Alert archive / Minnesota / Tornado Watches in 2015

Tornado Watch 498

August 22, 201526 counties in Minnesota; 6 counties in North Dakota

The Storm Prediction Center issued this tornado watch at Aug 22, 2015, 2:56 PM CDT for 26 counties in Minnesota; 6 counties in North Dakota. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: Aug 22, 2015, 2:56 PM CDT (19:56 UTC)
Expired: Aug 22, 2015, 10:39 PM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 32 counties

Aitkin County, MN, Becker County, MN, Beltrami County, MN, Carlton County, MN, Cass County, MN, Clay County, MN, Clearwater County, MN, Crow Wing County, MN, Grant County, MN, Hubbard County, MN, Itasca County, MN, Kittson County, MN, Koochiching County, MN, Lake of the Woods County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Otter Tail County, MN, Pennington County, MN, Pine County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN, Saint Louis County, MN, Wadena County, MN, Wilkin County, MN, Cass County, ND, Grand Forks County, ND, Pembina County, ND, Richland County, ND, Traill County, ND, Walsh County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 157 km from the middle of the area, began a volume at 19:58 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 80%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 50%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Aug 22, 6:20 PM CDT	Severe Thunderstorm Warning	DLH	Cass, Crow Wing	25 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 7.9 hours before the alert went out and 167 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: 246 J/kg
Mixed-layer CIN: -335 J/kg
Mixed-layer LCL: 1267 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

188 
WWUS20 KWNS 221952
SEL8  
SPC WW 221952
MNZ000-NDZ000-WIZ000-230500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 498
NWS STORM PREDICTION CENTER NORMAN OK
250 PM CDT SAT AUG 22 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  NORTHERN MINNESOTA
  FAR EASTERN NORTH DAKOTA
  FAR NORTHWEST WISCONSIN

* EFFECTIVE THIS SATURDAY AFTERNOON FROM 250 PM UNTIL MIDNIGHT
  CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  WIDESPREAD DAMAGING WIND GUSTS TO 70 MPH LIKELY
  SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE

SUMMARY...THUNDERSTORMS...INCLUDING POSSIBLE SUPERCELLS AND OTHER
LONG-LIVED STORMS...EXPECTED TO FORM OVER FAR EASTERN ND AND
POSSIBLY OVER NW/N CENTRAL MN OVER THE NEXT FEW HOURS. THE STORMS
WILL MOVE/DEVELOP NORTHEAST OR NORTH-NORTHEASTWARD THROUGH LATE
EVENING...WITH SOME BECOMING CAPABLE OF TORNADOES...IN ADDITION TO
DAMAGING WIND AND MARGINALLY SEVERE HAIL.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 115 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES EAST NORTHEAST OF
WARROAD MINNESOTA TO 20 MILES SOUTHWEST OF BRAINERD MINNESOTA. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 497...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 21040.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 22, 2:13 PM CDT	Mesoscale Discussion	SPC	Anoka, Benton, Big Stone, Blue Earth, Brown, Carver and 42 more	62 min
Aug 22, 2:35 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Beltrami, Cass, Clay, Clearwater and 18 more	55 min
Aug 22, 2:35 PM CDT	Tornado Watch	SPC	Anoka, Benton, Big Stone, Blue Earth, Brown, Carver and 46 more	7 hr
Aug 22, 5:42 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Beltrami, Carlton, Cass, Clearwater and 16 more	93 min
Aug 22, 5:52 PM CDT	Mesoscale Discussion	SPC	Anoka, Benton, Blue Earth, Brown, Carver, Chisago and 24 more	83 min
Aug 22, 6:12 PM CDT	Mesoscale Discussion	SPC	Dodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more	63 min

Nearby

Tornado Watches in Minnesota, 2015 Tornado Watches in North Dakota, 2015 Every tornado watch in 2015

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.