Alert archive / Iowa / Mesoscale Discussions in 2017

Mesoscale Discussion 1191

June 29, 20174 counties in Iowa; 4 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2017, 9:24 PM CDT for 4 counties in Iowa; 4 counties in Nebraska. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Jun 29, 2017, 9:24 PM CDT (02:24 UTC)
Expired
Jun 29, 2017, 10:30 PM CDT
In force
66 min
Issued by
the Storm Prediction Center

Counties Cass County, IA, Harrison County, IA, Mills County, IA, Pottawattamie County, IA, Douglas County, NE, Sarpy County, NE, Saunders County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 41 km from the middle of the area, began a volume at 02:23 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 00:00Z, 2.4 hours before the alert went out and 41 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 00:00Z on 2017-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1711 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 00:00Z on 2017-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.19395878Sfc1 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
1711 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
1380 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
81 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.6

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
Jun 29, 9:02 PM CDTSevere Thunderstorm WatchSPCFranklin, Harlan, Nuckolls, Thayer, Webster5 hr
Jun 30, 1:35 AM CDTMesoscale DiscussionSPCRichardson2 hr

Nearby

Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in Nebraska, 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.