Alert archive / Iowa / Mesoscale Discussions in 2015

Mesoscale Discussion 1650

August 8, 201513 counties in Iowa; 4 counties in Missouri; 7 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 8, 2015, 8:36 PM CDT for 13 counties in Iowa; 4 counties in Missouri; 7 counties in Nebraska. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Aug 8, 2015, 8:36 PM CDT (01:36 UTC)
Expired: Aug 8, 2015, 10:30 PM CDT
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 24 counties

Adair County, IA, Adams County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Atchison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Cass County, NE, Johnson County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Sarpy County, NE

The radar

The Omaha radar (KOAX), 140 km from the middle of the area, began a volume at 01:36 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.

Severe Thunderstorm Watch 482Aug 8, 8:50 PM CDT

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.6 hours before the alert went out and 140 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 430 J/kg
Mixed-layer CIN: -176 J/kg
Mixed-layer LCL: 1221 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 277 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.2

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.

Issued	Product	Office	Counties	Lasted
Aug 8, 8:51 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Cass, Clarke, Decatur, Fremont and 10 more	6 hr
Aug 8, 11:11 PM CDT	Mesoscale Discussion	SPC	Adams, Clarke, Decatur, Fremont, Montgomery, Page and 3 more	94 min
Aug 9, 1:37 AM CDT	Mesoscale Discussion	SPC	Adams, Appanoose, Cass, Clarke, Davis, Decatur and 8 more	83 min
Aug 9, 1:05 PM CDT	Mesoscale Discussion	SPC	Cherokee, Lyon, Monona, O'Brien, Osceola, Plymouth and 2 more	115 min
Aug 9, 1:42 PM CDT	Severe Thunderstorm Watch	SPC	Cherokee, Ida, Lyon, O'Brien, Osceola, Plymouth and 2 more	9 hr
Aug 9, 4:03 PM CDT	Mesoscale Discussion	SPC	Cherokee, Ida, Lyon, O'Brien, Osceola, Plymouth and 2 more	117 min
Aug 9, 3:55 PM CDT	Mesoscale Discussion	SPC	Benton, Bollinger, Boone, Callaway, Camden, Cape Girardeau and 40 more	2 hr
Aug 9, 5:45 PM CDT	Severe Thunderstorm Watch	SPC	Crawford, Dent, Franklin, Gasconade, Iron, Jefferson and 9 more	4 hr

Nearby

Mesoscale Discussions in Iowa, 2015 Mesoscale Discussions in Nebraska, 2015 Mesoscale Discussions in Missouri, 2015 Every 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.