Alert archive / Oregon / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 29, NWS Pendleton, OR

August 17, 2020Gilliam County, Morrow County, Oregon

NWS Pendleton, OR issued this severe thunderstorm warning at Aug 17, 2020, 7:01 PM PDT for Gilliam County, Morrow County, Oregon. It was in force for 59 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 17, 2020, 7:01 PM PDT (02:01 UTC)
Expired
Aug 17, 2020, 8:00 PM PDT
In force
59 min
Issued by
NWS Pendleton, OR
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Gilliam County, OR, Morrow County, OR

The radar

The Pendleton radar (KPDT), 88 km from the middle of the area, began a volume at 02:02 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 17, 3:19 PM PDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Boise Airport, ID (KBOI), launched 00:00Z, 2.0 hours before the alert went out and 357 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, Boise Airport, ID at 00:00Z on 2020-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 701 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, Boise Airport, ID at 00:00Z on 2020-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -28 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
701 J/kg
Mixed-layer CIN
-128 J/kg
Mixed-layer LCL
3285 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
-28 m²/s²
0-3 km storm-relative helicity
27 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The office that day

Everything else NWS Pendleton, OR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 5:03 PM PDTSevere Thunderstorm WarningPDTJefferson, Wasco38 min
Aug 17, 5:38 PM PDTSevere Thunderstorm WarningPDTWasco37 min
Aug 17, 6:47 PM PDTSpecial Weather StatementPDTGilliam, Morrow58 min
Aug 17, 8:29 PM PDTSpecial Weather StatementPDTFranklin61 min

Nearby

Severe Thunderstorm Warnings in Oregon, 2020Every severe thunderstorm warning 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.