Alert archive / North Dakota / Mesoscale Discussions in 2019

Mesoscale Discussion 1021

June 7, 2019Carter County, Fallon County, Montana; 4 counties in North Dakota; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 7, 2019, 5:28 PM MDT for Carter County, Fallon County, Montana; 4 counties in North Dakota; 4 counties in South Dakota. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Jun 7, 2019, 5:28 PM MDT (23:28 UTC)
Expired: Jun 7, 2019, 7:00 PM MDT
In force: 92 min
Issued by: the Storm Prediction Center

Counties Carter County, MT, Fallon County, MT, Adams County, ND, Bowman County, ND, Hettinger County, ND, Slope County, ND, Butte County, SD, Harding County, SD, Lawrence County, SD, Perkins County, SD

The radar

The Rapid City radar (KUDX), 192 km from the middle of the area, began a volume at 23:29 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 nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 11.5 hours before the alert went out and 196 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2420 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

334 
ACUS11 KWNS 072329
SWOMCD
SPC MCD 072328 
SDZ000-NDZ000-MTZ000-WYZ000-080100-

Mesoscale Discussion 1021
NWS Storm Prediction Center Norman OK
0628 PM CDT Fri Jun 07 2019

Areas affected...southeast MT...northwest SD...southwest ND

Concerning...Severe Thunderstorm Watch 340...

Valid 072328Z - 080100Z

The severe weather threat for Severe Thunderstorm Watch 340
continues.

SUMMARY...The severe risk is beginning to ramp up for areas over
northwest SD and southwest ND.  Severe gusts (60-75mph) and large
hail (1-2 inches in diameter) are the threats with the stronger
storms.

DISCUSSION...Water-vapor imagery shows a potent mid-level shortwave
trough moving through the Northern Rockies and northern
InterMountain regions early this evening.  Farther east over the
western Dakotas and southeast MT, the initial plume of 700-500mb
ascent will overspread this area during the next 1-2 hours according
to objective analyses.  

Surface analysis via observations and radar fine-line data indicate
a cold front is slowly pushing east across central ND with the
boundary stalling near the Black Hills.  Surface dewpoints in the
middle 50s are located over southwest ND into northwest SD.  It
appears most of the ongoing thunderstorm activity moving into the
western Dakotas is preferentially favoring the cool-side of the
boundary where shallow frontal lift is more supportive for storm
development compared to a capped warm sector farther east.  

Some short-term convection-allowing model guidance is suggestive
that the ongoing storms over southeast MT and the area along the
SD/WY border is the initial evolution of a severe-wind producing
cluster of thunderstorms expected to move northeast across southwest
ND/northwest SD and eventually into central ND later this evening. 
A new severe thunderstorm watch will likely be needed farther
northeast of severe thunderstorm watch 340.  However, during the
next 1-2 hours, the expectation is for a gradual intensification of
storms over southeast MT moving into the western Dakotas with the
risk for severe gusts coincidentally increasing.

..Smith.. 06/07/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ABR...BIS...UNR...BYZ...

LAT...LON   46590405 46710295 46360212 45910176 44180322 44220373
            45420525 45820539 46590405

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 7, 3:45 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Fallon, Powder River	6 hr
Jun 7, 2:54 PM MDT	Mesoscale Discussion	SPC	Butte, Custer, Fall River, Lawrence, Meade, Oglala Lakota and 1 more	3 hr

Nearby

Mesoscale Discussions in North Dakota, 2019 Mesoscale Discussions in South Dakota, 2019 Mesoscale Discussions in Montana, 2019 Every mesoscale discussion in 2019

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.