Alert archive / South Dakota / Flash Flood Watches in 2007

Flash Flood Watch 1, NWS Aberdeen, SD

April 21, 200722 counties in South Dakota; Big Stone County, Traverse County, Minnesota

NWS Aberdeen, SD issued this flash flood watch at Apr 21, 2007, 3:41 AM CDT for 22 counties in South Dakota; Big Stone County, Traverse County, Minnesota. It took effect at Apr 21, 2007, 1:00 PM CDT. It was in force for 15 hr.

The area

The counties it named.

The facts

Issued: Apr 21, 2007, 3:41 AM CDT (08:41 UTC)
In effect from: Apr 21, 2007, 1:00 PM CDT
Expired: Apr 22, 2007, 3:54 AM CDT
In force: 15 hr
Issued by: NWS Aberdeen, SD
Flood severity: None

All 24 counties

Big Stone County, MN, Traverse County, MN, Brown County, SD, Buffalo County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Hamlin County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Stanley County, SD, Sully County, SD

The radar

The Aberdeen radar (KABR), 57 km from the middle of the area, began a volume at 08:41 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

Bismarck Municip, ND (KBIS), launched 00:00Z, 8.7 hours before the alert went out and 265 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2720 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 243 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Aberdeen, SD wrote its last area forecast discussion before this flash flood watch went out at Apr 21, 3:24 AM CDT, 17 minutes earlier.

Area forecast discussion, Apr 21, 3:24 AM CDT, 17 minutes before

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In the hours before

Local storm report, Apr 20, 10:11 PM CDT, 5 hours 30 minutes before

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The office that day

Everything else NWS Aberdeen, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 20, 7:17 PM CDT	Severe Thunderstorm Warning	ABR	Faulk	28 min
Apr 20, 7:47 PM CDT	Severe Thunderstorm Warning	ABR	Faulk	28 min
Apr 20, 8:01 PM CDT	Severe Thunderstorm Warning	ABR	Hand	29 min
Apr 20, 8:17 PM CDT	Severe Thunderstorm Warning	ABR	Brown, Faulk, Spink	43 min
Apr 20, 8:32 PM CDT	Severe Thunderstorm Warning	ABR	Hand	28 min
Apr 20, 9:02 PM CDT	Severe Thunderstorm Warning	ABR	Brown	28 min

Nearby

Flash Flood Watches in South Dakota, 2007 Flash Flood Watches in Minnesota, 2007 Every flash flood watch in 2007

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.