Alert archive / Montana / Mesoscale Discussions in 2017

Mesoscale Discussion 994

June 12, 20176 counties in Idaho; 9 counties in Montana; Park County, Teton County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2017, 11:23 AM MDT for 6 counties in Idaho; 9 counties in Montana; Park County, Teton County, Wyoming. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jun 12, 2017, 11:23 AM MDT (17:23 UTC)
Expired
Jun 12, 2017, 2:00 PM MDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%

Counties Bonneville County, ID, Clark County, ID, Fremont County, ID, Jefferson County, ID, Madison County, ID, Teton County, ID, Beaverhead County, MT, Carbon County, MT, Gallatin County, MT, Jefferson County, MT, Madison County, MT, Park County, MT, Silver Bow County, MT, Stillwater County, MT, Sweet Grass County, MT, Park County, WY, Teton County, WY

The radar

The Pocatello radar (KSFX), 214 km from the middle of the area, began a volume at 17:23 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 5.4 hours before the alert went out and 287 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, Riverton, WY at 12:00Z on 2017-06-12Temperature 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 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2017-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 89 square meters per square second.19395878Sfc1 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
956 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
89 m²/s²
0-3 km storm-relative helicity
173 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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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 12, 2:17 PM MDTMesoscale DiscussionSPCBig Horn, Carbon, Gallatin, Park, Stillwater, Sweet Grass88 min
Jun 12, 2:45 PM MDTSevere Thunderstorm WatchSPCBig Horn, Carbon, Golden Valley, Musselshell, Park, Powder River and 6 more7 hr
Jun 12, 11:29 AM MDTMesoscale DiscussionSPCConverse, Goshen, Laramie, Niobrara, Platte, Weston2 hr
Jun 12, 1:11 PM MDTTornado Watch PDSSPCAlbany, Converse, Goshen, Laramie, Niobrara, Platte8 hr
Jun 12, 5:05 PM MDTMesoscale DiscussionSPCConverse, Goshen, Laramie, Niobrara, Platte, Weston85 min
Jun 12, 5:35 PM MDTTornado WatchSPCCampbell, Crook, Weston8 hr

Nearby

Mesoscale Discussions in Montana, 2017Mesoscale Discussions in Idaho, 2017Mesoscale Discussions in Wyoming, 2017Every mesoscale discussion 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.