layer continues to destabilize.

Farther south, ascent trailing to the south/southwest with the
mid-level impulse is expected to encourage new development south of
the Palmer Divide. Moist upslope flow and plentiful insolation
should yield moderate buoyancy (e.g., MLCAPE near 1500-2500 J/kg)
this afternoon over the High Plains. As storms encounter this
environment, sufficient effective shear and steep lapse rates should
support supercells capable of very large hail, damaging winds, and
perhaps a tornado or two. Strong outflow will likely drive an
evolution towards upscale growth (with a primarily damaging wind
threat) as cells head towards western Kansas late this afternoon
into the evening. Considering the threat, a watch will likely be
needed by about 19Z.

..Picca/Thompson.. 06/22/2018

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

ATTN...WFO...DDC...GLD...PUB...BOU...

LAT...LON   38250114 37560122 37250150 37170251 37170365 37500443
            37970464 39620435 39990381 39920225 39600167 38250114

Mesoscale Discussions in Colorado, 2018Mesoscale Discussions in Kansas, 2018Every mesoscale discussion in 2018

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.