Alert archive / Indiana / Mesoscale Discussions in 2021
Mesoscale Discussion 1001
The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2021, 8:53 PM EDT for 4 states. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- Jun 18, 2021, 8:53 PM EDT (00:53 UTC)
- Expired
- Jun 18, 2021, 10:00 PM EDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 279...280
All 70 counties
Bartholomew County, IN, Brown County, IN, Clark County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Floyd County, IN, Franklin County, IN, Greene County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Ohio County, IN, Orange County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Sullivan County, IN, Switzerland County, IN, Union County, IN, Washington County, IN, Boone County, KY, Boyd County, KY, Bracken County, KY, Campbell County, KY, Carroll County, KY, Carter County, KY, Fleming County, KY, Franklin County, KY, Gallatin County, KY, Grant County, KY, Greenup County, KY, Harrison County, KY, Henry County, KY, Kenton County, KY, Lewis County, KY, Mason County, KY, Nicholas County, KY, Oldham County, KY, Owen County, KY, Pendleton County, KY, Robertson County, KY, Scott County, KY, Shelby County, KY, Trimble County, KY, Adams County, OH, Brown County, OH, Butler County, OH, Clermont County, OH, Clinton County, OH, Fayette County, OH, Gallia County, OH, Greene County, OH, Hamilton County, OH, Highland County, OH, Jackson County, OH, Lawrence County, OH, Montgomery County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Scioto County, OH, Warren County, OH, Cabell County, WV
The radar
The Cincinnati radar (KILN), 110 km from the middle of the area, began a volume at 00:54 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Cncnati-Daytn, OH (KILN), launched 00:00Z, 0.9 hours before the alert went out and 113 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
- 2257 J/kg
- Mixed-layer CIN
- -56 J/kg
- Mixed-layer LCL
- 1236 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 214 m²/s²
- 0-3 km storm-relative helicity
- 240 m²/s²
- Significant tornado parameter
- 1.9
- Supercell composite
- 17.6
The text
As transmitted.
032
ACUS11 KWNS 190053
SWOMCD
SPC MCD 190053
WVZ000-OHZ000-KYZ000-INZ000-ILZ000-190200-
Mesoscale Discussion 1001
NWS Storm Prediction Center Norman OK
0753 PM CDT Fri Jun 18 2021
Areas affected...southern portions of IN/OH...northern KY
Concerning...Tornado Watch 279...280...
Valid 190053Z - 190200Z
The severe weather threat for Tornado Watch 279, 280 continues.
SUMMARY...The severe weather threat continues with Tornado Watch 279
and Severe Thunderstorm Watch 280. A downstream watch may be needed
south/southeast of existing watches prior to 02z.
DISCUSSION...Several supercell thunderstorms continue within WW
279/280 at 0030z, with strengthening storms also noted near the
IL/IN border near Sullivan, IN. Very large hail, isolated damaging
winds, and at least one tornado have been reported with these
intense storms. Gradual upscale growth is anticipated over the next
few hours as warm advection strengthens and promotes increasing
storm coverage. Linear bowing segments are likely to evolve with
time and continue moving east/southeast across locally extended
portions of WW 279/280 and potentially requiring issuance of one or
more downstream watches prior to 02z. Increasing MLCIN with
southward extent casts some uncertainty on the extent of the severe
risk, however damaging winds, possibly significant, will become an
increasingly prominent risk over the next few hours. Severe hail
will remain possible with persistent supercell structures. Some
tornado risk will also continue with both supercell and bowing
segments given background environment low-level SRH of 200-250
m2/s2.
Observational trends will continue to be monitored for the potential
for additional watch issuance.
..Bunting/Guyer.. 06/19/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RLX...JKL...ILN...LMK...IND...PAH...ILX...
LAT...LON 39298662 39748545 39918464 39848405 39608347 39328292
39058237 38528203 38168236 38248405 38238478 38218574
38388648 38528728 38718756 39128771 39298662SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 18, 9:09 PM EDT | Severe Thunderstorm Watch | SPC | Clark, Dearborn, Franklin, Jefferson, Ohio, Ripley and 3 more | 6 hr |
| Jun 19, 1:02 AM EDT | Mesoscale Discussion | SPC | Bartholomew, Boone, Brown, Clay, Clinton, Daviess and 25 more | 88 min |
| Jun 19, 3:10 AM EDT | Mesoscale Discussion | SPC | Bartholomew, Brown, Clay, Fountain, Greene, Hendricks and 15 more | 2 hr |
| Jun 18, 11:09 PM EDT | Mesoscale Discussion | SPC | Bath, Boyd, Carter, Elliott, Fleming, Lawrence and 3 more | 96 min |
| Jun 19, 7:07 PM EDT | Mesoscale Discussion | SPC | Carroll, Columbiana, Geauga, Jefferson, Mahoning, Portage and 3 more | 83 min |
Nearby
Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Kentucky, 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.