Alert archive / Iowa / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 459

July 28, 20154 states

The Storm Prediction Center issued this severe thunderstorm watch at Jul 28, 2015, 5:46 PM CDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jul 28, 2015, 5:46 PM CDT (22:46 UTC)
Expired: Jul 29, 2015, 12:00 AM CDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 66 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Fremont County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Montgomery County, IA, Muscatine County, IA, Page County, IA, Poweshiek County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Atchison County, KS, Brown County, KS, Clay County, KS, Dickinson County, KS, Doniphan County, KS, Geary County, KS, Jackson County, KS, Marshall County, KS, Morris County, KS, Nemaha County, KS, Pottawatomie County, KS, Riley County, KS, Wabaunsee County, KS, Adair County, MO, Andrew County, MO, Atchison County, MO, Clark County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO, Worth County, MO, Johnson County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE

The radar

The Des Moines radar (KDMX), 94 km from the middle of the area, began a volume at 22:47 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

22 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 28, 5:50 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Marion	40 min
Jul 28, 6:07 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Monroe, Wapello	38 min
Jul 28, 6:34 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska	27 min
Jul 28, 6:38 PM CDT	Severe Thunderstorm Warning	DMX	Wapello	52 min
Jul 28, 6:39 PM CDT	Severe Thunderstorm Warning	DVN	Jefferson, Keokuk, Washington	66 min
Jul 28, 6:49 PM CDT	Severe Thunderstorm Warning	OAX	Montgomery	26 min
Jul 28, 6:57 PM CDT	Severe Thunderstorm Warning	EAX	Atchison	33 min
Jul 28, 7:18 PM CDT	Severe Thunderstorm Warning	DMX	Wapello	18 min
Jul 28, 7:35 PM CDT	Flash Flood Warning	DMX	Madison, Marion, Warren	6 hr
Jul 28, 8:10 PM CDT	Severe Thunderstorm Warning	DMX	Marion, Warren	50 min
Jul 28, 8:37 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Marion, Monroe, Warren	53 min
Jul 28, 9:04 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Lucas, Monroe, Wayne	41 min
Jul 28, 9:26 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Lucas, Wayne	39 min
Jul 28, 9:35 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis, Lucas, Monroe, Wayne	70 min
Jul 28, 9:40 PM CDT	Severe Thunderstorm Warning	EAX	Mercer, Putnam	36 min
Jul 28, 10:03 PM CDT	Severe Thunderstorm Warning	DMX	Davis, Monroe, Wapello	42 min
Jul 28, 10:14 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold, Taylor	35 min
Jul 28, 10:15 PM CDT	Flash Flood Warning	DMX	Adams, Taylor	6 hr
Jul 28, 11:11 PM CDT	Flash Flood Warning	EAX	Nodaway, Worth	6 hr
Jul 28, 11:36 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	39 min
Jul 28, 11:38 PM CDT	Flash Flood Warning	DMX	Wayne	6 hr
Jul 28, 11:52 PM CDT	Severe Thunderstorm Warning	EAX	Mercer, Putnam, Sullivan	53 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Topeka, KS (KFOE), launched 12:00Z, 10.8 hours before the alert went out and 271 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: 721 J/kg
Mixed-layer CIN: -285 J/kg
Mixed-layer LCL: 1383 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -51 m²/s²
0-3 km storm-relative helicity: -37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 28, 1:57 AM CDT	Mesoscale Discussion	SPC	Lyon, Sioux	2 hr
Jul 28, 3:37 AM CDT	Mesoscale Discussion	SPC	Dickinson, Lyon, O'Brien, Osceola, Plymouth, Sioux	2 hr
Jul 28, 3:40 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Appanoose, Audubon, Cass, Clarke and 25 more	2 hr
Jul 28, 4:50 PM CDT	Mesoscale Discussion	SPC	Atchison, Barber, Barton, Brown, Clark, Clay and 30 more	2 hr
Jul 27, 9:41 PM CDT	Mesoscale Discussion	SPC	Boyd	3 hr
Jul 28, 12:38 AM CDT	Mesoscale Discussion	SPC	Arthur, Blaine, Brown, Custer, Garfield, Grant and 8 more	3 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2015 Severe Thunderstorm Watches in Missouri, 2015 Severe Thunderstorm Watches in Kansas, 2015 Every severe thunderstorm watch 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.