Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 1991
The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 7:34 PM CST for 22 counties in Arkansas. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Dec 10, 2021, 7:34 PM CST (01:34 UTC)
- Expired
- Dec 10, 2021, 9:00 PM CST
- In force
- 86 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 552...555
All 22 counties
Clark County, AR, Crittenden County, AR, Cross County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Little River County, AR, Lonoke County, AR, Monroe County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR
The radar
The Little Rock radar (KLZK), 29 km from the middle of the area, began a volume at 01:34 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 00:00Z, 1.6 hours before the alert went out and 182 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
- 1725 J/kg
- Mixed-layer CIN
- -13 J/kg
- Mixed-layer LCL
- 759 m above ground
- 0-6 km bulk shear
- 78 kt
- 0-1 km storm-relative helicity
- 398 m²/s²
- 0-3 km storm-relative helicity
- 420 m²/s²
- Significant tornado parameter
- 4.8
- Supercell composite
- 16.2
The text
As transmitted.
320
ACUS11 KWNS 110135
SWOMCD
SPC MCD 110134
TNZ000-ARZ000-MSZ000-OKZ000-110300-
Mesoscale Discussion 1991
NWS Storm Prediction Center Norman OK
0734 PM CST Fri Dec 10 2021
Areas affected...portions of southwest into central and eastern
Arkansas
Concerning...Tornado Watch 552...555...
Valid 110134Z - 110300Z
The severe weather threat for Tornado Watch 552, 555 continues.
SUMMARY...An uptick in the severe threat, including strong
tornadoes, appears evident across southwest into east-central
Arkansas. The locally higher tornado threat may persist with the
more dominant supercells for at least a few hours.
DISCUSSION...Multiple storms, including sustained supercells, have
recently organized across portions of central and eastern Arkansas,
with a discrete supercell also entering far southwest Arkansas. MRMS
mosaic radar shows intense low-level rotation tracks associated with
the more dominant supercells just north of LZK, and these storms are
expected to progress across a moist, unstable/minimally capped
environment. The latest VWPs from SHV to NQA depict long, curved
hodographs given the presence of a broad, intense LLJ overspreading
the area. These VWPs and 01Z mesoanalysis depict 0-1 km and
effective SRH in the 250-400 m2/s2 range, supporting the risk for
sustained, strong tornadoes across southwest into eastern AR for at
least the next few hours.
..Squitieri/Grams.. 12/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...LZK...SHV...
LAT...LON 33749450 35059249 35699171 35869092 35799038 35659020
35259013 34829031 34489129 34009274 33589421 33749450SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 6:22 PM CST | Mesoscale Discussion | SPC | Craighead, Greene, Jackson, Mississippi, Poinsett | 53 min |
| Dec 10, 6:34 PM CST | Tornado Watch | SPC | Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 2 more | 4 hr |
| Dec 10, 6:37 PM CST | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more | 83 min |
| Dec 10, 6:51 PM CST | Tornado Watch | SPC | Baxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more | 4 hr |
| Dec 10, 7:54 PM CST | Mesoscale Discussion | SPC | Boone, Carroll, Crawford, Franklin, Johnson, Logan and 7 more | 2 hr |
| Dec 10, 9:40 PM CST | Mesoscale Discussion | SPC | Arkansas, Clark, Cleveland, Craighead, Crittenden, Cross and 13 more | 2 hr |
| Dec 10, 10:00 PM CST | Mesoscale Discussion | SPC | Ashley, Bradley, Calhoun, Chicot, Columbia, Desha and 5 more | 90 min |
| Dec 10, 10:09 PM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 17 more | 96 min |
| Dec 10, 10:44 PM CST | Tornado Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 16 more | 6 hr |
| Dec 11, 2:00 AM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Desha and 4 more | 90 min |
Nearby
Mesoscale Discussions in Arkansas, 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.