Alert archive / Montana / Mesoscale Discussions in 2017
Mesoscale Discussion 1018
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2017, 4:58 PM MDT for 12 counties in Montana. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2017, 4:58 PM MDT (22:58 UTC)
- Expired
- Jun 13, 2017, 7:00 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
Counties Blaine County, MT, Chouteau County, MT, Daniels County, MT, Dawson County, MT, Hill County, MT, Liberty County, MT, McCone County, MT, Phillips County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT
The radar
The Glasgow radar (KGGW), 98 km from the middle of the area, began a volume at 23:01 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, 11.0 hours before the alert went out and 100 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1083 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 317 m²/s²
- 0-3 km storm-relative helicity
- 302 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
122
ACUS11 KWNS 132259
SWOMCD
SPC MCD 132258
MTZ000-140100-
Mesoscale Discussion 1018
NWS Storm Prediction Center Norman OK
0558 PM CDT Tue Jun 13 2017
Areas affected...Portions of north-central and northeastern MT
Concerning...Severe potential...Watch unlikely
Valid 132258Z - 140100Z
Probability of Watch Issuance...5 percent
SUMMARY...An isolated and marginal risk for hail and strong/gusty
winds will exist through the evening hours. Watch issuance is not
expected.
DISCUSSION...22Z surface analysis indicates a 998 mb low in the
vicinity of Miles City MT. A narrow east-west corridor of limited
low-level moisture and surface heating across northeastern into
north-central MT has allowed weak to locally moderate instability to
develop. An upper low evident on water-vapor satellite imagery over
central MT will continue northeastward this evening, and strong
mid-level southerly to southeasterly winds, particularly across
northeastern MT, are supporting generally 30-40 kt of effective bulk
shear. Some isolated instances of marginally severe hail and
strong/gusty winds will be possible with any thunderstorm in this
environment for the next several hours. Already weak instability
should further lessen with the loss of daytime heating later this
evening. The overall severe threat will very likely remain too
isolated/marginal for watch issuance.
..Gleason/Edwards.. 06/13/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GGW...TFX...
LAT...LON 47531074 47661131 49051093 49040745 49040408 47670413
46990464 47490644 47980742 47910905 47531074SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 12, 6:00 PM MDT | Mesoscale Discussion | SPC | Big Horn, Carbon, Golden Valley, Musselshell, Park, Stillwater and 4 more | 90 min |
Nearby
Mesoscale Discussions in Montana, 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.