Alert archive / Minnesota / Mesoscale Discussions in 2018

Mesoscale Discussion 1021

July 8, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2018, 7:58 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 8, 2018, 7:58 PM CDT (00:58 UTC)
Expired: Jul 8, 2018, 10:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 58 counties

Aitkin County, MN, Anoka County, MN, Becker County, MN, Benton County, MN, Big Stone County, MN, Carlton County, MN, Cass County, MN, Chippewa County, MN, Chisago County, MN, Clay County, MN, Cook County, MN, Crow Wing County, MN, Douglas County, MN, Grant County, MN, Hubbard County, MN, Isanti County, MN, Itasca County, MN, Kanabec County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Lake County, MN, Meeker County, MN, Mille Lacs County, MN, Morrison County, MN, Otter Tail County, MN, Pine County, MN, Pope County, MN, Saint Louis County, MN, Sherburne County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Traverse County, MN, Wadena County, MN, Wilkin County, MN, Wright County, MN, Dickey County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Brown County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Marshall County, SD, Roberts County, SD, Spink County, SD, Ashland County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Iron County, WI, Polk County, WI, Sawyer County, WI, Washburn County, WI

The radar

The Duluth radar (KDLH), 95 km from the middle of the area, began a volume at 00:57 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, 1.0 hours before the alert went out and 197 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 95 J/kg
Mixed-layer CIN: -247 J/kg
Mixed-layer LCL: 1776 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 100 m²/s²
0-3 km storm-relative helicity: 175 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

740 
ACUS11 KWNS 090058
SWOMCD
SPC MCD 090058 
MIZ000-MNZ000-WIZ000-SDZ000-NDZ000-090300-

Mesoscale Discussion 1021
NWS Storm Prediction Center Norman OK
0758 PM CDT Sun Jul 08 2018

Areas affected...Southeast North Dakota...Northeast South
Dakota...portions of central Minnesota...far northwest Wisconsin

Concerning...Severe Thunderstorm Watch 267...

Valid 090058Z - 090300Z

The severe weather threat for Severe Thunderstorm Watch 267
continues.

SUMMARY...A threat for isolated severe wind and hail will persist
for the next few hours. The areas of greatest risk will be in
southeast North Dakota, northeast South Dakota, and parts of
west-central Minnesota, with diminishing risk in eastern portions of
WW 267.

DISCUSSION...Over the past hour, 1 km radar mosaic imagery has shown
that storms within WW 267 have congealed and become increasingly
linear in a west-to-east oriented band. The area of greatest threat
for severe wind and hail is in far southeast North Dakota and
northeast South Dakota. The 00Z ABR sounding shows greater than 2500
J/kg MLCAPE with a long hodograph through 6 km. 0-3 km hodograph
curvature is moderate -- with around 250 m2/s2 effective SRH -- but
the linear storm mode should temper the tornado threat. Farther to
the east/southeast, substantial convective inhibition is present per
the 00Z MPX sounding. Even with 35-40 kts of effective 0-6 km shear,
the linear storm mode should limit severe hail and severe wind to
isolated coverage. Should any severe threat persist, local
extensions may be needed.

..Wendt.. 07/09/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MQT...DLH...MPX...FGF...ABR...BIS...

LAT...LON   46059018 45059382 44719653 44749822 45219870 45949897
            46729788 47159572 47729256 47969061 48008948 47998941
            47968941 47968941 47968941 47958943 46059018

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 9, 5:48 PM CDT	Mesoscale Discussion	SPC	Billings, Burke, Divide, Dunn, Golden Valley, McKenzie and 5 more	117 min
Jul 9, 5:41 AM CDT	Mesoscale Discussion	SPC	Oglala Lakota, Pennington	64 min

Nearby

Mesoscale Discussions in Minnesota, 2018 Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in Wisconsin, 2018 Every mesoscale discussion in 2018

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.