Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 1962
The Storm Prediction Center issued this mesoscale discussion at Dec 5, 2021, 11:17 PM CST for 15 counties in Arkansas; Howell County, Ozark County, Missouri; Sequoyah County, Oklahoma. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- Dec 5, 2021, 11:17 PM CST (05:17 UTC)
- Expired
- Dec 6, 2021, 1:15 AM CST
- In force
- 118 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 550
Counties Baxter County, AR, Boone County, AR, Crawford County, AR, Franklin County, AR, Fulton County, AR, Izard County, AR, Johnson County, AR, Logan County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Pope County, AR, Searcy County, AR, Sebastian County, AR, Washington County, AR, Howell County, MO, Ozark County, MO, Sequoyah County, OK
The radar
The Western Arkansas radar (KSRX), 99 km from the middle of the area, began a volume at 05:18 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
Springfield, MO (KSGF), launched 00:00Z, 5.3 hours before the alert went out and 115 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
- 125 J/kg
- Mixed-layer CIN
- -146 J/kg
- Mixed-layer LCL
- 1105 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 286 m²/s²
- 0-3 km storm-relative helicity
- 462 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
The text
As transmitted.
275 ACUS11 KWNS 060517 SWOMCD SPC MCD 060517 MOZ000-ARZ000-OKZ000-060715- Mesoscale Discussion 1962 NWS Storm Prediction Center Norman OK 1117 PM CST Sun Dec 05 2021 Areas affected...Eastern OK...Northern AR...Southern MO Concerning...Severe Thunderstorm Watch 550... Valid 060517Z - 060715Z The severe weather threat for Severe Thunderstorm Watch 550 continues. SUMMARY...Severe threat will steadily spread southeast across ww550. Wind and hail remain the primary threats. DISCUSSION...Squall line is in the process of maturing along the surging cold front over the Ozark Plateau into eastern OK. This band of convection has gradually solidified as it encounters higher PW and better instability. With deep-layer flow decidedly veered, it appears linear storm mode should be the primary concern. However, a few showers are noted ahead of the squall line across northwest AR and this activity does bear some watching. Given the lack of significant low-level convergence ahead of the cold front this activity may struggle to organize, though wind profiles do favor supercells. If the frontal bands remains the primary mode then wind/hail should continue to be the main threats. ..Darrow.. 12/06/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...TSA... LAT...LON 35379547 36349350 36899180 36329127 35049381 35379547
SPC 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 6, 3:01 AM CST | Mesoscale Discussion | SPC | Craighead, Crittenden, Cross, Faulkner, Garland, Jackson and 13 more | 59 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 Missouri, 2021Mesoscale Discussions in Oklahoma, 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.