Alert archive / Missouri / Mesoscale Discussions in 2021

Mesoscale Discussion 1829

October 11, 20217 counties in Arkansas; 8 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Oct 11, 2021, 1:26 AM CDT for 7 counties in Arkansas; 8 counties in Missouri. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Oct 11, 2021, 1:26 AM CDT (06:26 UTC)
Expired
Oct 11, 2021, 2:30 AM CDT
In force
64 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 519

Counties Benton County, AR, Carroll County, AR, Crawford County, AR, Franklin County, AR, Madison County, AR, Sebastian County, AR, Washington County, AR, Barry County, MO, Dade County, MO, Greene County, MO, Jasper County, MO, Lawrence County, MO, McDonald County, MO, Newton County, MO, Stone County, MO

The radar

The Springfield radar (KSGF), 115 km from the middle of the area, began a volume at 06:27 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

Springfield, MO (KSGF), launched 00:00Z, 6.4 hours before the alert went out and 66 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, Springfield, MO at 00:00Z on 2021-10-11Temperature 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, Springfield, MO at 00:00Z on 2021-10-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 square meters per square second.1939587897117Sfc1 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
2067 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
192 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

148 
ACUS11 KWNS 110627
SWOMCD
SPC MCD 110626 
MOZ000-ARZ000-110730-

Mesoscale Discussion 1829
NWS Storm Prediction Center Norman OK
0126 AM CDT Mon Oct 11 2021

Areas affected...Portions of northwestern AR and southwestern MO

Concerning...Tornado Watch 519...

Valid 110626Z - 110730Z

The severe weather threat for Tornado Watch 519 continues.

SUMMARY...An isolated severe threat may continue across mainly
southwestern Missouri in the short term, but downstream watch
issuance is not expected.

DISCUSSION...A line of storms that has recently moved from eastern
OK into western AR and southwestern MO has generally weakened as it
encounters a less unstable airmass. One exception has been with a
small segment across southwestern MO, where a low-level circulation
with corresponding CC minimum has been detected by the KSGF radar.
Clearly the low-level shear remains favorable for a brief embedded
tornado or two with this activity. But, the thermodynamic
environment downstream, with MLCAPE around 500 J/kg, appears only
marginally conducive for sustained severe convection. Tornado Watch
519 is currently scheduled to expire at 07Z (2 AM CDT). While a
small extension in time and area to WW 519 is possible across a
small part of southwestern MO downstream of the ongoing storms, the
overall severe threat is not expected to be great enough beyond the
next 1-2 hours to justify new downstream watch issuance.

..Gleason.. 10/11/2021

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

ATTN...WFO...LZK...SGF...TSA...

LAT...LON   35059438 35639442 36369451 37359453 37649411 37569337
            37139319 36119342 35409380 35059438

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 9:24 PM CDTTornado WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more5 hr
Oct 10, 10:16 PM CDTMesoscale DiscussionSPCLittle River, Polk, Sevier59 min
Oct 10, 11:07 PM CDTTornado WatchSPCHempstead, Howard, Lafayette, Little River, Logan, Miller and 6 more5 hr
Oct 10, 11:32 PM CDTMesoscale DiscussionSPCBenton, Crawford, Polk, Scott, Sebastian, Sevier and 1 more118 min
Oct 11, 12:58 AM CDTMesoscale DiscussionSPCHempstead, Howard, Lafayette, Little River, Logan, Miller and 5 more92 min
Oct 10, 7:19 PM CDTMesoscale DiscussionSPCBates86 min
Oct 11, 5:00 AM CDTMesoscale DiscussionSPCCedar, Christian, Dade, Dallas, Greene, Hickory and 7 more2 hr
Oct 11, 9:06 AM CDTMesoscale DiscussionSPCAudrain, Callaway, Franklin, Gasconade, Jefferson, Lincoln and 11 more2 hr

Nearby

Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Arkansas, 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.