Alert archive / Iowa / Tornado Watches in 2010

Tornado Watch 57

April 6, 201036 counties in Iowa

The Storm Prediction Center issued this tornado watch at Apr 6, 2010, 2:57 PM CDT for 36 counties in Iowa. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 6, 2010, 2:57 PM CDT (19:57 UTC)
Expired
Apr 6, 2010, 9:32 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 36 counties

Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Clinton County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Dubuque County, IA, Grundy County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn 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, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 86 km from the middle of the area, began a volume at 19:57 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
50%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
90%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 6, 4:22 PM CDTSevere Thunderstorm WarningDVNBuchanan53 min
Apr 6, 4:35 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer, Grundy40 min
Apr 6, 5:03 PM CDTSevere Thunderstorm WarningDMXJasper, Lucas, Mahaska, Marion, Warren42 min
Apr 6, 5:11 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer34 min
Apr 6, 5:15 PM CDTSevere Thunderstorm WarningDVNBuchanan60 min
Apr 6, 5:44 PM CDTSevere Thunderstorm WarningDMXJasper, Mahaska, Poweshiek, Tama46 min
Apr 6, 5:57 PM CDTSevere Thunderstorm WarningDMXJasper, Poweshiek, Tama48 min
Apr 6, 6:01 PM CDTSevere Thunderstorm WarningDMXJasper, Marion26 min
Apr 6, 6:06 PM CDTSevere Thunderstorm WarningDMXWarren39 min
Apr 6, 6:07 PM CDTSevere Thunderstorm WarningDVNBuchanan, Delaware, Dubuque34 min
Apr 6, 6:08 PM CDTTornado WarningDMXPoweshiek, Tama37 min
Apr 6, 6:13 PM CDTSevere Thunderstorm WarningDMXClarke, Warren32 min
Apr 6, 6:18 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Linn57 min
Apr 6, 6:29 PM CDTSevere Thunderstorm WarningDMXJasper, Marion, Marshall, Polk, Poweshiek46 min
Apr 6, 6:57 PM CDTSevere Thunderstorm WarningDMXJasper, Poweshiek48 min
Apr 6, 6:59 PM CDTTornado WarningDVNBenton, Buchanan, Delaware, Linn43 min
Apr 6, 7:24 PM CDTTornado WarningDVNDelaware, Dubuque, Jones, Linn29 min
Apr 6, 7:33 PM CDTSevere Thunderstorm WarningDVNDelaware, Dubuque37 min
Apr 6, 7:41 PM CDTTornado WarningDMXJasper, Mahaska, Poweshiek34 min
Apr 6, 8:55 PM CDTSevere Thunderstorm WarningDVNJones, Linn35 min
Apr 6, 9:13 PM CDTSevere Thunderstorm WarningDVNCedar, Jones29 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

Davenport, (KDVN), launched 12:00Z, 8.0 hours before the alert went out and 193 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 2010-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 672 joules per kilogram.LCLLFCEL10008507005003002001001 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 2010-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 401 square meters per square second.1939587897Sfc1 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
672 J/kg
Mixed-layer CIN
-116 J/kg
Mixed-layer LCL
554 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
401 m²/s²
0-3 km storm-relative helicity
373 m²/s²
Significant tornado parameter
1.0
Supercell composite
19.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 5, 7:24 PM CDTMesoscale DiscussionSPCDecatur, Fremont, Page, Ringgold, Taylor66 min
Apr 5, 7:39 PM CDTTornado WatchSPCAdams, Appanoose, Clarke, Davis, Decatur, Lucas and 6 more3 hr
Apr 5, 9:37 PM CDTMesoscale DiscussionSPCBenton, Buchanan, Clayton, Delaware, Dubuque, Fayette and 3 more53 min
Apr 5, 9:54 PM CDTMesoscale DiscussionSPCAppanoose, Clarke, Decatur, Page, Ringgold, Taylor and 2 more66 min
Apr 5, 10:39 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 30 more6 hr
Apr 5, 11:07 PM CDTSevere Thunderstorm WatchSPCClinton, Jackson, Scott5 hr
Apr 6, 1:20 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Calhoun, Carroll and 34 more85 min
Apr 6, 4:05 AM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Bremer, Buchanan, Butler and 25 more85 min
Apr 6, 4:44 AM CDTSevere Thunderstorm WatchSPCClinton, Dubuque, Jackson, Scott4 hr
Apr 6, 1:32 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Clarke, Dallas, Decatur and 14 more58 min
Apr 6, 4:55 PM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Chickasaw and 8 more65 min
Apr 6, 5:06 PM CDTSevere Thunderstorm WatchSPCAllamakee, Clayton, Fayette, Winneshiek6 hr
Apr 6, 6:16 PM CDTMesoscale DiscussionSPCAppanoose, Benton, Cedar, Clarke, Davis, Decatur and 20 more59 min

Nearby

Tornado Watches in Iowa, 2010Every tornado watch in 2010

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.