Alert archive / Minnesota / Mesoscale Discussions in 2022
Mesoscale Discussion 1621
The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2022, 4:20 PM CDT for 42 counties in Minnesota; 7 counties in Wisconsin. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Jul 31, 2022, 4:20 PM CDT (21:20 UTC)
- Expired
- Jul 31, 2022, 6:15 PM CDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 49 counties
Anoka County, MN, Benton County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Chisago County, MN, Cottonwood County, MN, Crow Wing County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Isanti County, MN, Jackson County, MN, Kanabec County, MN, Kandiyohi County, MN, Le Sueur County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Mille Lacs County, MN, Morrison County, MN, Mower County, MN, Nicollet County, MN, Olmsted County, MN, Pine County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sherburne County, MN, Sibley County, MN, Stearns County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Wright County, MN, Barron County, WI, Burnett County, WI, Dunn County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Saint Croix County, WI
The radar
The Minneapolis radar (KMPX), 24 km from the middle of the area, began a volume at 21:20 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
Minneapolis, MN (KMPX), launched 12:00Z, 9.3 hours before the alert went out and 21 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1324 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 90 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
707
ACUS11 KWNS 312120
SWOMCD
SPC MCD 312120
MNZ000-WIZ000-312315-
Mesoscale Discussion 1621
NWS Storm Prediction Center Norman OK
0420 PM CDT Sun Jul 31 2022
Areas affected...Parts of central/southern MN into western WI
Concerning...Severe potential...Watch possible
Valid 312120Z - 312315Z
Probability of Watch Issuance...40 percent
SUMMARY...Severe risk could be increasing across parts of
central/southern Minnesota into western Wisconsin this
afternoon/early evening. The primary concerns are locally severe
gusts and sporadic large hail. Trends are being monitored for a
possible watch.
DISCUSSION...In the wake of earlier warm-advection-driven elevated
convection, pockets of diurnal destabilization are evident in
visible satellite imagery across parts of central/southern MN into
western WI -- characterized by a transition from stable billow
clouds to horizontal convective rolls. Given this gradual
destabilization of a moist boundary layer (upper 60s/lower 70s
dewpoints), new convective development will be possible along/ahead
of a cold front across west/central MN. The plume of warm advection
is contributing to modest low-level hodograph curvature (near 100
m2/s2 SRH), and effective bulk shear of 30-40 kt would conditionally
support organized convective structures including supercells.
If convection can maintain residence time in the pockets of
surface-based instability across the warm sector, locally severe
gusts and sporadic large hail would be possible, and a brief tornado
cannot be ruled out owing to the modest boundary-layer streamwise
vorticity. Convective trends are being monitored for a possible
watch issuance.
..Weinman/Hart.. 07/31/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DLH...ARX...MPX...FSD...
LAT...LON 46139452 45649498 44799541 44489551 43879537 43579521
43579478 43549425 43559294 43649233 44119190 44929171
45989192 46399224 46539412 46139452Nearby
Mesoscale Discussions in Minnesota, 2022Mesoscale Discussions in Wisconsin, 2022Every mesoscale discussion in 2022
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.