Alert archive / Minnesota / Tornado Watches in 2017

Tornado Watch 232

May 17, 201722 counties in Minnesota

The Storm Prediction Center issued this tornado watch at May 17, 2017, 2:53 PM CDT for 22 counties in Minnesota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 17, 2017, 2:53 PM CDT (19:53 UTC)
Expired
May 17, 2017, 8:40 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 22 counties

Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dakota County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Pipestone County, MN, Redwood County, MN, Rice County, MN, Rock County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN

The radar

The Minneapolis radar (KMPX), 127 km from the middle of the area, began a volume at 19:56 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
30%
One or more EF2 to EF5 tornadoes
10%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 17, 2:56 PM CDTSevere Thunderstorm WarningMPXFreeborn34 min
May 17, 3:08 PM CDTSevere Thunderstorm WarningMPXFreeborn, Steele24 min
May 17, 3:10 PM CDTSevere Thunderstorm WarningMPXBlue Earth, Faribault35 min
May 17, 3:30 PM CDTSevere Thunderstorm WarningMPXSteele30 min
May 17, 3:42 PM CDTTornado WarningMPXBlue Earth33 min
May 17, 3:55 PM CDTTornado WarningMPXSteele21 min
May 17, 4:00 PM CDTSevere Thunderstorm WarningMPXRice, Steele30 min
May 17, 4:03 PM CDTSevere Thunderstorm WarningMPXBlue Earth, Brown, Nicollet27 min
May 17, 4:11 PM CDTTornado WarningMPXBlue Earth, Nicollet19 min
May 17, 5:01 PM CDTFlash Flood WarningMPXBlue Earth, Le Sueur, Nicollet119 min
May 17, 7:39 PM CDTSevere Thunderstorm WarningMPXGoodhue49 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

Minneapolis, MN (KMPX), launched 12:00Z, 7.9 hours before the alert went out and 125 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2017-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2017-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
737 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
-70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

550 
WWUS20 KWNS 171951
SEL2  
SPC WW 171951
MNZ000-180300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 232
NWS Storm Prediction Center Norman OK
255 PM CDT Wed May 17 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  southern Minnesota

* Effective this Wednesday afternoon and evening from 255 PM
  until 1000 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 70 mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Strong/locally severe storms continue spreading northward
out of IA into southern MN this afternoon, as the airmass continues
to destabilize.  Large hail and locally damaging winds will be
possible, along with the potential for a couple of tornadoes with
the strongest cells.

The tornado watch area is approximately along and 35 statute miles
north and south of a line from 65 miles west southwest of Redwood
Falls MN to 45 miles east of Mankato MN. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU2).

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 231...

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 450. Mean
storm motion vector 18035.

...Goss

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 16, 8:46 PM CDTSevere Thunderstorm WatchSPCDodge, Fillmore, Freeborn, Houston, Mower, Olmsted and 2 more5 hr
May 16, 9:14 PM CDTMesoscale DiscussionSPCWabasha61 min
May 16, 11:48 PM CDTMesoscale DiscussionSPCDodge, Fillmore, Houston, Mower, Olmsted, Steele and 2 more117 min
May 17, 12:23 PM CDTMesoscale DiscussionSPCHouston, Winona97 min
May 17, 2:38 PM CDTMesoscale DiscussionSPCDakota, Dodge, Fillmore, Freeborn, Goodhue, Houston and 7 more97 min
May 17, 3:13 PM CDTTornado WatchSPCDodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more9 hr
May 17, 6:05 PM CDTMesoscale DiscussionSPCFillmore, Houston, Mower55 min

Nearby

Tornado Watches in Minnesota, 2017Every tornado watch in 2017

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.