Alert archive / Montana / Mesoscale Discussions in 2020

Mesoscale Discussion 1413

August 6, 202028 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 6, 2020, 1:53 PM MDT for 28 counties in Montana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 6, 2020, 1:53 PM MDT (19:53 UTC)
Expired
Aug 6, 2020, 4:00 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%
All 28 counties

Beaverhead County, MT, Broadwater County, MT, Carbon County, MT, Cascade County, MT, Chouteau County, MT, Deer Lodge County, MT, Fergus County, MT, Gallatin County, MT, Golden Valley County, MT, Granite County, MT, Jefferson County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Madison County, MT, Meagher County, MT, Missoula County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Pondera County, MT, Powell County, MT, Ravalli County, MT, Silver Bow County, MT, Stillwater County, MT, Sweet Grass County, MT, Teton County, MT, Wheatland County, MT, Yellowstone County, MT

The radar

The Great Falls radar (KTFX), 93 km from the middle of the area, began a volume at 19:55 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 12:00Z, 7.9 hours before the alert went out and 90 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-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2020-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 59 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2020-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
59 J/kg
Mixed-layer CIN
-467 J/kg
Mixed-layer LCL
2592 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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Nearby

Mesoscale Discussions in Montana, 2020Every mesoscale discussion in 2020

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.