Alert archive / Montana / Mesoscale Discussions in 2020

Mesoscale Discussion 770

May 30, 20209 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at May 30, 2020, 5:00 PM MDT for 9 counties in Montana. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
May 30, 2020, 5:00 PM MDT (23:00 UTC)
Expired
May 30, 2020, 6:30 PM MDT
In force
90 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Broadwater County, MT, Cascade County, MT, Granite County, MT, Jefferson County, MT, Lewis and Clark County, MT, Meagher County, MT, Missoula County, MT, Powell County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 83 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

Spokane, WA (KOTX), launched 12:00Z, 11.0 hours before the alert went out and 316 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, Spokane, WA at 12:00Z on 2020-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Spokane, WA at 12:00Z on 2020-05-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 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
4 J/kg
Mixed-layer CIN
-470 J/kg
Mixed-layer LCL
2315 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
133 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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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 30, 1:45 PM MDTMesoscale DiscussionSPCCarbon, Gallatin, Madison, Park90 min

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.