Alert archive / Iowa / Special Weather Statements in 2020

Special Weather Statement, NWS Des Moines, IA

March 28, 2020Mahaska County, Iowa

NWS Des Moines, IA issued this special weather statement at Mar 28, 2020, 4:56 AM CDT for Mahaska County, Iowa. It was in force for 19 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Mar 28, 2020, 4:56 AM CDT (09:56 UTC)
Expired: Mar 28, 2020, 5:15 AM CDT
In force: 19 min
Issued by: NWS Des Moines, IA

County Mahaska County, IA

The radar

The Des Moines radar (KDMX), 101 km from the middle of the area, began a volume at 09:59 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

Davenport, (KDVN), launched 00:00Z, 9.9 hours before the alert went out and 178 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: 4 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 610 m above ground
0-6 km bulk shear: 85 kt
0-1 km storm-relative helicity: 302 m²/s²
0-3 km storm-relative helicity: 512 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before this special weather statement went out at Mar 28, 3:57 AM CDT, 59 minutes earlier.

Area forecast discussion, Mar 28, 3:57 AM CDT, 59 minutes before

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Hazardous weather outlook, Mar 28, 3:30 AM CDT, 1 hour 26 minutes before

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In the hours before

Special weather statement, Mar 28, 4:56 AM CDT, 0 minutes before

Special Weather Statement
National Weather Service Des Moines IA
456 AM CDT Sat Mar 28 2020

IAZ075-281015-
Mahaska IA-
456 AM CDT Sat Mar 28 2020

...Up to Nickel Hail North of Oskaloosa...

At 455 AM CDT, Doppler radar was tracking a strong thunderstorm near
Oskaloosa, moving northeast at 55 mph.

Nickel size hail will be possible with this storm.

Locations impacted include...
North and northeast of Oskaloosa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4130 9272 4138 9277 4151 9241 4136 9241
TIME...MOT...LOC 0955Z 246DEG 48KT 4137 9265

Cogil

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 28, 1:07 AM CDT	Severe Thunderstorm Warning	DMX	Monroe, Wapello	23 min
Mar 28, 2:18 AM CDT	Dense Fog Advisory	DMX	Adair, Adams, Appanoose, Boone, Clarke, Dallas and 21 more	7 min
Mar 28, 2:28 AM CDT	Dense Fog Advisory	DMX	Adair, Adams, Appanoose, Boone, Clarke, Dallas and 21 more	9 hr
Mar 28, 2:59 AM CDT	Wind Advisory	DMX	Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more	34 hr
Mar 28, 9:55 AM CDT	River Flood Warning	DMX	Davis, Wapello	12 hr
Mar 28, 10:29 AM CDT	Special Weather Statement	DMX	Marion	46 min
Mar 28, 10:35 AM CDT	Special Weather Statement	DMX	Mahaska	40 min
Mar 28, 1:31 PM CDT	Special Weather Statement	DMX	Adams	44 min
Mar 28, 2:01 PM CDT	Special Weather Statement	DMX	Adair	44 min
Mar 28, 2:24 PM CDT	Tornado Warning Tornado observed	DMX	Adair, Guthrie, Madison	27 min
Mar 28, 3:49 PM CDT	Special Weather Statement	DMX	Hamilton, Wright	41 min
Mar 28, 3:51 PM CDT	Special Weather Statement	DMX	Hancock	39 min
Mar 28, 4:08 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Hamilton, Hancock, Wright	31 min
Mar 28, 4:10 PM CDT	Tornado Warning	DMX	Jasper, Marshall, Story	35 min
Mar 28, 4:38 PM CDT	Special Weather Statement	DMX	Hancock, Winnebago	37 min
Mar 28, 4:38 PM CDT	Tornado Warning	DMX	Marshall	22 min
Mar 28, 5:22 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Pocahontas, Webster	38 min
Mar 28, 5:54 PM CDT	Tornado Warning	DMX	Black Hawk	17 min
Mar 28, 6:02 PM CDT	Tornado Warning	DMX	Black Hawk	9 min

Nearby

Special Weather Statements in Iowa, 2020 Every special weather statement in 2020

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.