Alert archive / Missouri / Mesoscale Discussions in 2021
Mesoscale Discussion 1891
The Storm Prediction Center issued this mesoscale discussion at Oct 24, 2021, 3:50 PM CDT for 14 counties in Missouri. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Oct 24, 2021, 3:50 PM CDT (20:50 UTC)
- Expired
- Oct 24, 2021, 5:15 PM CDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 531
Counties Audrain County, MO, Callaway County, MO, Cole County, MO, Franklin County, MO, Gasconade County, MO, Lincoln County, MO, Maries County, MO, Montgomery County, MO, Osage County, MO, Phelps County, MO, Pike County, MO, Pulaski County, MO, Ralls County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 83 km from the middle of the area, began a volume at 20:50 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 12:00Z, 8.8 hours before the alert went out and 270 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.
- Mixed-layer CAPE
- 860 J/kg
- Mixed-layer CIN
- -152 J/kg
- Mixed-layer LCL
- 737 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 225 m²/s²
- 0-3 km storm-relative helicity
- 70 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
874
ACUS11 KWNS 242050
SWOMCD
SPC MCD 242050
MOZ000-242215-
Mesoscale Discussion 1891
NWS Storm Prediction Center Norman OK
0350 PM CDT Sun Oct 24 2021
Areas affected...Portions of central/eastern MO
Concerning...Tornado Watch 531...
Valid 242050Z - 242215Z
The severe weather threat for Tornado Watch 531 continues.
SUMMARY...The severe threat, including the potential for tornadoes,
will probably increase over the next couple of hours across parts of
central and eastern Missouri.
DISCUSSION...A pre-frontal line of storms has recently strengthened
from parts of central into northeastern MO. Even with persistent
cloud cover, the airmass downstream is gradually destabilizing as a
surface warm front lifts northward, with MLCAPE generally in the
1000-1500 J/kg range. A 20Z sounding from the University of Missouri
in Columbia shows a strongly veering and strengthening wind profile
with height from the surface through mid levels, with over 350 m2/s2
of effective SRH present. 40-50 kt of effective bulk shear will be
favorable for sustained supercells. The current, more linear
convection may be slightly elevated at the moment based on recent
radar trends. If any supercell can evolve from this activity, or if
new discrete storm development occurs farther south into central MO,
then the tornado threat would likely increase given the very
favorable low-level shear present.
..Gleason.. 10/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LSX...SGF...
LAT...LON 39249080 38919076 38419106 37809163 37469226 37449244
37849250 38689232 39319197 39559174 39659135 39249080SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 23, 9:14 PM CDT | Mesoscale Discussion | SPC | Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 26 more | 3 hr |
| Oct 23, 9:53 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 24 more | 7 hr |
| Oct 24, 2:13 AM CDT | Mesoscale Discussion | SPC | Andrew, Audrain, Boone, Buchanan, Caldwell, Callaway and 24 more | 2 hr |
| Oct 24, 12:40 PM CDT | Mesoscale Discussion | SPC | Audrain, Barry, Barton, Benton, Boone, Callaway and 60 more | 3 hr |
| Oct 24, 2:06 PM CDT | Tornado Watch | SPC | Adair, Andrew, Audrain, Barry, Barton, Bates and 83 more | 9 hr |
| Oct 24, 3:28 PM CDT | Mesoscale Discussion | SPC | Bates, Caldwell, Carroll, Cass, Daviess, Grundy and 10 more | 92 min |
| Oct 24, 5:11 PM CDT | Mesoscale Discussion | SPC | Saint Louis, City of Saint Louis | 3 hr |
| Oct 24, 5:25 PM CDT | Mesoscale Discussion | SPC | Adair, Audrain, Benton, Boone, Callaway, Camden and 41 more | 2 hr |
| Oct 24, 5:44 PM CDT | Tornado Watch | SPC | Bollinger, Butler, Cape Girardeau, Carter, Madison, Mississippi and 8 more | 7 hr |
Nearby
Mesoscale Discussions in Missouri, 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.