Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1334
The Storm Prediction Center issued this mesoscale discussion at Jul 23, 2021, 5:04 PM CDT for 12 counties in North Dakota; 20 counties in South Dakota. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2021, 5:04 PM CDT (22:04 UTC)
- Expired
- Jul 23, 2021, 8:00 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 32 counties
Barnes County, ND, Cass County, ND, Dickey County, ND, Emmons County, ND, Grant County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Sargent County, ND, Sioux County, ND, Stutsman County, ND, Beadle County, SD, Brown County, SD, Butte County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Corson County, SD, Day County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Harding County, SD, Marshall County, SD, McPherson County, SD, Perkins County, SD, Potter County, SD, Spink County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Bismarck radar (KBIS), 151 km from the middle of the area, began a volume at 22:07 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
Bismarck Municip, ND (KBIS), launched 12:00Z, 10.1 hours before the alert went out and 151 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
- 108 J/kg
- Mixed-layer CIN
- -435 J/kg
- Mixed-layer LCL
- 1738 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 143 m²/s²
- 0-3 km storm-relative helicity
- 125 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
130
ACUS11 KWNS 232205
SWOMCD
SPC MCD 232204
SDZ000-NDZ000-240100-
Mesoscale Discussion 1334
NWS Storm Prediction Center Norman OK
0504 PM CDT Fri Jul 23 2021
Areas affected...southern North Dakota into northern South Dakota
Concerning...Severe potential...Watch possible
Valid 232204Z - 240100Z
Probability of Watch Issuance...60 percent
SUMMARY...Scattered storms are expected to form through evening,
either side of the North and South Dakota border. Large hail and
severe gusts will be possible.
DISCUSSION...Surface analysis shows a pressure trough from central
SD curling northeastward toward the Red River, with mid/upper 90s
temperatures common. A diffuse midlevel temperature gradient exists
across the Dakotas from north to south, with 500 mb temperatures to
-10 C near KBIS. Objective analysis indicates MLCAPE near 2000 J/kg,
with deep-layer shear approaching 50 kt.
Gradual height falls will occur through the evening, with increasing
northwesterly 850 mb winds developing from northwest to southeast
across the western Dakotas. Increasing lift may thus result in one
or more clusters of severe storms with east/southeast motion.
Isolated peak-heating storms may also form over northwest SD (west
of an extensive cloud deck), or near the Black Hills, with hail and
wind potential.
A watch could be required later this evening if it becomes apparent
severe storm coverage will be more than isolated.
..Jewell/Edwards.. 07/23/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...FSD...ABR...BIS...UNR...
LAT...LON 47019863 47099744 46849702 45789709 44809718 44549748
44399846 44639960 44910099 45010199 44990264 44820305
44540317 44140336 44130360 44470377 45350367 45610357
45760307 46470190 46880018 47019863SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 22, 9:04 PM CDT | Mesoscale Discussion | SPC | Burke, Divide, Williams | 116 min |
| Jul 23, 1:25 PM CDT | Mesoscale Discussion | SPC | Traill | 2 hr |
Nearby
Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in North Dakota, 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.