Alert archive / Oregon / Mesoscale Discussions in 2014

Mesoscale Discussion 1550

August 12, 2014Nez Perce County, Idaho; 10 counties in Oregon; 7 counties in Washington

The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2014, 12:57 PM PDT for Nez Perce County, Idaho; 10 counties in Oregon; 7 counties in Washington. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Aug 12, 2014, 12:57 PM PDT (19:57 UTC)
Expired: Aug 12, 2014, 2:30 PM PDT
In force: 93 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Nez Perce County, ID, Gilliam County, OR, Hood River County, OR, Jefferson County, OR, Morrow County, OR, Sherman County, OR, Umatilla County, OR, Union County, OR, Wallowa County, OR, Wasco County, OR, Wheeler County, OR, Asotin County, WA, Benton County, WA, Columbia County, WA, Garfield County, WA, Klickitat County, WA, Walla Walla County, WA, Yakima County, WA

The radar

The Pendleton radar (KPDT), 20 km from the middle of the area, began a volume at 19:57 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 459Aug 12, 1:35 PM PDT

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 8.0 hours before the alert went out and 281 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 3158 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 12, 1:34 PM PDT	Severe Thunderstorm Watch	SPC	Benewah, Bonner, Kootenai, Latah, Nez Perce, Shoshone	6 hr
Aug 12, 1:37 PM PDT	Mesoscale Discussion	SPC	Blaine, Camas, Cassia, Elmore, Gooding, Jerome and 4 more	53 min

Nearby

Mesoscale Discussions in Oregon, 2014 Mesoscale Discussions in Washington, 2014 Mesoscale Discussions in Idaho, 2014 Every mesoscale discussion in 2014

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.