Alert archive / North Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 908
The Storm Prediction Center issued this mesoscale discussion at Jun 10, 2021, 1:56 PM MDT for 6 counties in Montana; 13 counties in North Dakota. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Jun 10, 2021, 1:56 PM MDT (19:56 UTC)
- Expired
- Jun 10, 2021, 3:30 PM MDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...tornado watch likely
- Chance of a watch
- 95%
Counties Daniels County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Burke County, ND, Divide County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Mountrail County, ND, Slope County, ND, Stark County, ND, Williams County, ND
The radar
The Glasgow radar (KGGW), 126 km from the middle of the area, began a volume at 19:59 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
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 7.9 hours before the alert went out and 124 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.
- Mixed-layer CAPE
- 929 J/kg
- Mixed-layer CIN
- -480 J/kg
- Mixed-layer LCL
- 774 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 651 m²/s²
- 0-3 km storm-relative helicity
- 663 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
492
ACUS11 KWNS 101957
SWOMCD
SPC MCD 101956
NDZ000-SDZ000-MTZ000-102130-
Mesoscale Discussion 0908
NWS Storm Prediction Center Norman OK
0256 PM CDT Thu Jun 10 2021
Areas affected...far northeast MT...western ND
Concerning...Severe potential...Tornado Watch likely
Valid 101956Z - 102130Z
Probability of Watch Issuance...95 percent
SUMMARY...Convective initiation is expected between 20-21 UTC along
the dryline over eastern MN near the ND border. Explosive growth
into significant-severe producing supercells is forecast late this
afternoon into the early evening.
DISCUSSION...Visible-satellite imagery shows a swelling band of
agitated cumulus along the dryline over far eastern MT near Sydney.
Temperatures immediately east of the dryline have warmed into the
lower 80s with a deepening boundary layer featuring low to mid 60s
deg F dewpoints. The 18 UTC Glasgow, MT raob showed a very steep
700-500 mb lapse rate (8.6 deg C/km). Modifying the raob for 19 UTC
surface conditions east of the dryline near the ND/MT border (i.e.,
Sydney, MT) yielded 3300 J/kg MLCAPE with very little convective
inhibition remaining. As the cap erodes, expecting explosive
updraft growth quickly evolving into a few discrete supercells.
Giant hail (3+ inches in diameter) is possible with the stronger
storms as the organize and move northeast into a less deeply mixed
and more moisture rich environment near the warm front. Supercell
tornadoes will be possible in vicinity of the warm front, in
addition to the hail/severe gust hazard. Other isolated storms are
forecast to eventually develop southward along the dryline into
parts of southwest ND and northwest SD. Large to giant hail will be
the primary hazard with these storms before additional thunderstorm
development into a severe squall line evolves later this evening.
..Smith/Guyer.. 06/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BIS...UNR...BYZ...GGW...
LAT...LON 48980713 48560749 48100717 48090558 47640477 45790370
45970205 48380212 48970265 48980713SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 9, 6:42 PM MDT | Severe Thunderstorm Watch | SPC | Blaine, Chouteau, Fergus, Hill, Judith Basin, Petroleum and 1 more | 5 hr |
| Jun 9, 8:34 PM MDT | Mesoscale Discussion | SPC | Blaine, Chouteau, Fergus, Hill, Judith Basin, Petroleum and 1 more | 86 min |
| Jun 9, 10:51 PM MDT | Mesoscale Discussion | SPC | Blaine, Fergus, Petroleum, Phillips | 84 min |
| Jun 10, 1:47 PM MDT | Mesoscale Discussion | SPC | Blaine, Fergus, Golden Valley, Musselshell, Petroleum, Phillips and 4 more | 88 min |
| Jun 10, 2:30 PM MDT | Tornado Watch | SPC | Daniels, Richland, Roosevelt, Sheridan, Wibaux | 6 hr |
| Jun 10, 2:51 PM MDT | Mesoscale Discussion | SPC | Carter | 114 min |
| Jun 10, 2:52 PM MDT | Severe Thunderstorm Watch | SPC | Blaine, Custer, Dawson, Fergus, Garfield, Golden Valley and 7 more | 6 hr |
| Jun 10, 4:36 PM MDT | Mesoscale Discussion | SPC | Fallon, Richland, Roosevelt, Sheridan, Wibaux | 114 min |
| Jun 10, 4:48 PM MDT | Mesoscale Discussion | SPC | Garfield, Golden Valley, Musselshell, Petroleum, Phillips, Treasure and 2 more | 87 min |
Nearby
Mesoscale Discussions in North Dakota, 2021Mesoscale Discussions in Montana, 2021Every mesoscale discussion in 2021
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.