Alert archive / Iowa / Mesoscale Discussions in 2021
Mesoscale Discussion 179
The Storm Prediction Center issued this mesoscale discussion at Mar 15, 2021, 1:50 AM CDT for 44 counties in Iowa; 21 counties in Minnesota; 15 counties in South Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 15, 2021, 1:50 AM CDT (06:50 UTC)
- Expired
- Mar 15, 2021, 7:45 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Heavy snow
All 80 counties
Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Marshall County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Sioux County, IA, Story County, IA, Tama County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Pipestone County, MN, Redwood County, MN, Renville County, MN, Rock County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Yellow Medicine County, MN, Brookings County, SD, Clark County, SD, Codington County, SD, Deuel County, SD, Hamlin County, SD, Hanson County, SD, Kingsbury County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD
The radar
The Sioux Falls radar (KFSD), 140 km from the middle of the area, began a volume at 06:50 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 00:00Z, 6.8 hours before the alert went out and 226 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
- 2281 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- 14 m²/s²
- 0-3 km storm-relative helicity
- 8 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
136
ACUS11 KWNS 150651
SWOMCD
SPC MCD 150650
IAZ000-MNZ000-SDZ000-151245-
Mesoscale Discussion 0179
NWS Storm Prediction Center Norman OK
0150 AM CDT Mon Mar 15 2021
Areas affected...Portions of eastern SD...southern MN...and
northern/central IA
Concerning...Heavy snow
Valid 150650Z - 151245Z
SUMMARY...Moderate to heavy snow, with peak rates of 1-2 inches per
hour, will likely continue this morning.
DISCUSSION...A large, closed upper low will move slowly eastward
across the central Plains early this morning. A swath of
precipitation ongoing within the warm/moist low-level conveyor east
of this cyclone is expected to continue across parts of the northern
Plains and Upper Midwest. Although surface temperatures are marginal
(generally 32-36 F), cooling at mid levels and strong ascent within
the saturated dendritic growth zone will occur as the upper low
approaches. Predominant precipitation type across southern MN and
central IA should become snow over the next couple of hours as this
process occurs. Within the band of heaviest precipitation, snowfall
rates of 1-2 inches per hour appear likely. This band is expected to
slowly shift eastward across eastern SD, southern MN, and
northern/central IA through the early morning hours. Some mixed
precipitation may occur on the southern fringe of the band in
central IA, where the temperature profile in the boundary layer will
be very near freezing.
..Gleason.. 03/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX...ABR...
LAT...LON 42489637 43479766 44059807 44839799 45079705 44789469
44069324 42959170 42219179 41869266 41769373 41879471
42009556 42489637Nearby
Mesoscale Discussions in Iowa, 2021Mesoscale 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.