Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1002
The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2021, 8:53 PM CDT for 32 counties in Illinois. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- Jun 18, 2021, 8:53 PM CDT (01:53 UTC)
- Expired
- Jun 18, 2021, 10:30 PM CDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 32 counties
Bond County, IL, Brown County, IL, Cass County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jasper County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Marion County, IL, Mason County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Richland County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL
The radar
The Lincoln radar (KILX), 67 km from the middle of the area, began a volume at 01:54 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 00:00Z, 1.9 hours before the alert went out and 92 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
- 2124 J/kg
- Mixed-layer CIN
- -145 J/kg
- Mixed-layer LCL
- 1616 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 165 m²/s²
- 0-3 km storm-relative helicity
- 200 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 4.0
The text
As transmitted.
801
ACUS11 KWNS 190154
SWOMCD
SPC MCD 190153
INZ000-ILZ000-190330-
Mesoscale Discussion 1002
NWS Storm Prediction Center Norman OK
0853 PM CDT Fri Jun 18 2021
Areas affected...portions of central/southern IL
Concerning...Severe potential...Watch likely
Valid 190153Z - 190330Z
Probability of Watch Issuance...80 percent
SUMMARY...A small cluster of severe thunderstorms will move
east/southeast this evening with large hail and damaging winds the
main threats. Additional thunderstorm development is anticipated,
and a watch will likely be needed prior to 03z.
DISCUSSION...A small cluster of thunderstorms has developed near
Springfield, IL as of 0150z, in the vicinity of an east-west front.
Strong surface-based instability remains in place along with 30-35
kts of effective shear, favoring supercells initially with a risk
for large hail, potentially significant, in addition to damaging
downburst winds. Strengthening warm advection this evening will
contribute to additional thunderstorm development, with storms
evolving into bowing segments with time and continuing to pose a
severe risk into the early overnight hours.
Observational trends are being monitored and a watch is likely prior
to 03z.
..Bunting/Guyer.. 06/19/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...PAH...ILX...LSX...DVN...
LAT...LON 38518794 38678951 39029036 39739113 40249124 40439103
40469035 40258921 39998816 39868766 38958757 38518794SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| 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, 2:12 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clinton, Greene, Jersey, Macoupin and 7 more | 93 min |
| 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 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.