Alert archive / Missouri / Mesoscale Discussions in 2021

Mesoscale Discussion 1887

October 24, 2021Calhoun County, Greene County, Illinois; 30 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Oct 24, 2021, 2:13 AM CDT for Calhoun County, Greene County, Illinois; 30 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Oct 24, 2021, 2:13 AM CDT (07:13 UTC)
Expired
Oct 24, 2021, 4:15 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 530
All 32 counties

Calhoun County, IL, Greene County, IL, Andrew County, MO, Audrain County, MO, Boone County, MO, Buchanan County, MO, Caldwell County, MO, Callaway County, MO, Carroll County, MO, Chariton County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Howard County, MO, Lafayette County, MO, Lincoln County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Platte County, MO, Ralls County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Shelby County, MO

The radar

The Pleasant Hill radar (KEAX), 119 km from the middle of the area, began a volume at 07:14 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

Topeka, KS (KTOP), launched 00:00Z, 7.2 hours before the alert went out and 218 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, Topeka, KS at 00:00Z on 2021-10-24Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Topeka, KS at 00:00Z on 2021-10-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 339 square meters per square second.193958Sfc1 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
616 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
339 m²/s²
0-3 km storm-relative helicity
493 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

877 
ACUS11 KWNS 240713
SWOMCD
SPC MCD 240713 
MOZ000-ILZ000-KSZ000-240915-

Mesoscale Discussion 1887
NWS Storm Prediction Center Norman OK
0213 AM CDT Sun Oct 24 2021

Areas affected...Parts of northern and central Missouri and adjacent
portions of northeastern Kansas and west central Illinois

Concerning...Severe Thunderstorm Watch 530...

Valid 240713Z - 240915Z

The severe weather threat for Severe Thunderstorm Watch 530
continues.

SUMMARY...Increasing thunderstorm development appears likely in a
corridor across north central Missouri, to the north of Interstate
70, through 4-6 AM CDT.  Some of this activity may pose a risk for
severe hail, which may continue beyond the watch expiration. 
However, this threat may remain marginal enough that a new severe
weather watch may not be needed.

DISCUSSION...The primary initial convective development has been
focused along the warm frontal zone near the 850 mb level, beneath
the cooler mid-level temperatures.  To the south of this band,
potential instability is larger, but inhibition associated with
warmer mid-level temperatures has tended to suppress thunderstorm
development.  However, latest model output continues to indicate
that there will be increasing lift along this corridor through
09-11Z, which seems likely to support increasing new thunderstorm
development.  As this occurs, the environment will probably be
conducive to a few supercell structures posing at least a marginal
severe hail risk, before activity becomes more widespread.

..Kerr.. 10/24/2021

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

ATTN...WFO...LSX...EAX...

LAT...LON   40239522 40199266 39349033 38849074 38839255 38949395
            39229485 40239522

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 23, 9:14 PM CDTMesoscale DiscussionSPCAdams, Hancock3 hr
Oct 24, 12:40 PM CDTMesoscale DiscussionSPCCalhoun, Jersey3 hr
Oct 24, 2:06 PM CDTTornado WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Pike9 hr
Oct 24, 5:11 PM CDTMesoscale DiscussionSPCBond, Calhoun, Cass, Champaign, Christian, Clark and 39 more3 hr
Oct 24, 5:44 PM CDTTornado WatchSPCAlexander, Bond, Cass, Champaign, Christian, Clark and 47 more7 hr
Oct 23, 9:53 PM CDTSevere Thunderstorm WatchSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 24 more7 hr
Oct 24, 3:28 PM CDTMesoscale DiscussionSPCBates, Caldwell, Carroll, Cass, Daviess, Grundy and 10 more92 min
Oct 24, 3:50 PM CDTMesoscale DiscussionSPCAudrain, Callaway, Cole, Franklin, Gasconade, Lincoln and 8 more85 min
Oct 24, 5:25 PM CDTMesoscale DiscussionSPCAdair, Audrain, Benton, Boone, Callaway, Camden and 41 more2 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.