Alert archive / Montana / Mesoscale Discussions in 2021
Mesoscale Discussion 911
The Storm Prediction Center issued this mesoscale discussion at Jun 10, 2021, 4:48 PM MDT for 8 counties in Montana. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- Jun 10, 2021, 4:48 PM MDT (22:48 UTC)
- Expired
- Jun 10, 2021, 6:15 PM MDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 252
Counties Garfield County, MT, Golden Valley County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Treasure County, MT, Valley County, MT, Yellowstone County, MT
The radar
The Glasgow radar (KGGW), 130 km from the middle of the area, began a volume at 22:48 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
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 10.8 hours before the alert went out and 132 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.
482
ACUS11 KWNS 102248
SWOMCD
SPC MCD 102248
MTZ000-110015-
Mesoscale Discussion 0911
NWS Storm Prediction Center Norman OK
0548 PM CDT Thu Jun 10 2021
Areas affected...Central into northeast MT
Concerning...Severe Thunderstorm Watch 252...
Valid 102248Z - 110015Z
The severe weather threat for Severe Thunderstorm Watch 252
continues.
SUMMARY...The threat for isolated severe hail and wind continues in
the short term, with a more organized wind threat possibly evolving
this evening.
DISCUSSION...At 2245Z, a cluster of strong to potentially severe
convection is ongoing across central MT, in advance of a strong
shortwave midlevel trough that is approaching the northern Rockies.
In the short term, strong multicell or occasional supercell
structures capable of isolated hail and strong wind gusts will be
the primary threat, supported by moderate MUCAPE and effective shear
of 35-45 kt.
A little later this evening, a more organized severe wind threat may
develop, as outflows consolidate and an accelerating cold front
moves into the region. As this occurs, one or more organized
clusters could move from central into northeast MT, potentially
capable of producing swaths of severe wind gusts, in addition to a
continued threat of isolated hail.
..Dean.. 06/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 46080950 47720889 48870790 48970718 48980622 47930594
46990589 46510625 45880771 45850911 46080950SPC 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, 1:56 PM MDT | Mesoscale Discussion | SPC | Daniels, Richland, Roosevelt, Sheridan, Valley, Wibaux | 94 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 |
Nearby
Mesoscale 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.