Alert archive / Missouri / Mesoscale Discussions in 2021

Mesoscale Discussion 1019

June 19, 202112 counties in Illinois; 14 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2021, 5:11 PM CDT for 12 counties in Illinois; 14 counties in Missouri. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Jun 19, 2021, 5:11 PM CDT (22:11 UTC)
Expired
Jun 19, 2021, 6:15 PM CDT
In force
64 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 287
All 26 counties

Calhoun County, IL, Clinton County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Monroe County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Scott County, IL, Washington County, IL, Audrain County, MO, City of Saint Louis, MO, Franklin County, MO, Jefferson County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Shelby County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 32 km from the middle of the area, began a volume at 22:11 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

Lincoln, IL (KILX), launched 12:00Z, 10.2 hours before the alert went out and 224 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, Lincoln, IL at 12:00Z on 2021-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Lincoln, IL at 12:00Z on 2021-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 142 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1960 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
142 m²/s²
0-3 km storm-relative helicity
203 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

635 
ACUS11 KWNS 192211
SWOMCD
SPC MCD 192211 
ILZ000-MOZ000-192315-

Mesoscale Discussion 1019
NWS Storm Prediction Center Norman OK
0511 PM CDT Sat Jun 19 2021

Areas affected...eastern MO...western IL

Concerning...Severe Thunderstorm Watch 287...

Valid 192211Z - 192315Z

The severe weather threat for Severe Thunderstorm Watch 287
continues.

SUMMARY...Large hail and damaging winds continues to be possible
with storms across the watch area.

DISCUSSION...A cluster of severe storms was in progress in the St.
Louis area at 2210z, with a history of damaging winds and severe
hail.  New development was occurring upstream in the vicinity of
Hannibal, MO, where upwards of 4000 J/kg of MLCAPE is present.  The
region is on the southern periphery of stronger mid-level flow, and
35-40 kts of northwesterly effective shear will continue to be
conducive for supercells with a wind and hail threat. Where
additional storm mergers occur, a more concentrated damaging wind
risk will be possible with southward moving clusters.

..Bunting.. 06/19/2021

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

ATTN...WFO...PAH...ILX...LSX...

LAT...LON   37958976 38259084 38729161 38909179 39559224 40009224
            39939144 39789066 39288972 39018958 38508921 37958976

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 18, 8:53 PM CDTMesoscale DiscussionSPCBond, Brown, Cass, Christian, Clark, Clay and 26 more97 min
Jun 18, 9:20 PM CDTSevere Thunderstorm WatchSPCCass, Champaign, Christian, Clark, Clay, Coles and 33 more7 hr
Jun 18, 9:27 PM CDTMesoscale DiscussionSPCAdams, Brown, Hancock, Henderson, McDonough, Mercer and 2 more2 hr
Jun 18, 10:08 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Bureau, Hancock, Henderson, Henry and 6 more8 hr
Jun 19, 2:10 AM CDTMesoscale DiscussionSPCAdams, Brown, Cass, Champaign, Christian, Clark and 27 more2 hr
Jun 19, 11:15 AM CDTMesoscale DiscussionSPCEffingham, Fayette, Greene, Macoupin, Montgomery, Morgan and 1 more2 hr
Jun 19, 2:12 PM CDTMesoscale DiscussionSPCBond, Calhoun, Clinton, Greene, Jersey, Macoupin and 7 more93 min
Jun 19, 2:43 PM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Clinton, Fayette, Greene, Jersey and 9 more7 hr

Nearby

Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Illinois, 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.