Alert archive / North Dakota / Mesoscale Discussions in 2021

Mesoscale Discussion 1854

October 13, 20215 counties in North Dakota; 5 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Oct 13, 2021, 3:10 PM CDT for 5 counties in North Dakota; 5 counties in South Dakota. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Oct 13, 2021, 3:10 PM CDT (20:10 UTC)
Expired: Oct 13, 2021, 4:15 PM CDT
In force: 65 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

Counties Dickey County, ND, LaMoure County, ND, McIntosh County, ND, Ransom County, ND, Sargent County, ND, Brown County, SD, Edmunds County, SD, Marshall County, SD, McPherson County, SD, Roberts County, SD

The radar

The Aberdeen radar (KABR), 34 km from the middle of the area, began a volume at 20:10 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

Aberdeen, SD (KABR), launched 12:00Z, 8.2 hours before the alert went out and 92 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 913 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 252 m²/s²
0-3 km storm-relative helicity: 334 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

258 
ACUS11 KWNS 132011
SWOMCD
SPC MCD 132010 
MNZ000-SDZ000-NDZ000-132115-

Mesoscale Discussion 1854
NWS Storm Prediction Center Norman OK
0310 PM CDT Wed Oct 13 2021

Areas affected...Portions of North and South Dakota

Concerning...Severe potential...Watch unlikely 

Valid 132010Z - 132115Z

Probability of Watch Issuance...5 percent

SUMMARY...A low-end risk for a tornado will be be possible this
afternoon. Given the nature of the threat a watch is unlikely.

DISCUSSION...As of 1955 UTC, regional WV imagery showed a deep
vertically stacked low was located across western SD. To the north
and east of the low, satellite imagery showed clearing taking place
across the ND/SD border. Diurnal heating is supporting weak
destabilization within the narrow zone ahead of the surface
cold/occluded front. Towering cumulus should evolve into an arc of
low topped thunderstorms this afternoon. Model soundings show steep
low-level lapse rate with 0-3 km MLCAPE in excess of 100 J/kg. With
abundant vertical vorticity close to the low center, a few weakly
rotating storms may have the potential to produce a brief weak
tornado. Given the small spatial and temporal severe risk, a watch
is unlikely.

..Lyons/Mosier.. 10/13/2021

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

ATTN...WFO...FGF...ABR...BIS...

LAT...LON   45229675 45319717 45599762 45599817 45519860 45329903
            45289924 45339949 45599968 45969974 46209968 46589913
            46679836 46559756 45889679 45749677 45379672 45229675

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 13, 4:58 AM CDT	Mesoscale Discussion	SPC	Bowman, Golden Valley	6 hr

Nearby

Mesoscale Discussions in North Dakota, 2021 Mesoscale Discussions in South Dakota, 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.