Alert archive / Kansas / Mesoscale Discussions in 2021

Mesoscale Discussion 1221

July 9, 2021Cheyenne County, Kit Carson County, Washington County, Colorado; 10 counties in Kansas

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2021, 7:49 PM MDT for Cheyenne County, Kit Carson County, Washington County, Colorado; 10 counties in Kansas. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Jul 9, 2021, 7:49 PM MDT (01:49 UTC)
Expired
Jul 9, 2021, 9:15 PM MDT
In force
86 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 356

Counties Cheyenne County, CO, Kit Carson County, CO, Washington County, CO, Gove County, KS, Greeley County, KS, Hamilton County, KS, Kearny County, KS, Lane County, KS, Logan County, KS, Scott County, KS, Sherman County, KS, Wallace County, KS, Wichita County, KS

The radar

The Goodland radar (KGLD), 62 km from the middle of the area, began a volume at 01:51 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.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 1.8 hours before the alert went out and 147 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, Denver, CO at 00:00Z on 2021-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 807 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2021-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 square meters per square second.19395878Sfc1 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
807 J/kg
Mixed-layer CIN
-117 J/kg
Mixed-layer LCL
3619 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
173 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

021 
ACUS11 KWNS 100149
SWOMCD
SPC MCD 100149 
KSZ000-COZ000-100315-

Mesoscale Discussion 1221
NWS Storm Prediction Center Norman OK
0849 PM CDT Fri Jul 09 2021

Areas affected...East-central Colorado...west-central Kansas

Concerning...Severe Thunderstorm Watch 356...

Valid 100149Z - 100315Z

The severe weather threat for Severe Thunderstorm Watch 356
continues.

SUMMARY...A cluster of storms in east-central Colorado will move
into a more favorable environment for severe wind gusts and isolated
large hail. As this threat may persist beyond 10 PM CDT, a new WW
may be needed for parts of far eastern Colorado into western Kansas.
Trends will be monitored.

DISCUSSION...A small cluster of thunderstorms has recently developed
in east-central Colorado. As they move southeastward, they will
encounter low 60s F dewpoints with MLCAPE nearing 1500-2000 J/kg.
Given the dewpoint spreads at the surface, storms are likely to be
outflow dominant and primary pose a severe wind gust risk. However,
regional RAOBs this evening did sample very steep mid-level lapse
rates and long hodographs (40-50 kts of effective shear) will
promote at least an isolated large hail threat as well. The main
question will be how far south and east this activity will go as
MLCIN will become more pronounced. The longevity of these storms
will hinge on the degree of cold pool organization that can occur in
the next hour or so. That being said, some severe risk may extend
beyond 10 PM CDT for areas still in or just south of WW 356. A new
watch may need to be considered should convective trends warrant.

..Wendt.. 07/10/2021

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

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

LAT...LON   39400364 39810377 40060336 39770251 39190068 38770003
            38260031 37960099 37880160 37870198 38290242 39400364

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 9, 8:37 PM MDTSevere Thunderstorm WatchSPCCheyenne, Kiowa, Kit Carson, Prowers4 hr
Jul 9, 10:39 PM MDTMesoscale DiscussionSPCProwers66 min
Jul 9, 7:45 PM MDTSevere Thunderstorm WatchSPCJewell, Mitchell, Osborne, Phillips, Rooks, Smith8 hr
Jul 9, 8:12 PM MDTMesoscale DiscussionSPCAtchison, Brown, Clay, Cloud, Doniphan, Jackson and 9 more2 hr
Jul 9, 8:58 PM MDTSevere Thunderstorm WatchSPCAnderson, Atchison, Brown, Clay, Cloud, Coffey and 22 more7 hr
Jul 10, 12:10 AM MDTMesoscale DiscussionSPCEdwards, Finney, Ford, Grant, Gray, Hamilton and 10 more65 min
Jul 10, 12:21 AM MDTMesoscale DiscussionSPCAtchison, Brown, Doniphan, Jackson, Jefferson, Leavenworth and 2 more84 min
Jul 10, 1:57 AM MDTMesoscale DiscussionSPCAnderson, Clay, Cloud, Coffey, Dickinson, Douglas and 16 more93 min
Jul 10, 12:20 PM MDTMesoscale DiscussionSPCAtchison, Brown, Doniphan, Marshall, Nemaha, Washington115 min
Jul 10, 1:17 PM MDTMesoscale DiscussionSPCAllen, Bourbon, Butler, Chautauqua, Cherokee, Cowley and 11 more118 min
Jul 10, 1:18 PM MDTSevere Thunderstorm WatchSPCAtchison, Brown, Doniphan, Douglas, Geary, Jackson and 10 more7 hr
Jul 10, 2:02 PM MDTSevere Thunderstorm WatchSPCAllen, Bourbon, Butler, Chautauqua, Cherokee, Cowley and 9 more8 hr
Jul 10, 4:27 PM MDTMesoscale DiscussionSPCAtchison, Brown, Doniphan, Douglas, Jackson, Jefferson and 9 more2 hr

Nearby

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