Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1336
The Storm Prediction Center issued this mesoscale discussion at Jul 23, 2021, 9:07 PM CDT for 8 counties in Minnesota; 17 counties in South Dakota. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2021, 9:07 PM CDT (02:07 UTC)
- Expired
- Jul 23, 2021, 11:30 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 25 counties
Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Pipestone County, MN, Redwood County, MN, Rock County, MN, Yellow Medicine County, MN, Aurora County, SD, Beadle County, SD, Brookings County, SD, Davison County, SD, Deuel County, SD, Douglas County, SD, Hamlin County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD
The radar
The Sioux Falls radar (KFSD), 62 km from the middle of the area, began a volume at 02:08 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 00:00Z, 2.1 hours before the alert went out and 136 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
- 3002 J/kg
- Mixed-layer CIN
- -46 J/kg
- Mixed-layer LCL
- 1613 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 53 m²/s²
- 0-3 km storm-relative helicity
- 89 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 6.9
The text
As transmitted.
861
ACUS11 KWNS 240208
SWOMCD
SPC MCD 240207
MNZ000-SDZ000-240430-
Mesoscale Discussion 1336
NWS Storm Prediction Center Norman OK
0907 PM CDT Fri Jul 23 2021
Areas affected...eastern South Dakota into southwest Minnesota
Concerning...Severe potential...Watch unlikely
Valid 240207Z - 240430Z
Probability of Watch Issuance...20 percent
SUMMARY...Clusters of storms will move from South Dakota into
Minnesota, possibly with strong gust potential.
DISCUSSION...Sporadic storms have developed within a broad band of
precipitation extending from north-central NE into eastern SD.
Despite cooler boundary-layer temperatures, robust moisture is in
place with PWAT over 2.00" measured on GPS sensors near FSD.
Warmer midlevel temperatures exist in this region compared to
farther north, which is hampering hail potential. In addition,
deep-layer shear is less with only 25-30 kt winds at 500 mb. Despite
this, a growing cluster of storms may be able to produce strong,
water-loaded downdrafts, as instability remains favorable downstream
into MN. Convective trends will continue to be monitored for upscale
growth that may necessitate watch consideration.
..Jewell/Edwards.. 07/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...FSD...ABR...
LAT...LON 43379743 43259832 43439886 43829913 44209909 44579855
44819762 45079593 44859553 44449524 43999528 43689585
43569655 43379743SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 7:44 PM CDT | Mesoscale Discussion | SPC | Aitkin, Carlton, Cass, Lake, Saint Louis | 2 hr |
| Jul 23, 10:33 PM CDT | Mesoscale Discussion | SPC | Big Stone, Clay, Grant, Otter Tail, Stevens, Traverse and 1 more | 117 min |
| Jul 23, 11:22 PM CDT | Severe Thunderstorm Watch | SPC | Anoka, Benton, Big Stone, Chippewa, Douglas, Grant and 16 more | 4 hr |
| Jul 24, 1:10 AM CDT | Mesoscale Discussion | SPC | Big Stone, Chippewa, Douglas, Grant, Kandiyohi, Meeker and 9 more | 95 min |
| Jul 23, 7:02 PM CDT | Severe Thunderstorm Watch | SPC | Brown, Campbell, Clark, Codington, Corson, Day and 15 more | 7 hr |
Nearby
Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in Minnesota, 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.