Alert archive / North Dakota / Special Weather Statements in 2021

Special Weather Statement, NWS Bismarck, ND

August 23, 2021Sioux County, North Dakota

NWS Bismarck, ND issued this special weather statement at Aug 23, 2021, 9:53 PM CDT for Sioux County, North Dakota. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 23, 2021, 9:53 PM CDT (02:53 UTC)
Expired: Aug 23, 2021, 10:30 PM CDT
In force: 37 min
Issued by: NWS Bismarck, ND
Hail: 0.88 in
Wind: 40

County Sioux County, ND

The radar

The Bismarck radar (KBIS), 83 km from the middle of the area, began a volume at 02:52 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, 2.9 hours before the alert went out and 83 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: 16 J/kg
Mixed-layer CIN: -172 J/kg
Mixed-layer LCL: 2391 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 180 m²/s²
0-3 km storm-relative helicity: 508 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

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

NWS Bismarck, ND wrote its last area forecast discussion before this special weather statement went out at Aug 23, 7:16 PM CDT, 2 hours 37 minutes earlier.

Area forecast discussion, Aug 23, 7:16 PM CDT, 2 hours 37 minutes before

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Hazardous weather outlook, Aug 23, 7:30 PM CDT, 2 hours 23 minutes before

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In the hours before

Special weather statement, Aug 23, 9:53 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service Bismarck ND
953 PM CDT Mon Aug 23 2021

NDZ045-240330-
Sioux ND-
953 PM CDT Mon Aug 23 2021

...A strong thunderstorm will impact portions of southeastern Sioux
County through 1030 PM CDT...

At 953 PM CDT, Doppler radar was tracking a strong thunderstorm over
Selfridge, moving northeast at 40 mph.

HAZARD...Winds in excess of 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Fort Yates.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4604 10110 4623 10070 4612 10061 4606 10061
      4601 10056 4599 10052 4597 10051 4595 10051
      4594 10052 4594 10102
TIME...MOT...LOC 0253Z 238DEG 33KT 4600 10094

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

TELKEN

The office that day

Everything else NWS Bismarck, ND issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 23, 10:06 PM CDT	Severe Thunderstorm Warning	BIS	Sioux	24 min
Aug 23, 11:38 PM CDT	Special Weather Statement	BIS	Logan, McIntosh	37 min
Aug 24, 12:01 AM CDT	Special Weather Statement	BIS	Grant	29 min
Aug 24, 12:14 AM CDT	Severe Thunderstorm Warning	BIS	Grant, Morton	46 min
Aug 24, 12:23 AM CDT	Special Weather Statement	BIS	Dickey, LaMoure	37 min
Aug 24, 12:45 AM CDT	Severe Thunderstorm Warning Considerable damage threat	BIS	Dickey	30 min
Aug 24, 1:03 AM CDT	Special Weather Statement	BIS	Emmons	27 min
Aug 24, 2:01 AM CDT	Special Weather Statement	BIS	Logan	29 min
Aug 24, 2:57 AM CDT	Areal Flood Advisory	BIS	Logan	98 min
Aug 24, 5:54 AM CDT	Special Weather Statement	BIS	Mountrail	36 min
Aug 24, 6:16 AM CDT	Severe Thunderstorm Warning	BIS	McLean, Mountrail, Ward	29 min
Aug 24, 7:26 AM CDT	Special Weather Statement	BIS	Pierce	34 min
Aug 24, 8:19 AM CDT	Special Weather Statement	BIS	McHenry	26 min

Nearby

Special Weather Statements in North Dakota, 2021 Every special weather statement in 2021

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.