Alert archive / Iowa / Mesoscale Discussions in 2017

Mesoscale Discussion 716

May 15, 201713 counties in Iowa; Jackson County, Nobles County, Rock County, Minnesota; 5 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 15, 2017, 9:15 AM CDT for 13 counties in Iowa; Jackson County, Nobles County, Rock County, Minnesota; 5 counties in South Dakota. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
May 15, 2017, 9:15 AM CDT (14:15 UTC)
Expired
May 15, 2017, 10:45 AM CDT
In force
90 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 21 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Lyon 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, Jackson County, MN, Nobles County, MN, Rock County, MN, Hutchinson County, SD, Lincoln County, SD, McCook County, SD, Minnehaha County, SD, Turner County, SD

The radar

The Sioux Falls radar (KFSD), 47 km from the middle of the area, began a volume at 14:15 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

Omaha, NE (KOAX), launched 12:00Z, 2.3 hours before the alert went out and 224 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, Omaha, NE at 12:00Z on 2017-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 527 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, Omaha, NE at 12:00Z on 2017-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
527 J/kg
Mixed-layer CIN
-402 J/kg
Mixed-layer LCL
1854 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 15, 3:48 PM CDTMesoscale DiscussionSPCBuena Vista, Butler, Calhoun, Carroll, Cerro Gordo, Chickasaw and 16 more87 min
May 15, 5:11 PM CDTSevere Thunderstorm WatchSPCAllamakee, Black Hawk, Bremer, Buchanan, Butler, Calhoun and 24 more9 hr
May 15, 4:07 PM CDTMesoscale DiscussionSPCButte, Custer, Fall River, Lawrence, Oglala Lakota, Pennington113 min
May 15, 5:40 PM CDTSevere Thunderstorm WatchSPCButte, Custer, Fall River, Harding, Lawrence, Meade and 3 more7 hr

Nearby

Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in South Dakota, 2017Mesoscale Discussions in Minnesota, 2017Every mesoscale discussion in 2017

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.