Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 876

June 25, 201820 counties in Iowa; 5 counties in Missouri; 17 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 25, 2018, 5:14 PM CDT for 20 counties in Iowa; 5 counties in Missouri; 17 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 25, 2018, 5:14 PM CDT (22:14 UTC)
Expired
Jun 25, 2018, 7:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 42 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Fremont County, IA, Guthrie County, IA, Lucas County, IA, Madison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Atchison County, MO, Harrison County, MO, Mercer County, MO, Nodaway County, MO, Worth County, MO, Butler County, NE, Cass County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Polk County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 106 km from the middle of the area, began a volume at 22:15 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.2 hours before the alert went out and 106 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 2018-06-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 118 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 2018-06-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -89 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
118 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
796 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-89 m²/s²
0-3 km storm-relative helicity
-80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 25, 5:40 PM CDTTornado WatchSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 13 more3 hr
Jun 25, 3:34 AM CDTMesoscale DiscussionSPCJasper, McDonald, Newton86 min
Jun 25, 3:23 PM CDTMesoscale DiscussionSPCAudrain, Boone, Callaway, Cape Girardeau, Cole, Cooper and 27 more97 min
Jun 24, 7:51 PM CDTMesoscale DiscussionSPCFranklin, Webster84 min

Nearby

Mesoscale Discussions in Iowa, 2018Mesoscale Discussions in Nebraska, 2018Mesoscale Discussions in Missouri, 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.