Alert archive / Montana / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 11, NWS Great Falls, MT

May 30, 2018Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at May 30, 2018, 3:20 PM MDT for Fergus County, Montana. It was in force for 40 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 30, 2018, 3:20 PM MDT (21:20 UTC)
Expired: May 30, 2018, 4:00 PM MDT
In force: 40 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County Fergus County, MT

The radar

The Billings radar (KBLX), 164 km from the middle of the area, began a volume at 21:22 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 12:00Z, 9.3 hours before the alert went out and 106 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: 49 J/kg
Mixed-layer CIN: -231 J/kg
Mixed-layer LCL: 1440 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 79 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 30, 11:10 AM MDT, 4 hours 10 minutes earlier.

Area forecast discussion, May 30, 11:10 AM MDT, 4 hours 10 minutes before

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In the hours before

Special weather statement, May 30, 1:57 PM MDT, 1 hour 23 minutes before

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Special weather statement, May 30, 2:34 PM MDT, 46 minutes before

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Special weather statement, May 30, 2:59 PM MDT, 21 minutes before

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Special weather statement, May 30, 3:03 PM MDT, 17 minutes before

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Special weather statement, May 30, 3:03 PM MDT, 17 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 29, 8:50 PM MDT	Areal Flood Warning	TFX	Blaine, Fergus	14 hr
May 30, 4:43 AM MDT	Special Weather Statement	TFX	Pondera	47 min
May 30, 10:23 AM MDT	Areal Flood Warning	TFX	Blaine, Fergus	4 days
May 30, 1:11 PM MDT	Areal Flood Warning	TFX	Broadwater	5 days
May 30, 1:57 PM MDT	Special Weather Statement	TFX	Beaverhead	33 min
May 30, 2:34 PM MDT	Special Weather Statement	TFX	Jefferson	26 min
May 30, 2:59 PM MDT	Special Weather Statement	TFX	Broadwater	31 min
May 30, 3:03 PM MDT	Special Weather Statement	TFX	Jefferson	27 min
May 30, 3:33 PM MDT	Special Weather Statement	TFX	Broadwater	27 min
May 30, 3:39 PM MDT	Special Weather Statement	TFX	Broadwater, Jefferson	36 min
May 30, 4:22 PM MDT	Special Weather Statement	TFX	Broadwater, Meagher	23 min
May 30, 4:46 PM MDT	Special Weather Statement	TFX	Fergus	44 min
May 30, 4:50 PM MDT	Special Weather Statement	TFX	Wheatland	40 min
May 30, 5:03 PM MDT	Special Weather Statement	TFX	Fergus	42 min
May 30, 5:45 PM MDT	Special Weather Statement	TFX	Cascade	30 min
May 30, 5:48 PM MDT	Special Weather Statement	TFX	Fergus	42 min
May 30, 5:55 PM MDT	Special Weather Statement	TFX	Madison	35 min

Nearby

Severe Thunderstorm Warnings in Montana, 2018 Every 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.