Alert archive / Tennessee / Mesoscale Discussions in 2021
Mesoscale Discussion 842
The Storm Prediction Center issued this mesoscale discussion at Jun 2, 2021, 9:05 PM CDT for 12 counties in Tennessee. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Jun 2, 2021, 9:05 PM CDT (02:05 UTC)
- Expired
- Jun 2, 2021, 10:30 PM CDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Benton County, TN, Cheatham County, TN, Davidson County, TN, Dickson County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Montgomery County, TN, Perry County, TN, Rutherford County, TN, Williamson County, TN, Wilson County, TN
The radar
The Nashville radar (KOHX), 59 km from the middle of the area, began a volume at 02:05 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
Nashville Metro, TN (KBNA), launched 00:00Z, 2.1 hours before the alert went out and 53 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
- 389 J/kg
- Mixed-layer CIN
- -48 J/kg
- Mixed-layer LCL
- 931 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 190 m²/s²
- 0-3 km storm-relative helicity
- 228 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 5.1
The text
As transmitted.
112
ACUS11 KWNS 030206
SWOMCD
SPC MCD 030205
TNZ000-030330-
Mesoscale Discussion 0842
NWS Storm Prediction Center Norman OK
0905 PM CDT Wed Jun 02 2021
Areas affected...portions of Middle Tennessee
Concerning...Severe potential...Watch unlikely
Valid 030205Z - 030330Z
Probability of Watch Issuance...20 percent
SUMMARY...A couple damaging gusts, large hail, and perhaps a tornado
remain possible over the next couple of hours. The brief, isolated
nature of the severe threat precludes a WW issuance.
DISCUSSION...A few discrete storm structures have recently exhibited
transient supercell characteristics over the past hour, with brief
instances of low to mid-level rotation noted via KOHX and MRMS
mosaic radar data. MRMS MESH also suggests that up 1 inch diameter
stones may be falling with some of the stronger storms. The 00Z BNA
observed sounding sampled near 1500 J/kg SBCAPE, with over 500 J/kg
MLCAPE. While this instability is gradually waning with nocturnal
cooling, the BNA sounding and 01Z KOHX VWP have sampled around 150
m2/s2 0-1 km SRH, all of which is included in the effective storm
inflow layer. As such, a tornado cannot be ruled out with any of the
stronger storms that manages to develop a persistent low-level
mesocyclone, in addition to a damaging gust or two and perhaps some
marginally severe hail. However, given gradual boundary-layer
stabilization, the ongoing storms are likely at peak intensity, with
the spatial coverage of severe expected to be quite sparse. As such,
a WW issuance is not currently planned.
..Squitieri/Thompson.. 06/03/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OHX...MEG...
LAT...LON 35788833 36278797 36558771 36568725 36438651 36298615
36068604 35828617 35658676 35648787 35788833SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 3, 12:26 PM CDT | Mesoscale Discussion | SPC | Bedford, Bledsoe, Cannon, Cheatham, Clay, Coffee and 29 more | 2 hr |
Nearby
Mesoscale Discussions in Tennessee, 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.