Alert archive / Iowa / Mesoscale Discussions in 2015

Mesoscale Discussion 1539

July 25, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Jul 25, 2015, 10:54 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 25, 2015, 10:54 PM CDT (03:54 UTC)
Expired
Jul 26, 2015, 1:00 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 33 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Humboldt County, IA, Kossuth County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sioux County, IA, Cottonwood County, MN, Jackson County, MN, Martin County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Cedar County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Hutchinson County, SD, Lincoln County, SD, McCook County, SD, Minnehaha County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 65 km from the middle of the area, began a volume at 03:56 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, 3.9 hours before the alert went out and 215 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 2015-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 698 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 2015-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 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
698 J/kg
Mixed-layer CIN
-124 J/kg
Mixed-layer LCL
1049 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 25, 9:32 PM CDTSevere Thunderstorm WatchSPCDickinson, Lyon, Osceola3 hr
Jul 26, 1:13 AM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Bremer, Buena Vista, Butler and 40 more3 hr
Jul 26, 1:30 PM CDTMesoscale DiscussionSPCArthur, Chase, Cheyenne, Deuel, Garden, Grant and 4 more2 hr
Jul 26, 2:07 PM CDTSevere Thunderstorm WatchSPCArthur, Banner, Box Butte, Chase, Cherry, Cheyenne and 21 more9 hr
Jul 26, 5:22 PM CDTMesoscale DiscussionSPCArthur, Blaine, Box Butte, Brown, Chase, Cherry and 20 more83 min
Jul 26, 2:07 PM CDTMesoscale DiscussionSPCJackson, Meade, Oglala Lakota, Pennington83 min

Nearby

Mesoscale Discussions in Iowa, 2015Mesoscale Discussions in South Dakota, 2015Mesoscale Discussions in Minnesota, 2015Every mesoscale discussion in 2015

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.