Alert archive / North Dakota / Tornado Warnings in 2011

Tornado Warning 71, NWS Bismarck, ND

July 18, 2011Sioux County, North Dakota

NWS Bismarck, ND issued this tornado warning at Jul 18, 2011, 8:30 PM CDT for Sioux County, North Dakota. It was in force for 30 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 18, 2011, 8:30 PM CDT (01:30 UTC)
Expired: Jul 18, 2011, 9:00 PM CDT
In force: 30 min
Issued by: NWS Bismarck, ND
Area: Storm-based polygon

County Sioux County, ND

The radar

The Bismarck radar (KBIS), 116 km from the middle of the area, began a volume at 01:30 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 was reported inside it

Time	Report	Where	Remark
Jul 18, 8:30 PM CDT	HAIL 1	50 W Selfridge, ND	HAIL LASTED A FEW MINUTES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 18, 3:28 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 00:00Z, 1.5 hours before the alert went out and 119 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: 3044 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 1324 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 3.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

461 
WFUS53 KBIS 190130
TORBIS
NDC085-190200-
/O.NEW.KBIS.TO.W.0071.110719T0130Z-110719T0200Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE BISMARCK ND
730 PM MDT MON JUL 18 2011

THE NATIONAL WEATHER SERVICE IN BISMARCK HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHWESTERN SIOUX COUNTY IN SOUTH CENTRAL NORTH DAKOTA...

* UNTIL 800 PM MDT

* AT 726 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED NEAR THUNDER HAWK...OR 11 MILES EAST OF LEMMON...
  AND MOVING EAST AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF SOUTHWESTERN SIOUX COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

THIS IS A SUPERCELL THUNDERSTORM. IN ADDITION TO 
TORNADOES...SUPERCELLS ARE CAPABLE OF PRODUCING EXTREMELY LARGE HAIL 
UP TO GOLF BALL SIZE. ACT QUICKLY AND MOVE TO SAFETY INSIDE A STURDY 
SHELTER...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM ON THE LOWEST 
FLOOR.

&&

LAT...LON 4605 10200 4607 10185 4603 10183 4604 10182
      4602 10180 4604 10179 4604 10174 4601 10167
      4604 10163 4594 10163 4593 10200
TIME...MOT...LOC 0129Z 269DEG 11KT 4597 10192

$$

HEINERT

2 follow-up statements

883 
WWUS53 KBIS 190149
SVSBIS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BISMARCK ND
849 PM CDT MON JUL 18 2011

NDC085-190200-
/O.CON.KBIS.TO.W.0071.000000T0000Z-110719T0200Z/
SIOUX ND-
749 PM MDT MON JUL 18 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHWESTERN SIOUX COUNTY
UNTIL 800 PM MDT...

AT 748 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR KELDRON...OR 15 MILES EAST OF LEMMON...MOVING
EAST AT 15 MPH.

LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF SOUTHWESTERN SIOUX COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4602 10178 4600 10167 4600 10165 4594 10163
      4594 10193 4600 10195 4602 10186 4602 10182
TIME...MOT...LOC 0149Z 269DEG 11KT 4597 10184

$$

HEINERT

786 
WWUS53 KBIS 190202
SVSBIS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BISMARCK ND
902 PM CDT MON JUL 18 2011

NDC085-190211-
/O.EXP.KBIS.TO.W.0071.000000T0000Z-110719T0200Z/
SIOUX ND-
802 PM MDT MON JUL 18 2011

...THE TORNADO WARNING FOR SOUTHWESTERN SIOUX COUNTY HAS EXPIRED...

THE STRONG ROTATION WITH THIS STORM HAS WEAKENED CONSIDERABLY. 
HOWEVER...THIS STORM MAY STILL INTENSIFY. 

A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN GRANT 
AND SOUTHWESTERN SIOUX COUNTIES UNTIL 845 PM MDT.

LAT...LON 4602 10178 4600 10167 4600 10165 4594 10163
      4594 10193 4600 10195 4602 10186 4602 10182
TIME...MOT...LOC 0149Z 269DEG 11KT 4597 10184

$$

HEINERT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 7:22 PM CDT	Tornado Warning	BIS	Adams	38 min
Jul 18, 7:43 PM CDT	Severe Thunderstorm Warning	BIS	Adams, Grant, Sioux	62 min
Jul 18, 8:01 PM CDT	Tornado Warning	BIS	Adams, Grant, Sioux	29 min
Jul 18, 8:46 PM CDT	Severe Thunderstorm Warning	BIS	Grant, Sioux	45 min
Jul 18, 9:19 PM CDT	Areal Flood Advisory	BIS	Sioux	9 hr
Jul 19, 2:57 PM CDT	Wind Advisory	BIS	Adams, Billings, Bowman, Burke, Burleigh, Divide and 13 more	28 hr
Jul 19, 4:55 PM CDT	Severe Thunderstorm Warning	BIS	Golden Valley	65 min
Jul 19, 5:39 PM CDT	Severe Thunderstorm Warning	BIS	Billings, Golden Valley, Slope	66 min
Jul 19, 6:44 PM CDT	Severe Thunderstorm Warning	BIS	Billings, Golden Valley, Slope	61 min
Jul 19, 6:54 PM CDT	Flash Flood Warning	BIS	Billings, Golden Valley, Slope	4 hr

Nearby

Tornado Warnings in North Dakota, 2011 Every tornado warning in 2011 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.