Alert archive / Montana / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 166

June 9, 201820 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jun 9, 2018, 1:46 PM MDT for 20 counties in Montana. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 9, 2018, 1:46 PM MDT (19:46 UTC)
Expired
Jun 9, 2018, 9:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
65 kt

Counties Blaine County, MT, Broadwater County, MT, Cascade County, MT, Chouteau County, MT, Deer Lodge County, MT, Fergus County, MT, Flathead County, MT, Glacier County, MT, Granite County, MT, Hill County, MT, Jefferson County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Liberty County, MT, Meagher County, MT, Pondera County, MT, Powell County, MT, Silver Bow County, MT, Teton County, MT, Toole County, MT

The radar

The Missoula radar (KMSX), 78 km from the middle of the area, began a volume at 19:50 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
5%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
50%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 9, 2:37 PM MDTSevere Thunderstorm WarningTFXLewis and Clark, Pondera, Teton23 min
Jun 9, 3:27 PM MDTSevere Thunderstorm WarningMSOGranite, Powell33 min
Jun 9, 6:35 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus, Judith Basin40 min
Jun 9, 7:30 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin30 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 7.8 hours before the alert went out and 183 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, Great_falls, MT at 12:00Z on 2018-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 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, Great_falls, MT at 12:00Z on 2018-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 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
12 J/kg
Mixed-layer CIN
-295 J/kg
Mixed-layer LCL
2250 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 9, 1:06 PM MDTMesoscale DiscussionSPCCascade, Deer Lodge, Flathead, Glacier, Granite, Lake and 8 more114 min
Jun 9, 2:50 PM MDTMesoscale DiscussionSPCCarter, Powder River2 hr
Jun 9, 4:53 PM MDTMesoscale DiscussionSPCBroadwater, Cascade, Chouteau, Deer Lodge, Flathead, Glacier and 15 more97 min

Nearby

Severe Thunderstorm Watches in Montana, 2018Every severe thunderstorm watch 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.