Alert archive / Idaho / Mesoscale Discussions in 2018

Mesoscale Discussion 1309

August 17, 201824 counties in Idaho; Beaverhead County, Ravalli County, Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2018, 1:41 PM MDT for 24 counties in Idaho; Beaverhead County, Ravalli County, Montana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 17, 2018, 1:41 PM MDT (19:41 UTC)
Expired
Aug 17, 2018, 3:45 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 26 counties

Ada County, ID, Adams County, ID, Blaine County, ID, Boise County, ID, Butte County, ID, Camas County, ID, Canyon County, ID, Cassia County, ID, Clark County, ID, Custer County, ID, Elmore County, ID, Gem County, ID, Gooding County, ID, Idaho County, ID, Jerome County, ID, Lemhi County, ID, Lincoln County, ID, Minidoka County, ID, Owyhee County, ID, Payette County, ID, Power County, ID, Twin Falls County, ID, Valley County, ID, Washington County, ID, Beaverhead County, MT, Ravalli County, MT

The radar

The Boise radar (KCBX), 117 km from the middle of the area, began a volume at 19:43 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

Elko, NV (KLKN), launched 12:00Z, 7.7 hours before the alert went out and 353 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, Elko, NV at 12:00Z on 2018-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Elko, NV at 12:00Z on 2018-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
1 J/kg
Mixed-layer CIN
-323 J/kg
Mixed-layer LCL
2502 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
48 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 Idaho, 2018Mesoscale Discussions in Montana, 2018Every mesoscale discussion in 2018

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.