Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 1983
The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 5:17 PM CST for 15 counties in Mississippi; 7 counties in Tennessee. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Dec 10, 2021, 5:17 PM CST (23:17 UTC)
- Expired
- Dec 10, 2021, 6:45 PM CST
- In force
- 88 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 22 counties
Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Yalobusha County, MS, Chester County, TN, Fayette County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Madison County, TN, McNairy County, TN
The radar
The Memphis radar (KNQA), 106 km from the middle of the area, began a volume at 23:19 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
Little Rock, AR (KLZK), launched 12:00Z, 11.3 hours before the alert went out and 89 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
- 547 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 475 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 199 m²/s²
- 0-3 km storm-relative helicity
- 200 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 2.9
The text
As transmitted.
498
ACUS11 KWNS 102318
SWOMCD
SPC MCD 102317
ALZ000-TNZ000-MSZ000-110045-
Mesoscale Discussion 1983
NWS Storm Prediction Center Norman OK
0517 PM CST Fri Dec 10 2021
Areas affected...Northern Mississippi and portions of southwest
Tennessee.
Concerning...Severe potential...Watch possible
Valid 102317Z - 110045Z
Probability of Watch Issuance...60 percent
SUMMARY...Watch 52 may need to be expanded eastward into northern
Mississippi and western Tennessee
DISCUSSION...Showers continue to deepen in the warm air advection
regime along and east of the Mississippi River. As they deepen, some
low-level rotation has been evident on some of the better
mini-supercell structures. Expect this threat to continue as storms
deepen further in a region of 0 to 1 km SRH around 250 m2/s2 per
KNQA VWP. Eventual severe intensity is expected out of this
activity, but timing is the primary question. If these storms
intensify in the next hour, watch 552 may need to be expanded across
the remainder of the MEG CWA. However, if the storm intensity
remains muted for the next 60 to 90 minutes, this area may be
covered by an eventual watch which will likely be needed east of
tornado watch 552.
..Bentley/Grams.. 12/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HUN...MEG...JAN...
LAT...LON 35448926 35798849 35268800 34238820 33788858 33838977
34109032 35448926SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 3:07 PM CST | Tornado Watch | SPC | Coahoma, DeSoto, Marshall, Panola, Quitman, Tate and 1 more | 11 hr |
| Dec 10, 4:45 PM CST | Mesoscale Discussion | SPC | Coahoma, DeSoto, Marshall, Panola, Quitman, Tate and 1 more | 90 min |
| Dec 10, 1:35 PM CST | Mesoscale Discussion | SPC | Lake | 2 hr |
| Dec 10, 5:52 PM CST | Mesoscale Discussion | SPC | Benton, Cheatham, Davidson, Dickson, Hickman, Houston and 9 more | 83 min |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale 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.