Alert archive / Missouri / Mesoscale Discussions in 2021
Mesoscale Discussion 325
The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2021, 3:13 PM CDT for 27 counties in Missouri. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Apr 7, 2021, 3:13 PM CDT (20:13 UTC)
- Expired
- Apr 7, 2021, 4:45 PM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 74
All 27 counties
Audrain County, MO, Boone County, MO, Callaway County, MO, Cole County, MO, Crawford County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Howard County, MO, Howell County, MO, Lincoln County, MO, Maries County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Phelps County, MO, Pike County, MO, Pulaski County, MO, Ralls County, MO, Randolph County, MO, Shannon County, MO, Shelby County, MO, Texas County, MO, Warren County, MO, Wright County, MO
The radar
The St Louis radar (KLSX), 129 km from the middle of the area, began a volume at 20:17 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, 8.2 hours before the alert went out and 217 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
- 790 J/kg
- Mixed-layer CIN
- -275 J/kg
- Mixed-layer LCL
- 767 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 186 m²/s²
- 0-3 km storm-relative helicity
- 223 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
418
ACUS11 KWNS 072013
SWOMCD
SPC MCD 072013
MOZ000-ILZ000-072145-
Mesoscale Discussion 0325
NWS Storm Prediction Center Norman OK
0313 PM CDT Wed Apr 07 2021
Areas affected...Parts of south central through northeastern
Missouri
Concerning...Severe Thunderstorm Watch 74...
Valid 072013Z - 072145Z
The severe weather threat for Severe Thunderstorm Watch 74
continues.
SUMMARY...An evolving squall line will pose a risk for potentially
damaging wind gusts and/or a couple of tornadoes across much of
south central and central into northeastern Missouri through 5-6 PM
CDT. It is not clear that a new severe weather watch will be needed
to the east of the watch, but trends are being monitored for this
possibility.
DISCUSSION...Despite thick low cloud cover in advance of the
evolving squall line, inflow still appears characterized by CAPE on
the order of 1000 J/kg, supporting a continued gradual
intensification and organization, in the presence of moderate to
strong vertical shear. As the vigorous upstream short wave trough
takes on an increasing negative tilt, deep-layer mean flow is
backing from southwesterly to southerly across much of Missouri.
This is expected to contribute to a north-northeastward development
of strongest convection across and north-northeast of the
Columbia/Jefferson City areas through 22-23Z, with activity probably
remaining to the west and northwest of much of the St. Louis area.
East of the West Plains and Vichy vicinities, warmer but somewhat
drier and less unstable boundary-layer air lingers. The extent to
which it will moisten and destabilize prior to the arrival of the
squall line and/or eastward surging cold front remains unclear.
..Kerr.. 04/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LSX...SGF...EAX...
LAT...LON 39319287 39859202 39049063 38349111 36729124 36669230
37079252 38009248 38569270 39319287SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 7, 6:40 AM CDT | Mesoscale Discussion | SPC | Barry, Camden, Cedar, Christian, Cole, Dade and 20 more | 2 hr |
| Apr 7, 10:18 AM CDT | Mesoscale Discussion | SPC | Barry, Barton, Bates, Benton, Boone, Buchanan and 42 more | 117 min |
| Apr 7, 12:02 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Audrain, Barry, Benton, Boone, Caldwell and 78 more | 7 hr |
| Apr 7, 1:30 PM CDT | Mesoscale Discussion | SPC | Camden, Christian, Cole, Dallas, Douglas, Greene and 13 more | 90 min |
| Apr 7, 2:22 PM CDT | Mesoscale Discussion | SPC | Howell, Oregon, Ozark, Stone, Taney | 53 min |
| Apr 7, 3:40 PM CDT | Mesoscale Discussion | SPC | Ozark | 65 min |
| Apr 7, 5:04 PM CDT | Mesoscale Discussion | SPC | Adair, Audrain, Callaway, Clark, Franklin, Gasconade and 17 more | 116 min |
| Apr 7, 5:12 PM CDT | Mesoscale Discussion | SPC | Dunklin, Pemiscot | 2 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.