Alert archive / Washington / Mesoscale Discussions in 2013

Mesoscale Discussion 1845

September 5, 201310 counties in Idaho; 13 counties in Montana; 16 counties in Washington

The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2013, 9:44 PM PDT for 10 counties in Idaho; 13 counties in Montana; 16 counties in Washington. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 5, 2013, 9:44 PM PDT (04:44 UTC)
Expired: Sep 5, 2013, 11:45 PM PDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 39 counties

Benewah County, ID, Bonner County, ID, Clearwater County, ID, Idaho County, ID, Kootenai County, ID, Latah County, ID, Lemhi County, ID, Lewis County, ID, Nez Perce County, ID, Shoshone County, ID, Beaverhead County, MT, Broadwater County, MT, Deer Lodge County, MT, Granite County, MT, Jefferson County, MT, Lake County, MT, Madison County, MT, Mineral County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Sanders County, MT, Silver Bow 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, Okanogan 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), 155 km from the middle of the area, began a volume at 04:47 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, 4.7 hours before the alert went out and 137 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: 837 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 1076 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: -1 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 5, 5:28 PM PDT	Mesoscale Discussion	SPC	Benewah, Bonner, Boundary, Kootenai, Latah, Shoshone	2 hr
Sep 5, 5:34 PM PDT	Mesoscale Discussion	SPC	Bannock, Bingham, Blaine, Butte, Cassia, Clark and 9 more	116 min
Sep 5, 6:05 PM PDT	Severe Thunderstorm Watch	SPC	Benewah, Bonner, Boundary, Kootenai, Latah, Shoshone	7 hr
Sep 5, 7:13 PM PDT	Mesoscale Discussion	SPC	Adams, Benewah, Bonner, Clearwater, Idaho, Kootenai and 5 more	2 hr
Sep 6, 12:44 PM PDT	Mesoscale Discussion	SPC	Broadwater, Cascade, Chouteau, Gallatin, Hill, Jefferson and 11 more	61 min
Sep 6, 1:09 PM PDT	Severe Thunderstorm Watch	SPC	Blaine, Broadwater, Cascade, Chouteau, Deer Lodge, Fergus and 18 more	8 hr
Sep 6, 4:04 PM PDT	Mesoscale Discussion	SPC	Blaine, Cascade, Chouteau, Fergus, Golden Valley, Hill and 9 more	86 min

Nearby

Mesoscale Discussions in Washington, 2013 Mesoscale Discussions in Montana, 2013 Mesoscale Discussions in Idaho, 2013 Every mesoscale discussion in 2013

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.