Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 108
The Storm Prediction Center issued this mesoscale discussion at Feb 17, 2021, 9:15 AM CST for 4 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 17, 2021, 9:15 AM CST (15:15 UTC)
- Expired
- Feb 17, 2021, 3:15 PM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Heavy snow
All 47 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, Desha County, AR, Drew County, AR, Garland 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, Monroe County, AR, Nevada County, AR, Ouachita County, AR, Phillips County, AR, Pike County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Bolivar County, MS, Coahoma County, MS, DeSoto County, MS, Marshall County, MS, Panola County, MS, Quitman County, MS, Tate County, MS, Tunica County, MS, Fayette County, TN, Shelby County, TN, Tipton County, TN, Bowie County, TX, Cass County, TX
The radar
The Little Rock radar (KLZK), 74 km from the middle of the area, began a volume at 15:12 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 12:00Z, 3.3 hours before the alert went out and 203 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 693 m above ground
- 0-6 km bulk shear
- 67 kt
- 0-1 km storm-relative helicity
- 304 m²/s²
- 0-3 km storm-relative helicity
- 342 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
466
ACUS11 KWNS 171516
SWOMCD
SPC MCD 171515
TNZ000-MSZ000-ARZ000-LAZ000-TXZ000-172115-
Mesoscale Discussion 0108
NWS Storm Prediction Center Norman OK
0915 AM CST Wed Feb 17 2021
Areas affected...the ArkLaTex region northeastward to southwest
Tennessee
Concerning...Heavy snow
Valid 171515Z - 172115Z
SUMMARY...A band of moderate to occasionally heavy snow will
continue to expand northeastward across the discussion area,
potentially impacting the Memphis, TN metropolitan area beginning
around 17Z.
DISCUSSION...Precipitation continues to expand on the northern flank
of a precipitation shield covering much of east Texas and western
Louisiana currently. Over the past hour, precipitation (falling
mostly as moderate snow) has expanded in coverage and intensified
across southeastern Arkansas near Pine Bluff/Dumas and vicinity.
The overall regime will favor continued expansion of the
precipitation into southwest Tennessee and northwestern Mississippi,
with the onset of snowfall in the Memphis, TN metro area around 17Z.
Several hours of moderate to occasionally heavy snow will occur in
this region through at least 21Z. Point forecast soundings indicate
potential for some sleet to mix in with the snow across southern
portions of the MD area (generally from Texarkana to Bolivar County,
MS). Occasional 1" per hour rates are expected - especially in
areas that maintain an all-snow precipitation type.
..Cook.. 02/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...JAN...LZK...SHV...
LAT...LON 33279461 33939419 34999284 35349159 35679002 35718943
35388905 34758926 34069006 33609128 33099318 32809404
32909431 33279461SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 17, 10:53 AM CST | Mesoscale Discussion | SPC | Ashley, Chicot | 6 hr |
| Feb 17, 3:22 PM CST | Mesoscale Discussion | SPC | Arkansas, Calhoun, Clark, Cleveland, Crittenden, Cross and 23 more | 4 hr |
| Feb 17, 1:00 PM CST | Mesoscale Discussion | SPC | Alcorn, Benton, Itawamba, Lafayette, Lee, Marshall and 6 more | 3 hr |
| Feb 17, 5:38 PM CST | Mesoscale Discussion | SPC | Harrison | 3 hr |
| Feb 16, 6:59 PM CST | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 7 more | 4 hr |
| Feb 16, 8:14 PM CST | Mesoscale Discussion | SPC | Archer, Clay, Cooke, Grayson, Jack, Montague and 2 more | 4 hr |
| Feb 16, 9:41 PM CST | Mesoscale Discussion | SPC | Bell, Brazos, Burleson, Burnet, Falls, Lampasas and 5 more | 4 hr |
| Feb 17, 1:55 AM CST | Mesoscale Discussion | SPC | Angelina, Austin, Bastrop, Brazos, Burleson, Colorado and 31 more | 6 hr |
| Feb 17, 7:38 AM CST | Mesoscale Discussion | SPC | Jasper, Newton, Sabine | 4 hr |
Nearby
Mesoscale Discussions in Arkansas, 2021Mesoscale 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.