Alert archive / Arkansas / Mesoscale Discussions in 2021

Mesoscale Discussion 1862

October 15, 20216 counties in Arkansas; 4 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Oct 15, 2021, 4:12 AM CDT for 6 counties in Arkansas; 4 counties in Oklahoma. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Oct 15, 2021, 4:12 AM CDT (09:12 UTC)
Expired: Oct 15, 2021, 5:45 AM CDT
In force: 93 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

Counties Crawford County, AR, Franklin County, AR, Johnson County, AR, Madison County, AR, Newton County, AR, Washington County, AR, Adair County, OK, Cherokee County, OK, Muskogee County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 40 km from the middle of the area, began a volume at 09:15 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, 9.2 hours before the alert went out and 147 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 130 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 513 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

315 
ACUS11 KWNS 150912
SWOMCD
SPC MCD 150912 COR
ARZ000-OKZ000-151045-

Mesoscale Discussion 1862
NWS Storm Prediction Center Norman OK
0412 AM CDT Fri Oct 15 2021

Areas affected...portions of eastern OK into northwest AR

Concerning...Severe potential...Watch unlikely 

Valid 150912Z - 151045Z

CORRECTED FOR MISSING STATE ID IN SUMMARY

Probability of Watch Issuance...20 percent

SUMMARY...A couple of strong to locally damaging gusts are possible
over parts of eastern OK into northwest AR early this morning. The
overall threat is expected to remain marginal and sporadic,
precluding the need for a watch at this time.

DISCUSSION...A well-organized bow continues to shift eastward across
eastern OK early this morning. Radar data from KSRX indicates a
broad, well-defined rear-inflow jet. At least weak low-level
inhibition exists across the region, and convection appears to be
somewhat elevated based on mostly sub-severe measured gusts from
regional OK Mesonet and other observation sites. However, a narrow
corridor of weak instability, along with strong vertical shear, is
maintaining the bow. A measured gust of 61 mph in McIntosh County
around 30 minutes ago suggests at least some localized threat for a
couple of marginally severe wind gusts could persist downstream into
parts of northwest AR over the next couple of hours.

..Leitman/Edwards.. 10/15/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LZK...TSA...

LAT...LON   35229495 35299549 35629544 35889540 36089496 36229427
            36319355 36249318 35959305 35719314 35469335 35369373
            35309413 35249450 35249478 35229495

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 15, 11:14 AM CDT	Mesoscale Discussion	SPC	Arkansas, Clay, Craighead, Crittenden, Cross, Faulkner and 16 more	3 hr
Oct 15, 12:28 PM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Clark, Clay, Cleburne, Cleveland, Conway and 33 more	9 hr
Oct 15, 2:52 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Craighead, Crittenden, Cross, Dallas and 19 more	113 min
Oct 14, 9:46 PM CDT	Mesoscale Discussion	SPC	Caddo, Canadian, Cleveland, Creek, Grady, Lincoln and 6 more	2 hr

Nearby

Mesoscale Discussions in Arkansas, 2021 Mesoscale Discussions in Oklahoma, 2021 Every 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.