Alert archive / Illinois / Mesoscale Discussions in 2017
Mesoscale Discussion 481
The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2017, 8:58 PM CDT for 15 counties in Illinois; 15 counties in Indiana; 11 counties in Michigan. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Apr 10, 2017, 8:58 PM CDT (01:58 UTC)
- Expired
- Apr 10, 2017, 10:00 PM CDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
All 41 counties
Champaign County, IL, Clark County, IL, Coles County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Ford County, IL, Iroquois County, IL, Jasper County, IL, Kankakee County, IL, Moultrie County, IL, Piatt County, IL, Shelby County, IL, Vermilion County, IL, Benton County, IN, Fountain County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Newton County, IN, Parke County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Tippecanoe County, IN, Vermillion County, IN, Warren County, IN, White County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Cass County, MI, Clinton County, MI, Eaton County, MI, Ionia County, MI, Kalamazoo County, MI, Kent County, MI, Shiawassee County, MI, Van Buren County, MI
The radar
The Northern Indiana radar (KIWX), 93 km from the middle of the area, began a volume at 01:57 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 00:00Z, 2.0 hours before the alert went out and 187 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
- 846 J/kg
- Mixed-layer CIN
- -16 J/kg
- Mixed-layer LCL
- 1335 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 37 m²/s²
- 0-3 km storm-relative helicity
- 111 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.3
The text
As transmitted.
596
ACUS11 KWNS 110159
SWOMCD
SPC MCD 110158
MIZ000-INZ000-ILZ000-110300-
Mesoscale Discussion 0481
NWS Storm Prediction Center Norman OK
0858 PM CDT Mon Apr 10 2017
Areas affected...southwestern Michigan...western Indiana...and
eastern Illinois
Concerning...Severe Thunderstorm Watch 138...
Valid 110158Z - 110300Z
The severe weather threat for Severe Thunderstorm Watch 138
continues.
SUMMARY...A lingering threat for isolated hail/wind will persist
across the discussion area through at least 03Z.
DISCUSSION...Scattered thunderstorms continue to persist across the
discussion area at this time. Some of the storms have recently
exhibited weak rotation over the past 1-2 hours - especially in
eastern Illinois and northwestern Indiana. Hail (locally exceeding
1 inch in diameter) remains the biggest threat with this activity
given weak to moderate instability and cold (-16 to -18C at 500mb)
temperatures aloft. An isolated wind gust also cannot be completely
ruled out with stronger storms. The ongoing WW (138) expires at
03Z. It appears possible that an isolated hail/wind threat may
exist beyond this expiration time, which may require local temporal
extensions of the watch.
..Cook/Guyer.. 04/11/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DTX...IWX...GRR...IND...LOT...ILX...LSX...
LAT...LON 39418920 40138872 41078796 42658623 43128546 43288479
43288421 43148398 42748417 42338482 41988571 41428631
40488679 39888710 39318754 38938818 38968880 39098921
39418920Nearby
Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Indiana, 2017Mesoscale Discussions in Michigan, 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.