Alert archive / Montana / Mesoscale Discussions in 2022
Mesoscale Discussion 1221
The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2022, 8:09 PM MDT for 6 counties in Montana. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 18, 2022, 8:09 PM MDT (02:09 UTC)
- Expired
- Jun 18, 2022, 10:15 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Blaine County, MT, Fergus County, MT, Golden Valley County, MT, Musselshell County, MT, Petroleum County, MT, Wheatland County, MT
The radar
The Great Falls radar (KTFX), 169 km from the middle of the area, began a volume at 02:13 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
Great_falls, MT (KTFX), launched 00:00Z, 2.2 hours before the alert went out and 110 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
- 341 J/kg
- Mixed-layer CIN
- -196 J/kg
- Mixed-layer LCL
- 1256 m above ground
- 0-6 km bulk shear
- 75 kt
- 0-1 km storm-relative helicity
- 153 m²/s²
- 0-3 km storm-relative helicity
- 473 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
209
ACUS11 KWNS 190209
SWOMCD
SPC MCD 190209
MTZ000-190415-
Mesoscale Discussion 1221
NWS Storm Prediction Center Norman OK
0909 PM CDT Sat Jun 18 2022
Areas affected...Parts of central Montana
Concerning...Severe potential...Watch unlikely
Valid 190209Z - 190415Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated large hail and perhaps strong wind gusts possible
with storms in central Montana for the next 2-4 hours.
DISCUSSION...Isolated, likely somewhat elevated, storm development
has occurred within the weak low-level/frontal convergence zone with
aid from the continued approach of a mid-level trough to from the
west. The 00Z observed TFX and GGW soundings sampled steep mid-level
lapse rates of around 8.5 C/km and relatively strong 0-6 km shear of
40-60 kts (stronger with westward extent). Though the GGW sounding
does have capping and boundary-layer cooling has begun, these storms
could still potentially produce isolated large hail and perhaps
strong wind gusts this evening given the upper-level support and
very modest moisture influx from the east. The 00Z HRRR seems to
capture this activity reasonably well and this activity may persist
for another 2-4 hours. These threats should remain isolated enough
that a watch is not likely this evening.
..Wendt/Guyer.. 06/19/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 47051015 48211011 48850954 49170914 49130843 47720767
46490818 45850849 45740914 45900961 47051015SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 19, 12:07 PM MDT | Mesoscale Discussion | SPC | Big Horn, Carter, Custer, Fallon, Powder River, Prairie and 3 more | 2 hr |
| Jun 19, 1:41 PM MDT | Severe Thunderstorm Watch | SPC | Big Horn, Carter, Custer, Dawson, Fallon, Powder River and 5 more | 6 hr |
| Jun 19, 4:52 PM MDT | Mesoscale Discussion | SPC | Carter | 83 min |
Nearby
Mesoscale Discussions in Montana, 2022Every mesoscale discussion in 2022
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.