Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 1965
The Storm Prediction Center issued this mesoscale discussion at Dec 6, 2021, 3:01 AM CST for 19 counties in Arkansas; Dunklin County, Pemiscot County, Missouri; 18 counties in Tennessee. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- Dec 6, 2021, 3:01 AM CST (09:01 UTC)
- Expired
- Dec 6, 2021, 4:00 AM CST
- In force
- 59 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 550
All 39 counties
Craighead County, AR, Crittenden County, AR, Cross County, AR, Faulkner County, AR, Garland County, AR, Jackson County, AR, Lee County, AR, Lonoke County, AR, Mississippi County, AR, Monroe County, AR, Montgomery County, AR, Perry County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Dunklin County, MO, Pemiscot County, MO, Benton County, TN, Carroll County, TN, Crockett County, TN, Dyer County, TN, Gibson County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Houston County, TN, Humphreys County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Stewart County, TN, Tipton County, TN, Weakley County, TN
The radar
The Memphis radar (KNQA), 93 km from the middle of the area, began a volume at 09:03 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
Little Rock, AR (KLZK), launched 00:00Z, 9.0 hours before the alert went out and 105 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
- 1313 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 793 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 252 m²/s²
- 0-3 km storm-relative helicity
- 326 m²/s²
- Significant tornado parameter
- 2.2
- Supercell composite
- 19.4
The text
As transmitted.
911
ACUS11 KWNS 060901
SWOMCD
SPC MCD 060901
TNZ000-KYZ000-MOZ000-ARZ000-MSZ000-061000-
Mesoscale Discussion 1965
NWS Storm Prediction Center Norman OK
0301 AM CST Mon Dec 06 2021
Areas affected...central and northeastern Arkansas into western
Tennessee
Concerning...Severe Thunderstorm Watch 550...
Valid 060901Z - 061000Z
The severe weather threat for Severe Thunderstorm Watch 550
continues.
SUMMARY...Local risk for gusty/damaging winds will continue over the
next 1 to 2 hours. However, a new WW -- to extend beyond the
scheduled 10Z expiration of WW 550 -- appears unnecessary given
expected/limited risk.
DISCUSSION...Latest radar loop shows a band of storms -- exhibiting
anafrontal characteristics -- moving across central and northeastern
Arkansas at this time, representing the tail end of the longer,
frontal band of storms that extends east-northeastward to
southwestern Ohio. Meanwhile, a second, more loosely organized
pre-frontal convective band continues to evolve near and east of the
Mississippi River into western Tennessee.
Ahead of the convection, a boundary layer featuring dewpoints in the
upper 50s to low 60s is contributing to modest mixed-layer CAPE
(around 500 J/kg per the latest RUC objective analyses). However, a
slightly stable boundary layer is also hinted at, owing to the
diurnal cooling. This, combined with front-parallel flow aloft,
continues to limit overall risk for damaging winds.
While some uptick in convective intensity may occur as storms
approach/cross the Tennessee Valley, where the axis of instability
resides, substantial increase in what has proven to be minimal
severe potential is not expected. Therefore, while we will continue
to monitor convective and environmental evolution, new WW issuance
is not currently anticipated.
..Goss.. 12/06/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OHX...PAH...MEG...LZK...
LAT...LON 34509376 35319235 36408950 36608732 35818797 34419163
34509376SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 5, 8:06 PM CST | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Clay, Crawford and 17 more | 114 min |
| Dec 5, 8:54 PM CST | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Carroll, Clay, Cleburne and 39 more | 7 hr |
| Dec 5, 11:17 PM CST | Mesoscale Discussion | SPC | Baxter, Boone, Crawford, Franklin, Fulton, Izard and 9 more | 118 min |
| Dec 6, 5:06 AM CST | Mesoscale Discussion | SPC | Arkansas, Jefferson, Lee, Monroe, Phillips | 114 min |
| Dec 5, 8:59 PM CST | Tornado Watch | SPC | Bollinger, Butler, Cape Girardeau, Carter, Iron, Madison and 7 more | 7 hr |
| Dec 5, 11:28 PM CST | Mesoscale Discussion | SPC | Bollinger, Butler, Cape Girardeau, Madison, Mississippi, New Madrid and 4 more | 2 hr |
| Dec 6, 2:47 AM CST | Mesoscale Discussion | SPC | Mississippi | 88 min |
Nearby
Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in Missouri, 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.