Alert archive / Missouri / Mesoscale Discussions in 2021
Mesoscale Discussion 1471
The Storm Prediction Center issued this mesoscale discussion at Aug 11, 2021, 4:49 AM CDT for Adams County, Illinois; 30 counties in Missouri. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Aug 11, 2021, 4:49 AM CDT (09:49 UTC)
- Expired
- Aug 11, 2021, 6:15 AM CDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 31 counties
Adams County, IL, Adair County, MO, Audrain County, MO, Boone County, MO, Caldwell County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Clay County, MO, Clinton County, MO, Cooper County, MO, Grundy County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Knox County, MO, Lafayette County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Pettis County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Shelby County, MO, Sullivan County, MO
The radar
The Pleasant Hill radar (KEAX), 131 km from the middle of the area, began a volume at 09:48 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, 9.8 hours before the alert went out and 229 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
- 2591 J/kg
- Mixed-layer CIN
- -154 J/kg
- Mixed-layer LCL
- 1584 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 134 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 8.9
The text
As transmitted.
169
ACUS11 KWNS 110949
SWOMCD
SPC MCD 110949
ILZ000-MOZ000-KSZ000-111115-
Mesoscale Discussion 1471
NWS Storm Prediction Center Norman OK
0449 AM CDT Wed Aug 11 2021
Areas affected...Northern/Central MO
Concerning...Severe potential...Watch unlikely
Valid 110949Z - 111115Z
Probability of Watch Issuance...5 percent
SUMMARY...A few strong storms are possible but the overall risk for
any severe thunderstorms appears low.
DISCUSSION...Elevated thunderstorms have begun to develop within the
warm sector ahead of a low-amplitude shortwave trough moving across
eastern NE. Recent water vapor imagery shows the ascent attendant
to this system well (in the form of cooling cloud tops across
northern/central). Steep mid-level lapse rates are in place,
contributing to moderate buoyancy. In contrast, vertical shear is
relatively modest, particularly in the layer where the buoyancy
resides (roughly above 700 mb). As such, updraft longevity will
likely be tempered, which should also limit any hail potential.
..Mosier/Guyer.. 08/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILX...LSX...DVN...EAX...
LAT...LON 39529464 40149361 40499191 40139084 39049105 38679320
38799466 39529464SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 7:38 PM CDT | Severe Thunderstorm Watch | SPC | Kankakee | 5 hr |
| Aug 11, 1:20 AM CDT | Mesoscale Discussion | SPC | Bureau, Ford, Fulton, Grundy, Henry, Iroquois and 15 more | 115 min |
| Aug 11, 6:26 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Fulton, Hancock, Henderson and 12 more | 2 hr |
| Aug 11, 8:34 AM CDT | Mesoscale Discussion | SPC | Bureau, Cook, DeKalb, DuPage, Ford, Grundy and 13 more | 86 min |
| Aug 11, 8:52 AM CDT | Severe Thunderstorm Watch | SPC | Cook, DeKalb, DuPage, Grundy, Kane, Kankakee and 6 more | 4 hr |
| Aug 11, 9:52 AM CDT | Mesoscale Discussion | SPC | Cook, DuPage, Grundy, Kane, Kankakee, Lake and 1 more | 83 min |
| Aug 11, 3:56 PM CDT | Mesoscale Discussion | SPC | Carroll, Hancock, Henderson, Henry, Jo Daviess, Mercer and 2 more | 3 hr |
| Aug 11, 5:40 PM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess, Stephenson | 95 min |
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.