Alert archive / South Dakota / Winter Storm Watches in 2007

Winter Storm Watch 7, NWS Sioux Falls, SD

December 7, 20076 counties in South Dakota; Plymouth County, Woodbury County, Iowa

NWS Sioux Falls, SD issued this winter storm watch at Dec 7, 2007, 4:02 AM CST for 6 counties in South Dakota; Plymouth County, Woodbury County, Iowa. It took effect at Dec 8, 2007, 6:00 AM CST. It was in force for .

The area

The counties it named.

The facts

Issued: Dec 7, 2007, 4:02 AM CST (10:02 UTC)
In effect from: Dec 8, 2007, 6:00 AM CST
Expired: Dec 7, 2007, 3:23 PM CST
In force
Issued by: NWS Sioux Falls, SD

Counties Plymouth County, IA, Woodbury County, IA, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Gregory County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 92 km from the middle of the area, began a volume at 10:06 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 10.0 hours before the alert went out and 332 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: 653 m above ground
0-6 km bulk shear: 81 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 77 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 winter storm watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before this winter storm watch went out at Dec 7, 3:42 AM CST, 20 minutes earlier.

Area forecast discussion, Dec 7, 3:42 AM CST, 20 minutes before

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Hazardous weather outlook, Dec 6, 10:13 AM CST, 17 hours 49 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 7, 3:23 PM CST	Heavy Snow Warning	FSD	Clay, Union, Yankton	22 hr
Dec 7, 3:23 PM CST	Snow Advisory	FSD	Aurora, Bon Homme, Charles Mix, Clay, Davison, Douglas and 9 more	37 hr

Nearby

Winter Storm Watches in South Dakota, 2007 Winter Storm Watches in Iowa, 2007 Every winter storm 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.