Alert archive / Montana / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 103, NWS Glasgow, MT

July 21, 2018Roosevelt County, Sheridan County, Montana

NWS Glasgow, MT issued this severe thunderstorm warning at Jul 21, 2018, 3:11 PM MDT for Roosevelt County, Sheridan County, Montana. It was in force for 79 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
Jul 21, 2018, 3:11 PM MDT (21:11 UTC)
Expired
Jul 21, 2018, 4:30 PM MDT
In force
79 min
Issued by
NWS Glasgow, MT
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Roosevelt County, MT, Sheridan County, MT

The radar

The Glasgow radar (KGGW), 142 km from the middle of the area, began a volume at 21:12 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

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 9.2 hours before the alert went out and 140 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, Glasgow Intl Airport, MT at 12:00Z on 2018-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 637 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, Glasgow Intl Airport, MT at 12:00Z on 2018-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 294 square meters per square second.1939587897Sfc1 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
637 J/kg
Mixed-layer CIN
-421 J/kg
Mixed-layer LCL
1463 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
294 m²/s²
0-3 km storm-relative helicity
287 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The office that day

Everything else NWS Glasgow, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 7:25 PM MDTSpecial Weather StatementGGWValley65 min
Jul 21, 11:43 AM MDTSpecial Weather StatementGGWValley47 min
Jul 21, 12:04 PM MDTSevere Thunderstorm WarningGGWDaniels, Valley56 min
Jul 21, 12:54 PM MDTSevere Thunderstorm WarningGGWDaniels, Valley66 min
Jul 21, 1:19 PM MDTSevere Thunderstorm WarningGGWDaniels, Roosevelt, Sheridan56 min
Jul 21, 1:28 PM MDTSevere Thunderstorm WarningGGWDaniels62 min
Jul 21, 2:17 PM MDTSevere Thunderstorm WarningGGWDaniels, Roosevelt, Sheridan58 min
Jul 21, 3:00 PM MDTLake Wind AdvisoryGGWGarfield, McCone, Petroleum, Phillips, Valley29 hr
Jul 21, 4:20 PM MDTSevere Thunderstorm WarningGGWRichland, Roosevelt40 min
Jul 21, 4:53 PM MDTSevere Thunderstorm WarningGGWRichland, Roosevelt67 min

Nearby

Severe Thunderstorm Warnings in Montana, 2018Every severe thunderstorm warning 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.