Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 1086

July 19, 201819 counties in Iowa; Mercer County, Putnam County, Schuyler County, Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 19, 2018, 2:32 PM CDT for 19 counties in Iowa; Mercer County, Putnam County, Schuyler County, Missouri. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Jul 19, 2018, 2:32 PM CDT (19:32 UTC)
Expired
Jul 19, 2018, 4:30 PM CDT
In force
118 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 22 counties

Appanoose County, IA, Boone County, IA, Clarke County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Story County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Mercer County, MO, Putnam County, MO, Schuyler County, MO

The radar

The Des Moines radar (KDMX), 62 km from the middle of the area, began a volume at 19:34 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

Davenport, (KDVN), launched 12:00Z, 7.5 hours before the alert went out and 238 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, Davenport, at 12:00Z on 2018-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 2018-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1807 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
-21 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
Jul 19, 12:47 AM CDTMesoscale DiscussionSPCFremont, Mills118 min
Jul 19, 1:00 AM CDTSevere Thunderstorm WatchSPCFremont, Mills, Page5 hr
Jul 19, 1:27 PM CDTMesoscale DiscussionSPCHancock, Kossuth, Winnebago63 min
Jul 19, 3:11 PM CDTTornado WatchSPCAppanoose, Benton, Davis, Grundy, Hardin, Henry and 21 more6 hr
Jul 19, 5:18 PM CDTMesoscale DiscussionSPCAppanoose, Benton, Black Hawk, Cedar, Clinton, Davis and 27 more57 min
Jul 19, 6:26 PM CDTMesoscale DiscussionSPCDes Moines, Lee64 min
Jul 19, 3:52 AM CDTMesoscale DiscussionSPCAtchison, Holt53 min
Jul 19, 9:58 AM CDTMesoscale DiscussionSPCAndrew, Bates, Benton, Boone, Caldwell, Callaway and 45 more2 hr
Jul 19, 11:22 AM CDTSevere Thunderstorm WatchSPCBarry, Barton, Bates, Benton, Caldwell, Callaway and 47 more10 hr
Jul 19, 12:26 PM CDTSevere Thunderstorm WatchSPCPlatte8 hr
Jul 19, 2:15 PM CDTMesoscale DiscussionSPCBollinger, Butler, Carter, Christian, Dallas, Dent and 27 more2 hr
Jul 19, 2:43 PM CDTMesoscale DiscussionSPCPlatte92 min
Jul 19, 6:49 PM CDTSevere Thunderstorm WatchSPCKnox, Lewis, Lincoln, Marion, Pike, Ralls and 4 more7 hr

Nearby

Mesoscale Discussions in Iowa, 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.