Alert archive / Minnesota / Tornado Watches in 2015

Tornado Watch 178

May 16, 201518 counties in Minnesota; 4 counties in South Dakota

The Storm Prediction Center issued this tornado watch at May 16, 2015, 5:25 PM CDT for 18 counties in Minnesota; 4 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 16, 2015, 5:25 PM CDT (22:25 UTC)
Expired: May 16, 2015, 10:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 22 counties

Big Stone County, MN, Chippewa County, MN, Douglas County, MN, Grant County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, McLeod County, MN, Meeker County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Sherburne County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Wright County, MN, Yellow Medicine County, MN, Codington County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD

What SPC expected

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

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 16, 5:39 PM CDT	Tornado Warning Tornado observed	MPX	Swift	36 min
May 16, 5:45 PM CDT	Severe Thunderstorm Warning	MPX	Chippewa, Swift	17 min
May 16, 5:52 PM CDT	Tornado Warning Tornado observed	MPX	Chippewa, Swift	23 min
May 16, 6:11 PM CDT	Tornado Warning	MPX	Swift	34 min
May 16, 6:41 PM CDT	Tornado Warning	MPX	Pope, Swift	34 min
May 16, 7:03 PM CDT	Severe Thunderstorm Warning	MPX	Meeker, Renville	27 min
May 16, 7:15 PM CDT	Tornado Warning	MPX	McLeod, Meeker, Renville	30 min
May 16, 7:34 PM CDT	Tornado Warning	MPX	Chippewa, Swift	26 min
May 16, 7:35 PM CDT	Tornado Warning	MPX	Meeker	25 min
May 16, 7:40 PM CDT	Tornado Warning	MPX	Meeker	35 min
May 16, 7:44 PM CDT	Tornado Warning	MPX	Douglas, Pope	31 min
May 16, 8:25 PM CDT	Tornado Warning	MPX	Meeker, Stearns	35 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

Aberdeen, SD (KABR), launched 12:00Z, 10.4 hours before the alert went out and 195 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: 1 J/kg
Mixed-layer CIN: -146 J/kg
Mixed-layer LCL: 720 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 112 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.

683 
WWUS20 KWNS 162223
SEL8  
SPC WW 162223
MNZ000-SDZ000-170300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 178
NWS STORM PREDICTION CENTER NORMAN OK
525 PM CDT SAT MAY 16 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  WEST CENTRAL MINNESOTA
  EASTERN SOUTH DAKOTA

* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 525 PM UNTIL
  1000 PM CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...A CLUSTER OF STRONG TO SEVERE THUNDERSTORMS IS AFFECTING
PORTIONS OF WEST CENTRAL MN AND EASTERN SD...ALONG A SURFACE WARM
FRONT.  A FEW OF THESE STORMS HAVE SHOWN SUPERCELL STRUCTURES WITH A
THREAT OF HAIL AND A TORNADO OR TWO.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTH OF WATERTOWN
SOUTH DAKOTA TO 55 MILES EAST SOUTHEAST OF ALEXANDRIA 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 175...WW 176...WW 177...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23025.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 16, 2:10 PM CDT	Mesoscale Discussion	SPC	Big Stone, Brown, Chippewa, Cottonwood, Jackson, Kandiyohi and 13 more	95 min

Nearby

Tornado Watches in Minnesota, 2015 Tornado Watches in South 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.