Alert archive / Montana / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 51, NWS Great Falls, MT

August 3, 2020Gallatin County, Madison County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 3, 2020, 5:49 PM MDT for Gallatin County, Madison County, Montana. It was in force for 26 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 3, 2020, 5:49 PM MDT (23:49 UTC)
Expired
Aug 3, 2020, 6:15 PM MDT
In force
26 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Gallatin County, MT, Madison County, MT

The radar

The Great Falls radar (KTFX), 227 km from the middle of the area, began a volume at 23:51 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, 11.8 hours before the alert went out and 238 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 2020-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 597 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 2020-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 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
597 J/kg
Mixed-layer CIN
-290 J/kg
Mixed-layer LCL
2351 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
51 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 Aug 3, 5:48 PM MDT, 1 minute earlier.

Area forecast discussion, Aug 3, 5:48 PM MDT, 1 minute before
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In the hours before

Special weather statement, Aug 3, 5:13 PM MDT, 36 minutes before
Special Weather Statement
National Weather Service Great Falls MT
513 PM MDT Mon Aug 3 2020

MTZ013-032345-
Chouteau-
513 PM MDT Mon Aug 3 2020

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL CHOUTEAU COUNTY...

At 512 PM MDT, a strong thunderstorm was located 14 miles west of
Fort Benton, moving east at 25 mph.

Winds in excess of 40 mph and penny size hail are possible with this
storm.

Locations impacted include...
Fort Benton, Carter and Floweree.

This includes Highway 87 between mile markers 22 and 42.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding.

Cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4770 11105 4781 11107 4790 11067 4769 11064
TIME...MOT...LOC 2312Z 260DEG 26KT 4777 11095

RCG
Special weather statement, Aug 3, 5:21 PM MDT, 28 minutes before
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Special weather statement, Aug 3, 5:28 PM MDT, 21 minutes before
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Special weather statement, Aug 3, 5:34 PM MDT, 15 minutes before
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Special weather statement, Aug 3, 5:36 PM MDT, 13 minutes before
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Special weather statement, Aug 3, 5:46 PM MDT, 3 minutes before
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      <p id="message1">
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 3, 8:07 AM MDTSpecial Weather StatementTFXTeton38 min
Aug 3, 8:30 AM MDTSpecial Weather StatementTFXTeton30 min
Aug 3, 8:50 AM MDTSpecial Weather StatementTFXCascade40 min
Aug 3, 9:26 AM MDTSpecial Weather StatementTFXChouteau64 min
Aug 3, 10:07 AM MDTSpecial Weather StatementTFXChouteau53 min
Aug 3, 10:52 AM MDTSpecial Weather StatementTFXChouteau53 min
Aug 3, 10:59 AM MDTSpecial Weather StatementTFXChouteau46 min
Aug 3, 11:48 AM MDTSpecial Weather StatementTFXChouteau57 min
Aug 3, 12:19 PM MDTSevere Thunderstorm WarningTFXJudith Basin41 min
Aug 3, 12:32 PM MDTSpecial Weather StatementTFXBlaine43 min
Aug 3, 1:02 PM MDTSpecial Weather StatementTFXFergus43 min
Aug 3, 1:40 PM MDTSpecial Weather StatementTFXFergus65 min
Aug 3, 2:16 PM MDTSpecial Weather StatementTFXBlaine44 min
Aug 3, 2:27 PM MDTSpecial Weather StatementTFXFergus48 min
Aug 3, 2:36 PM MDTSpecial Weather StatementTFX24 min
Aug 3, 3:23 PM MDTSpecial Weather StatementTFX22 min
Aug 3, 3:40 PM MDTSpecial Weather StatementTFXMadison35 min
Aug 3, 4:27 PM MDTSpecial Weather StatementTFXMadison48 min
Aug 3, 4:41 PM MDTSpecial Weather StatementTFXChouteau34 min
Aug 3, 4:51 PM MDTSpecial Weather StatementTFXJudith Basin24 min
Aug 3, 5:03 PM MDTSpecial Weather StatementTFXTeton27 min
Aug 3, 5:13 PM MDTSpecial Weather StatementTFXChouteau32 min
Aug 3, 5:21 PM MDTSpecial Weather StatementTFX39 min
Aug 3, 5:28 PM MDTSpecial Weather StatementTFXGallatin, Madison47 min
Aug 3, 5:34 PM MDTSpecial Weather StatementTFXLiberty26 min
Aug 3, 5:36 PM MDTSpecial Weather StatementTFXFergus24 min
Aug 3, 5:46 PM MDTSpecial Weather StatementTFXChouteau29 min

Nearby

Severe Thunderstorm Warnings in Montana, 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.