Alert archive / Missouri / Mesoscale Discussions in 2021
Mesoscale Discussion 1013
The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2021, 2:12 PM CDT for 13 counties in Illinois; 19 counties in Missouri. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Jun 19, 2021, 2:12 PM CDT (19:12 UTC)
- Expired
- Jun 19, 2021, 3:45 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 32 counties
Bond County, IL, Calhoun County, IL, Clinton County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Monroe County, IL, Montgomery County, IL, Pike County, IL, Saint Clair County, IL, Scott County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO, Washington County, MO
The radar
The St Louis radar (KLSX), 27 km from the middle of the area, began a volume at 19:15 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 7.2 hours before the alert went out and 240 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1960 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 142 m²/s²
- 0-3 km storm-relative helicity
- 203 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
763
ACUS11 KWNS 191912
SWOMCD
SPC MCD 191912
ILZ000-MOZ000-192045-
Mesoscale Discussion 1013
NWS Storm Prediction Center Norman OK
0212 PM CDT Sat Jun 19 2021
Areas affected...east-central Missouri and west-central Illinois
Concerning...Severe potential...Watch possible
Valid 191912Z - 192045Z
Probability of Watch Issuance...60 percent
SUMMARY...A few supercells are possible in the next 1 to 2 hours and
may grow upscale into a cluster. The primary threat will likely be
large hail with some threat for damaging winds.
DISCUSSION...An area of agitated cumulus has developed on the
eastern periphery of an EML plume extending from the Plains into
central Missouri. Within this cu field one storm has recently formed
near the Mississippi river north of Saint Louis. In this region,
dewpoints are in the low to mid 70s with temperatures in the mid 80s
to near 90. This warming/moistening has proven sufficient to reduce
inhibition across this region with little CINH remaining according
to SPC mesoanalysis. In addition, SPC mesoanalysis shows MLCAPE
around 2500 to 3000 J/kg.
Regional VWPs and SPC mesoanalysis shows around 40 to 45 knots of
northwesterly shear across the region. This should be sufficient for
storms to organize into supercells. While 12Z CAM guidance has
struggled with the timing and evolution of this activity, there is
consensus for upscale growth into a cluster once storms develop from
each of the CAMS. However, the downstream airmass becomes less
favorable with less instability and increasing
inhibition/subsidence. Therefore, this activity may struggle to
propagate forward and may back build westward toward the greater
instability through the afternoon/evening. While damaging wind may
be possible, large hail will likely be the greatest threat with this
activity.
..Bentley/Hart.. 06/19/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...ILX...LSX...SGF...EAX...
LAT...LON 38168947 37849062 38019172 38539225 39169261 39569264
39699223 39839124 39668987 39318933 38768907 38168947SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 18, 8:53 PM CDT | Mesoscale Discussion | SPC | Bond, Brown, Cass, Christian, Clark, Clay and 26 more | 97 min |
| Jun 18, 9:20 PM CDT | Severe Thunderstorm Watch | SPC | Cass, Champaign, Christian, Clark, Clay, Coles and 33 more | 7 hr |
| Jun 18, 9:27 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Hancock, Henderson, McDonough, Mercer and 2 more | 2 hr |
| Jun 18, 10:08 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Bureau, Hancock, Henderson, Henry and 6 more | 8 hr |
| Jun 19, 2:10 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Champaign, Christian, Clark and 27 more | 2 hr |
| Jun 19, 11:15 AM CDT | Mesoscale Discussion | SPC | Effingham, Fayette, Greene, Macoupin, Montgomery, Morgan and 1 more | 2 hr |
| Jun 19, 2:43 PM CDT | Severe Thunderstorm Watch | SPC | Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 9 more | 7 hr |
| Jun 19, 5:11 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clinton, Greene, Jersey, Macoupin, Madison and 6 more | 64 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.