Alert archive / Oregon / Mesoscale Discussions in 2017

Mesoscale Discussion 1628

September 7, 201710 counties in Oregon

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2017, 2:38 PM PDT for 10 counties in Oregon. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Sep 7, 2017, 2:38 PM PDT (21:38 UTC)
Expired
Sep 7, 2017, 5:15 PM PDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Clackamas County, OR, Crook County, OR, Deschutes County, OR, Douglas County, OR, Jefferson County, OR, Klamath County, OR, Lane County, OR, Linn County, OR, Marion County, OR, Wasco County, OR

The radar

The Medford radar (KMAX), 196 km from the middle of the area, began a volume at 21:39 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

Salem/Mcnary, OR (KSLE), launched 12:00Z, 9.6 hours before the alert went out and 156 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, Salem/Mcnary, OR at 12:00Z on 2017-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Salem/Mcnary, OR at 12:00Z on 2017-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 56 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1232 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
56 m²/s²
0-3 km storm-relative helicity
22 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 Oregon, 2017Every mesoscale discussion in 2017

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.