Alert archive / Washington / Mesoscale Discussions in 2020

Mesoscale Discussion 771

May 30, 20209 counties in Idaho; Mineral County, Sanders County, Montana; 15 counties in Washington

The Storm Prediction Center issued this mesoscale discussion at May 30, 2020, 8:06 PM PDT for 9 counties in Idaho; Mineral County, Sanders County, Montana; 15 counties in Washington. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: May 30, 2020, 8:06 PM PDT (03:06 UTC)
Expired: May 30, 2020, 10:00 PM PDT
In force: 114 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 237

All 26 counties

Benewah County, ID, Bonner County, ID, Boundary County, ID, Clearwater County, ID, Kootenai County, ID, Latah County, ID, Lewis County, ID, Nez Perce County, ID, Shoshone County, ID, Mineral County, MT, Sanders County, MT, Adams County, WA, Asotin County, WA, Benton County, WA, Columbia County, WA, Douglas County, WA, Ferry County, WA, Franklin County, WA, Garfield County, WA, Grant County, WA, Lincoln County, WA, Pend Oreille County, WA, Spokane County, WA, Stevens County, WA, Walla Walla County, WA, Whitman County, WA

The radar

The Spokane radar (KOTX), 75 km from the middle of the area, began a volume at 03:05 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 00:00Z, 3.1 hours before the alert went out and 128 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 124 J/kg
Mixed-layer CIN: -408 J/kg
Mixed-layer LCL: 2380 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 303 m²/s²
0-3 km storm-relative helicity: 350 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.

Issued	Product	Office	Counties	Lasted
May 31, 1:38 AM PDT	Mesoscale Discussion	SPC	Ada, Adams, Boise, Canyon, Gem, Idaho and 5 more	2 hr
May 31, 1:29 PM PDT	Mesoscale Discussion	SPC	Blaine, Daniels, Phillips, Valley	2 hr
May 31, 1:35 PM PDT	Mesoscale Discussion	SPC	Big Horn, Carter, Custer, Dawson, Fallon, Powder River and 4 more	115 min
May 31, 3:07 PM PDT	Severe Thunderstorm Watch	SPC	Carter, Custer, Dawson, Fallon, Powder River, Prairie and 1 more	6 hr

Nearby

Mesoscale Discussions in Washington, 2020 Mesoscale Discussions in Idaho, 2020 Mesoscale Discussions in Montana, 2020 Every 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.