Alert archive / Indiana / Mesoscale Discussions in 2021
Mesoscale Discussion 2012
The Storm Prediction Center issued this mesoscale discussion at Dec 11, 2021, 2:46 AM EST for 27 counties in Indiana; 8 counties in Ohio. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- Dec 11, 2021, 2:46 AM EST (07:46 UTC)
- Expired
- Dec 11, 2021, 3:45 AM EST
- In force
- 59 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 557...560
All 35 counties
Bartholomew County, IN, Brown County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Delaware County, IN, Fayette County, IN, Franklin County, IN, Greene County, IN, Hancock County, IN, Henry County, IN, Jackson County, IN, Jay County, IN, Jennings County, IN, Johnson County, IN, Lawrence County, IN, Madison County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Morgan County, IN, Randolph County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Union County, IN, Wayne County, IN, Auglaize County, OH, Butler County, OH, Darke County, OH, Mercer County, OH, Miami County, OH, Montgomery County, OH, Preble County, OH, Shelby County, OH
The radar
The Indianapolis radar (KIND), 66 km from the middle of the area, began a volume at 07:49 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
Cncnati-Daytn, OH (KILN), launched 00:00Z, 7.8 hours before the alert went out and 149 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
- 519 m above ground
- 0-6 km bulk shear
- 71 kt
- 0-1 km storm-relative helicity
- 325 m²/s²
- 0-3 km storm-relative helicity
- 431 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
960
ACUS11 KWNS 110747
SWOMCD
SPC MCD 110746
OHZ000-INZ000-110845-
Mesoscale Discussion 2012
NWS Storm Prediction Center Norman OK
0146 AM CST Sat Dec 11 2021
Areas affected...central into northern IN and western OH
Concerning...Tornado Watch 557...560...
Valid 110746Z - 110845Z
The severe weather threat for Tornado Watch 557, 560 continues.
SUMMARY...Sporadic strong wind gusts and/or a tornado remain
possible across parts of central Indiana into western Ohio the next
few hours.
DISCUSSION...Strong storms continue tonight from roughly Auglaize
County in western Ohio to Knox County in west-central Indiana. Much
of this area remains within a weakly unstable (100-500 J/kg MLCAPE)
airmass. However, strong vertical shear remains present, resulting
in semi-organized line segments. Low-level shear also remains
favorable for rotation within cells and/or mesovortices. The maximum
relative threat will likely be confined to parts of central Indiana
over the next few hours where instability is greatest. Surface
dewpoints decrease into the upper 50s with northward extent, and a
large area of moderate rainfall has overspread much of western into
central Ohio, resulting in boundary-layer stabilization. As such,
the severe threat should remain confined within WW 557 (which has
been locally extended a couple of hours) and WW 560, and a
downstream watch into central OH is unlikely.
..Leitman.. 12/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILN...LMK...IWX...IND...
LAT...LON 38738605 38918518 39288450 39728407 40498395 40658402
40728422 40688469 40608492 40368553 40168584 39048705
38758724 38648717 38608696 38658651 38738605SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 7:21 PM EST | Tornado Watch | SPC | Clark, Crawford, Dubois, Floyd, Harrison, Jefferson and 4 more | 10 hr |
| Dec 10, 8:18 PM EST | Mesoscale Discussion | SPC | Bartholomew, Benton, Boone, Brown, Carroll, Cass and 37 more | 87 min |
| Dec 10, 8:47 PM EST | Tornado Watch | SPC | Bartholomew, Benton, Boone, Brown, Clay, Clinton and 24 more | 8 hr |
| Dec 10, 9:35 PM EST | Mesoscale Discussion | SPC | Harrison | 85 min |
| Dec 10, 10:36 PM EST | Mesoscale Discussion | SPC | Vigo | 54 min |
| Dec 10, 11:25 PM EST | Mesoscale Discussion | SPC | Bartholomew, Benton, Blackford, Boone, Brown, Carroll and 50 more | 95 min |
| Dec 11, 12:03 AM EST | Tornado Watch | SPC | Gibson, Pike, Posey, Spencer, Vanderburgh, Warrick | 5 hr |
| Dec 11, 12:08 AM EST | Mesoscale Discussion | SPC | Dearborn, Decatur, Delaware, Fayette, Franklin, Hamilton and 16 more | 67 min |
| Dec 11, 12:20 AM EST | Tornado Watch | SPC | Adams, Allen, Blackford, Carroll, Cass, Dearborn and 27 more | 6 hr |
| Dec 11, 12:28 AM EST | Mesoscale Discussion | SPC | Clay, Daviess, Fountain, Gibson, Greene, Knox and 9 more | 92 min |
Nearby
Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Ohio, 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.