Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1246
The Storm Prediction Center issued this mesoscale discussion at Jul 10, 2021, 5:33 PM CDT for 16 counties in Illinois; Gibson County, Posey County, Vanderburgh County, Indiana; Henderson County, Union County, Kentucky. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- Jul 10, 2021, 5:33 PM CDT (22:33 UTC)
- Expired
- Jul 10, 2021, 7:00 PM CDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 365
All 21 counties
Clay County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Perry County, IL, Pope County, IL, Richland County, IL, Saline County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Posey County, IN, Vanderburgh County, IN, Henderson County, KY, Union County, KY
The radar
The Evansville,IN radar (KVWX), 84 km from the middle of the area, began a volume at 22:33 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
Lincoln, IL (KILX), launched 12:00Z, 10.6 hours before the alert went out and 230 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
- 952 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 68 m²/s²
- 0-3 km storm-relative helicity
- 156 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
561
ACUS11 KWNS 102233
SWOMCD
SPC MCD 102233
INZ000-KYZ000-ILZ000-110000-
Mesoscale Discussion 1246
NWS Storm Prediction Center Norman OK
0533 PM CDT Sat Jul 10 2021
Areas affected...Southern IL ...Far Southwest IN....Far Eastern KY
Concerning...Severe Thunderstorm Watch 365...
Valid 102233Z - 110000Z
The severe weather threat for Severe Thunderstorm Watch 365
continues.
SUMMARY...Threat for damaging wind gust will continue across
southern IL as the convective line surges eastward. The need for a
downstream watch is currently unlikely, but convective trends will
be monitored closely.
DISCUSSION...Recent radar imagery has shown a trend towards faster
eastward progression of the convective cluster currently ongoing
across southern IL. This quicker eastward progression suggests the
cluster has transitioned to a more cold pool driven convective line.
Recent storm motion is estimated to be around 33 kt within the most
progressive portion of the line moving into Jefferson and Franklin
Counties.
Echo tops and MESH cores suggest these updrafts are not overly
strong, limiting the hail potential. Even so, strong downdrafts and
the surging cold pool will continue to produce damaging wind gusts.
At its current speed, the line is expected reach the edge of Severe
Thunderstorm Watch 365 by 00Z. The need for a downstream watch is
unlikely, given current storm trends and air mass stabilization from
ongoing storms over the region. Nevertheless, trends will be
monitored closely.
..Mosier/Thompson.. 07/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...PAH...ILX...LSX...
LAT...LON 38378925 38868857 38618743 37888725 37398791 37428875
37848969 38018980 38378925SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 9, 7:08 PM CDT | Severe Thunderstorm Watch | SPC | Hancock, Henderson, McDonough, Warren | 3 hr |
| Jul 9, 7:54 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 9 more | 36 min |
| Jul 9, 8:18 PM CDT | Tornado Watch | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 9 more | 6 hr |
| Jul 9, 10:26 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 7 more | 64 min |
| Jul 10, 1:01 AM CDT | Mesoscale Discussion | SPC | Clinton, Jackson, Monroe, Perry, Randolph, Saint Clair and 3 more | 59 min |
| Jul 10, 1:36 AM CDT | Severe Thunderstorm Watch | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Jackson and 10 more | 4 hr |
| Jul 10, 3:09 AM CDT | Mesoscale Discussion | SPC | Alexander, Franklin, Jackson, Johnson, Pulaski, Saline and 2 more | 2 hr |
| Jul 10, 1:25 PM CDT | Mesoscale Discussion | SPC | Alexander, Clay, Clinton, Edwards, Franklin, Gallatin and 22 more | 2 hr |
| Jul 10, 2:01 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Bond, Clay, Clinton, Crawford, Edwards and 28 more | 8 hr |
| Jul 10, 3:09 PM CDT | Mesoscale Discussion | SPC | Cass, Champaign, DeWitt, Douglas, Ford, Logan and 8 more | 96 min |
| Jul 10, 3:05 PM CDT | Mesoscale Discussion | SPC | Adair, Barren, Bell, Boyle, Breathitt, Butler and 42 more | 115 min |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Kentucky, 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.