Alert archive / Illinois / Mesoscale Discussions in 2017
Mesoscale Discussion 1012
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2017, 2:25 PM CDT for 8 counties in Illinois; 5 counties in Indiana. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2017, 2:25 PM CDT (19:25 UTC)
- Expired
- Jun 13, 2017, 5:00 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
Counties DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Will County, IL, Jasper County, IN, Lake County, IN, Newton County, IN, Pulaski County, IN, Starke County, IN
The radar
The Chicago radar (KLOT), 26 km from the middle of the area, began a volume at 19:25 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, 7.4 hours before the alert went out and 155 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
- 1770 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 867 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- -49 m²/s²
- 0-3 km storm-relative helicity
- -40 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
441
ACUS11 KWNS 131925
SWOMCD
SPC MCD 131925
INZ000-ILZ000-132200-
Mesoscale Discussion 1012
NWS Storm Prediction Center Norman OK
0225 PM CDT Tue Jun 13 2017
Areas affected...Portions of northern IL and northwest IN
Concerning...Severe potential...Watch unlikely
Valid 131925Z - 132200Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated severe-thunderstorm potential will exist into the
early evening hours. Watch issuance will not be needed.
DISCUSSION...Low-level ascent along a composite outflow/lake-breeze
boundary is supporting increasingly agitated cumulus fields and
isolated thunderstorm development from north-central IL into
northwest IN. Strong diurnal heating south of this boundary
continues, with temperatures having warmed into the lower/middle 90s
amid dewpoints in the upper 60s to lower 70s, supporting 1500-2500
J/kg of MLCAPE and little capping. A few robust convective cores
capable of isolated severe hail/wind may occur into early evening.
However, with this activity approximately aligned with a
larger-scale ridge aloft associated with a dearth of deep ascent and
paucity of ambient tropospheric flow/vertical shear, organized
convection and greater coverage of severe storms are not expected.
..Cohen/Hart.. 06/13/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...LOT...
LAT...LON 40888814 41168885 41748916 42178903 42078837 41798797
41528740 41428648 41228629 40898687 40888814SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 11:18 AM CDT | Mesoscale Discussion | SPC | Adams, Allen, Bartholomew, Blackford, Boone, Brown and 51 more | 2 hr |
Nearby
Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Indiana, 2017Every mesoscale discussion in 2017
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.