Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 287
The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2021, 6:42 PM CDT for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 27, 2021, 6:42 PM CDT (23:42 UTC)
- Expired
- Mar 27, 2021, 8:45 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 59...60
All 57 counties
Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Drew County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lee County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Mississippi County, AR, Monroe County, AR, Nevada County, AR, Ouachita County, AR, Phillips County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, Union County, AR, White County, AR, Woodruff County, AR, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, Webster Parish, LA, DeSoto County, MS, Tunica County, MS, Crockett County, TN, Fayette County, TN, Haywood County, TN, Lauderdale County, TN, Shelby County, TN, Tipton County, TN, Bowie County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Panola County, TX, Rusk County, TX, Upshur County, TX
The radar
The Little Rock radar (KLZK), 108 km from the middle of the area, began a volume at 23:45 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
Shreveport, LA (KSHV), launched 12:00Z, 11.7 hours before the alert went out and 208 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
- 951 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 670 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 192 m²/s²
- 0-3 km storm-relative helicity
- 238 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 5.6
The text
As transmitted.
964
ACUS11 KWNS 272342
SWOMCD
SPC MCD 272342
TNZ000-MSZ000-ARZ000-LAZ000-TXZ000-OKZ000-280145-
Mesoscale Discussion 0287
NWS Storm Prediction Center Norman OK
0642 PM CDT Sat Mar 27 2021
Areas affected...east Texas...Arkansas...northern Louisiana and
Mississippi...western Tennessee
Concerning...Tornado Watch 59...60...
Valid 272342Z - 280145Z
The severe weather threat for Tornado Watch 59, 60 continues.
SUMMARY...A threat of a few tornadoes, large hail and damaging winds
continues from east Texas into western Tennessee, and will likely
persist this evening.
DISCUSSION...A broken line of storms currently extends from
northeast TX into south-central AR and western TN, well ahead of the
cold front which extends from western AR into north TX as of 01Z.
Several supercells were noted, with a tornado or two ongoing over
northeast TX and northeast AR. Intense hail cores were also observed
across AR.
Given long hodographs and a few hours before the cold front
interacts with these storms, supercell may remain the primary mode
for for a couple hours. Two areas of stronger effective SRH exist,
from northeast TX into northwest LA, and over TN, with values in
excess of 200 m2/s2.
Later this evening, and as the cold front interacts with these
storms, a transition to linear mode is expected, with both damaging
winds and embedded circulations possible.
..Jewell.. 03/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...JAN...LZK...SHV...
LAT...LON 31899407 31639495 31819519 32249516 33309482 34189391
35689094 35968984 35878916 35758895 35388901 34778985
33749147 31899407SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 27, 11:55 AM CDT | Mesoscale Discussion | SPC | Crittenden, Cross, Lee, Mississippi, Poinsett, St. Francis | 3 hr |
| Mar 27, 1:51 PM CDT | Tornado Watch | SPC | Crittenden, Cross, Lee, Mississippi, Phillips, Poinsett and 1 more | 7 hr |
| Mar 27, 2:16 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 26 more | 89 min |
| Mar 27, 3:25 PM CDT | Tornado Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 31 more | 10 hr |
| Mar 27, 2:05 AM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Coahoma, DeSoto, Lafayette, Marshall and 8 more | 115 min |
| Mar 27, 3:56 PM CDT | Mesoscale Discussion | SPC | Attala, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 17 more | 94 min |
| Mar 27, 7:41 AM CDT | Mesoscale Discussion | SPC | Anderson, Bedford, Bledsoe, Campbell, Cannon, Claiborne and 28 more | 2 hr |
| Mar 27, 10:00 AM CDT | Mesoscale Discussion | SPC | Anderson, Blount, Campbell, Claiborne, Cocke, Grainger and 12 more | 90 min |
| Mar 27, 3:42 PM CDT | Mesoscale Discussion | SPC | Chester, Crockett, Decatur, Fayette, Hardeman, Hardin and 12 more | 93 min |
| Mar 27, 4:34 PM CDT | Mesoscale Discussion | SPC | Anderson, Brazos, Freestone, Henderson, Hopkins, Houston and 9 more | 116 min |
Nearby
Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Texas, 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.