Alert archive / Montana / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 5, NWS Great Falls, MT

May 18, 2020Chouteau County, Fergus County, Judith Basin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at May 18, 2020, 11:44 PM MDT for Chouteau County, Fergus County, Judith Basin County, Montana. It was in force for 46 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: May 18, 2020, 11:44 PM MDT (05:44 UTC)
Expired: May 19, 2020, 12:30 AM MDT
In force: 46 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Chouteau County, MT, Fergus County, MT, Judith Basin County, MT

The radar

The Great Falls radar (KTFX), 106 km from the middle of the area, began a volume at 05:44 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

Great_falls, MT (KTFX), launched 00:00Z, 5.7 hours before the alert went out and 48 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 3 J/kg
Mixed-layer CIN: -176 J/kg
Mixed-layer LCL: 1512 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 270 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at May 18, 11:20 PM MDT, 24 minutes earlier.

Area forecast discussion, May 18, 11:20 PM MDT, 24 minutes before

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In the hours before

Special weather statement, May 18, 10:37 PM MDT, 1 hour 7 minutes before

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Special weather statement, May 18, 10:45 PM MDT, 59 minutes before

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Local storm report, May 18, 10:56 PM MDT, 48 minutes before

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Special weather statement, May 18, 11:19 PM MDT, 25 minutes before

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Special weather statement, May 18, 11:29 PM MDT, 15 minutes before

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Local storm report, May 18, 11:35 PM MDT, 9 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 18, 6:11 PM MDT	Special Weather Statement	TFX	Lewis and Clark	49 min
May 18, 6:31 PM MDT	Special Weather Statement	TFX	Lewis and Clark	44 min
May 18, 6:34 PM MDT	Special Weather Statement	TFX	Fergus	26 min
May 18, 6:36 PM MDT	Special Weather Statement	TFX	Chouteau	24 min
May 18, 6:48 PM MDT	Special Weather Statement	TFX	Judith Basin	27 min
May 18, 6:50 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	25 min
May 18, 6:54 PM MDT	Special Weather Statement	TFX	Fergus	36 min
May 18, 7:02 PM MDT	Special Weather Statement	TFX	Fergus	43 min
May 18, 7:12 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Lewis and Clark	33 min
May 18, 7:22 PM MDT	Special Weather Statement	TFX	Teton	38 min
May 18, 7:29 PM MDT	Special Weather Statement	TFX	Fergus	31 min
May 18, 7:37 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Lewis and Clark, Teton	23 min
May 18, 7:53 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Teton	26 min
May 18, 8:02 PM MDT	Special Weather Statement	TFX	Teton	28 min
May 18, 8:16 PM MDT	Special Weather Statement	TFX		29 min
May 18, 8:18 PM MDT	Special Weather Statement	TFX	Judith Basin	27 min
May 18, 8:34 PM MDT	Special Weather Statement	TFX		41 min
May 18, 8:46 PM MDT	Special Weather Statement	TFX	Fergus	29 min
May 18, 8:47 PM MDT	Special Weather Statement	TFX	Chouteau	43 min
May 18, 9:03 PM MDT	Special Weather Statement	TFX	Cascade	27 min
May 18, 9:27 PM MDT	Special Weather Statement	TFX		48 min
May 18, 9:37 PM MDT	Special Weather Statement	TFX	Hill	38 min
May 18, 10:16 PM MDT	Special Weather Statement	TFX	Meagher	29 min
May 18, 10:22 PM MDT	Special Weather Statement	TFX	Cascade	38 min
May 18, 10:37 PM MDT	Special Weather Statement	TFX	Beaverhead, Gallatin, Madison	38 min
May 18, 10:45 PM MDT	Special Weather Statement	TFX	Judith Basin	45 min
May 18, 11:19 PM MDT	Special Weather Statement	TFX	Deer Lodge	26 min
May 18, 11:29 PM MDT	Special Weather Statement	TFX	Judith Basin	46 min
May 19, 12:38 AM MDT	Special Weather Statement	TFX	Blaine	37 min
May 19, 1:57 PM MDT	Special Weather Statement	TFX	Ravalli	18 min
May 19, 2:31 PM MDT	Special Weather Statement	TFX	Broadwater	29 min
May 19, 2:50 PM MDT	Special Weather Statement	TFX	Silver Bow	40 min
May 19, 2:58 PM MDT	Special Weather Statement	TFX	Meagher	47 min
May 19, 3:57 PM MDT	Special Weather Statement	TFX	Lewis and Clark	33 min
May 19, 4:06 PM MDT	Special Weather Statement	TFX	Judith Basin	24 min
May 19, 4:28 PM MDT	Special Weather Statement	TFX	Judith Basin	47 min
May 19, 4:39 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Judith Basin	36 min
May 19, 4:41 PM MDT	Special Weather Statement	TFX	Lewis and Clark	34 min
May 19, 5:15 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	30 min
May 19, 5:21 PM MDT	Special Weather Statement	TFX	Lewis and Clark	24 min
May 19, 5:57 PM MDT	Special Weather Statement	TFX	Fergus	33 min

Nearby

Severe Thunderstorm Warnings in Montana, 2020 Every 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.