Alert archive / Minnesota / Mesoscale Discussions in 2018

Mesoscale Discussion 1049

July 12, 2018Dickinson County, Lyon County, Osceola County, Iowa; 19 counties in Minnesota; 19 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 12, 2018, 9:39 PM CDT for Dickinson County, Lyon County, Osceola County, Iowa; 19 counties in Minnesota; 19 counties in Wisconsin. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Jul 12, 2018, 9:39 PM CDT (02:39 UTC)
Expired
Jul 12, 2018, 11:15 PM CDT
In force
96 min
Issued by
the Storm Prediction Center
All 41 counties

Dickinson County, IA, Lyon County, IA, Osceola County, IA, Blue Earth County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Nobles County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Clark County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Marathon County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Portage County, WI, Shawano County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Waupaca County, WI, Waushara County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 61 km from the middle of the area, began a volume at 02:43 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, 2.7 hours before the alert went out and 163 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2018-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 487 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2018-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -75 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
487 J/kg
Mixed-layer CIN
-170 J/kg
Mixed-layer LCL
876 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-75 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

062 
ACUS11 KWNS 130240
SWOMCD
SPC MCD 130239 
WIZ000-MNZ000-IAZ000-SDZ000-130415-

Mesoscale Discussion 1049
NWS Storm Prediction Center Norman OK
0939 PM CDT Thu Jul 12 2018

Areas affected...southern MN into central WI

Concerning...Severe Thunderstorm Watch 274...275...

Valid 130239Z - 130415Z

The severe weather threat for Severe Thunderstorm Watch 274, 275
continues.

SUMMARY...A few strong wind gusts may be possible for another hour
or two as gradual weakening trend ensues this evening. Additional
downstream watches are not expected.

DISCUSSION...Portions of the line of storms tracking east/southeast
across western into central WI have weakened this evening. Embedded
cells occasionally have increased in intensity, but overall trends
suggest storms are struggling to maintain intensity as boundary
layer stabilization continues due to loss of heating and as storms
shift away from stronger deep layer shear. While some strong gusts
may persist another hour or two, downstream watches are not expected
and existing watch may be canceled prior to expiration.

..Leitman.. 07/13/2018

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

ATTN...WFO...GRB...MKX...ARX...MPX...DMX...FSD...

LAT...LON   43539174 43309620 43389656 43759617 45349011 45238885
            44778859 44168887 43658986 43539174

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 13, 12:41 PM CDTMesoscale DiscussionSPCBlack Hawk, Bremer, Butler, Calhoun, Cerro Gordo, Chickasaw and 16 more94 min
Jul 13, 3:54 PM CDTSevere Thunderstorm WatchSPCAllamakee, Buchanan, Chickasaw, Clayton, Delaware, Dubuque and 3 more6 hr
Jul 13, 6:23 PM CDTMesoscale DiscussionSPCClinton, Delaware, Dubuque, Jackson, Jones2 hr
Jul 12, 7:35 PM CDTMesoscale DiscussionSPCBlue Earth, Brown, Carver, Cottonwood, Dakota, Dodge and 18 more85 min
Jul 12, 8:14 PM CDTSevere Thunderstorm WatchSPCLanglade, Lincoln, Marathon, Menominee, Portage, Shawano and 3 more2 hr

Nearby

Mesoscale Discussions in Minnesota, 2018Mesoscale Discussions in Wisconsin, 2018Mesoscale Discussions in Iowa, 2018Every 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.