Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 1420
The Storm Prediction Center issued this mesoscale discussion at Aug 5, 2021, 3:40 PM CDT for 6 counties in Minnesota; Brookings County, Deuel County, South Dakota. It was in force for 65 min.
The area
The outline as issued.
The facts
- Issued
- Aug 5, 2021, 3:40 PM CDT (20:40 UTC)
- Expired
- Aug 5, 2021, 4:45 PM CDT
- In force
- 65 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Chippewa County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Renville County, MN, Yellow Medicine County, MN, Brookings County, SD, Deuel County, SD
The radar
The Sioux Falls radar (KFSD), 133 km from the middle of the area, began a volume at 20:39 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, 8.7 hours before the alert went out and 182 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
- 370 J/kg
- Mixed-layer CIN
- -249 J/kg
- Mixed-layer LCL
- 1351 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 68 m²/s²
- 0-3 km storm-relative helicity
- 144 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
063 ACUS11 KWNS 052041 SWOMCD SPC MCD 052040 MNZ000-SDZ000-052145- Mesoscale Discussion 1420 NWS Storm Prediction Center Norman OK 0340 PM CDT Thu Aug 05 2021 Areas affected...east-central SD...southwest MN Concerning...Severe potential...Watch unlikely Valid 052040Z - 052145Z Probability of Watch Issuance...5 percent SUMMARY...A couple of strong thunderstorms may develop through the early evening near the SD/MN border. This activity will likely weaken after sunset. Marginal hail/localized gusty winds are the potential threats with these storms. DISCUSSION...Visible satellite imagery shows developing convection near the SD/MN border in the vicinity of a surface pressure trough/wind shift with a surface front accelerating south-southeastward towards the area. Surface conditions shows temperatures in the mid-upper 80s deg F with dewpoints in the mid 60s. Forecast soundings show steep 0-3 km lapse rates amidst generally modest westerly flow at or below 20 kt. Storm organization will be quite limited due to weak effective shear (below 20 kt) and favor multicellular activity. A marginal/localized risk for marginally severe hail or strong gusts could accompany the stronger storms through early evening. ..Smith/Grams.. 08/05/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FSD...ABR... LAT...LON 44879691 45219548 44729494 44319554 44209685 44879691
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in South 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.