Alert archive / Indiana / Mesoscale Discussions in 2021
Mesoscale Discussion 1598
The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2021, 8:14 PM CDT for 8 counties in Illinois; 10 counties in Indiana; 5 counties in Michigan. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 24, 2021, 8:14 PM CDT (01:14 UTC)
- Expired
- Aug 24, 2021, 10:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 23 counties
Grundy County, IL, Kankakee County, IL, Knox County, IL, Livingston County, IL, Marshall County, IL, Peoria County, IL, Will County, IL, Woodford County, IL, Elkhart County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Saint Joseph County, IN, Starke County, IN, Branch County, MI, Calhoun County, MI, Cass County, MI, Kalamazoo County, MI, Saint Joseph County, MI
The radar
The Chicago radar (KLOT), 44 km from the middle of the area, began a volume at 01:14 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, 1.2 hours before the alert went out and 165 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
- 2737 J/kg
- Mixed-layer CIN
- -9 J/kg
- Mixed-layer LCL
- 1274 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 43 m²/s²
- 0-3 km storm-relative helicity
- 120 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.3
The text
As transmitted.
445
ACUS11 KWNS 250114
SWOMCD
SPC MCD 250114
MIZ000-INZ000-ILZ000-250315-
Mesoscale Discussion 1598
NWS Storm Prediction Center Norman OK
0814 PM CDT Tue Aug 24 2021
Areas affected...Northern IL...Northern IN...Southwest Lower MI
Concerning...Severe potential...Watch unlikely
Valid 250114Z - 250315Z
Probability of Watch Issuance...20 percent
SUMMARY...A few strong/severe wind gusts are possible the next few
hours as convection propagates southeast. Severe thunderstorm watch
is not currently warranted.
DISCUSSION...Multi-faceted complex of storms that originated over
the upper MS Valley earlier today has progressed southeast and
currently extends along a corridor from southwest lower MI-northwest
IN-northern IL. Severe wind gusts were more common with this
activity across portions of IA/northern IL late this afternoon, but
have recently waned in intensity with many storms now producing
gusts on the order of 35kt. This elongated corridor of convection is
propagating southeast at roughly 20-25kt and should continue for the
next few hours as sufficient cold pool trails the leading storms.
Given the generally sub-severe wind reports, at this time a new
severe thunderstorm watch is not warranted.
..Darrow/Bunting.. 08/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...GRR...LOT...ILX...DVN...
LAT...LON 40919043 41388837 41768675 42378558 42168455 41418522
40528954 40919043SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 25, 4:02 PM CDT | Mesoscale Discussion | SPC | Bureau, Champaign, Clark, Coles, DeWitt, Douglas and 28 more | 88 min |
| Aug 25, 11:46 AM CDT | Mesoscale Discussion | SPC | Bartholomew, Boone, Brown, Clay, Dearborn, Decatur and 27 more | 2 hr |
Nearby
Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Michigan, 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.