Alert archive / South Dakota / Winter Storm Warnings in 2011

Winter Storm Warning 2, NWS Rapid City, SD

January 21, 2011Lawrence County, Meade County, Pennington County, South Dakota; Crook County, Weston County, Wyoming

NWS Rapid City, SD issued this winter storm warning at Jan 21, 2011, 2:23 PM MST for Lawrence County, Meade County, Pennington County, South Dakota; Crook County, Weston County, Wyoming. It took effect at Jan 22, 2011, 2:00 AM MST. It was in force for 16 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jan 21, 2011, 2:23 PM MST (21:23 UTC)
In effect from: Jan 22, 2011, 2:00 AM MST
Expired: Jan 22, 2011, 6:26 PM MST
In force: 16 hr
Issued by: NWS Rapid City, SD

Counties Lawrence County, SD, Meade County, SD, Pennington County, SD, Crook County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 71 km from the middle of the area, began a volume at 21:26 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 12:00Z, 9.4 hours before the alert went out and 363 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: 480 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 379 m²/s²
0-3 km storm-relative helicity: 415 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 warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Rapid City, SD wrote its last area forecast discussion before this winter storm warning went out at Jan 21, 2:15 PM MST, 8 minutes earlier.

Area forecast discussion, Jan 21, 2:15 PM MST, 8 minutes before

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Hazardous weather outlook, Jan 21, 3:52 AM MST, 10 hours 31 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 21, 2:23 PM MST	Winter Weather Advisory	UNR	Butte, Custer, Harding, Lawrence, Meade, Pennington and 2 more	28 hr

Nearby

Winter Storm Warnings in South Dakota, 2011 Winter Storm Warnings in Wyoming, 2011 Every winter storm warning in 2011

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.