Alert archive / Iowa / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 22, NWS Des Moines, IA

May 16, 1999Boone County, Story County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 16, 1999, 10:12 AM CDT for Boone County, Story County, Iowa. It was in force for 33 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: May 16, 1999, 10:12 AM CDT (15:12 UTC)
Expired: May 16, 1999, 10:45 AM CDT
In force: 33 min
Issued by: NWS Des Moines, IA
Area: Whole counties

Counties Boone County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 34 km from the middle of the area, began a volume at 15:15 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 was reported inside it

Time	Report	Where	Remark
May 16, 10:20 AM CDT	Hail 0.75	Story City, IA
May 16, 10:30 AM CDT	Hail 0.75	Story City, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 16, 9:45 AM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 3.2 hours before the alert went out and 269 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: 266 J/kg
Mixed-layer CIN: -240 J/kg
Mixed-layer LCL: 780 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 114 m²/s²
0-3 km storm-relative helicity: 138 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at May 16, 3:45 AM CDT, 6 hours 27 minutes earlier.

Area forecast discussion, May 16, 3:45 AM CDT, 6 hours 27 minutes before

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In the hours before

Special weather statement, May 16, 6:20 AM CDT, 3 hours 52 minutes before

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Local storm report, May 16, 7:20 AM CDT, 2 hours 52 minutes before

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Local storm report, May 16, 9:00 AM CDT, 1 hour 12 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 3:52 AM CDT	Severe Thunderstorm Warning	DMX	Clarke	33 min
May 16, 4:09 AM CDT	Severe Thunderstorm Warning	DMX	Warren	36 min
May 16, 8:47 AM CDT	Severe Thunderstorm Warning	DMX	Greene	33 min
May 16, 9:19 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene	36 min
May 16, 9:24 AM CDT	Severe Thunderstorm Warning	DMX	Sac	41 min
May 16, 10:28 AM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Webster	32 min
May 16, 10:47 AM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Hardin	33 min
May 16, 10:58 AM CDT	Severe Thunderstorm Warning	DMX	Webster	32 min
May 16, 11:18 AM CDT	Severe Thunderstorm Warning	DMX	Hardin	32 min
May 16, 11:23 AM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Wright	47 min
May 16, 12:00 PM CDT	Severe Thunderstorm Warning	DMX	Franklin	45 min
May 16, 12:27 PM CDT	Severe Thunderstorm Warning	DMX	Butler	63 min
May 16, 12:40 PM CDT	Severe Thunderstorm Warning	DMX	Bremer	65 min
May 16, 12:46 PM CDT	Severe Thunderstorm Warning	DMX	Franklin	34 min
May 16, 1:28 PM CDT	Severe Thunderstorm Warning	DMX	Butler	32 min
May 16, 1:43 PM CDT	Severe Thunderstorm Warning	DMX	Bremer	62 min
May 16, 2:18 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	47 min
May 16, 3:42 PM CDT	Tornado Warning	DMX	Crawford	33 min
May 16, 4:13 PM CDT	Tornado Warning	DMX	Crawford	17 min
May 16, 4:20 PM CDT	Tornado Warning	DMX	Crawford	50 min
May 16, 4:33 PM CDT	Severe Thunderstorm Warning	DMX	Hardin	32 min
May 16, 4:38 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Grundy	32 min
May 16, 4:43 PM CDT	Tornado Warning	DMX	Sac	47 min
May 16, 5:55 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer	35 min
May 16, 6:13 PM CDT	Severe Thunderstorm Warning	DMX	Cass	32 min
May 16, 6:17 PM CDT	Flash Flood Warning	DMX	Hardin	2 hr
May 16, 6:26 PM CDT	Severe Thunderstorm Warning	DMX	Butler	34 min
May 16, 6:38 PM CDT	Tornado Warning	DMX	Audubon, Cass	47 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1999 Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.