Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

July 6, 2021Fergus County, Montana

NWS Great Falls, MT issued this special weather statement at Jul 6, 2021, 3:42 AM MDT for Fergus County, Montana. It was in force for 33 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 6, 2021, 3:42 AM MDT (09:42 UTC)
Expired
Jul 6, 2021, 4:15 AM MDT
In force
33 min
Issued by
NWS Great Falls, MT

County Fergus County, MT

The radar

The Great Falls radar (KTFX), 139 km from the middle of the area, began a volume at 09:43 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, 9.7 hours before the alert went out and 81 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 00:00Z on 2021-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 435 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 00:00Z on 2021-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
435 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
1792 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Jul 6, 3:32 AM MDT, 10 minutes earlier.

Area forecast discussion, Jul 6, 3:32 AM MDT, 10 minutes before
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In the hours before

Special weather statement, Jul 6, 2:16 AM MDT, 1 hour 26 minutes before
Special Weather Statement
National Weather Service Great Falls MT
216 AM MDT Tue Jul 6 2021

MTZ011-061045-
Hill-
Including the cities of Havre, Rocky Boy, and Rudyard
216 AM MDT Tue Jul 6 2021

Widespread moderate to heavy rainfall is occurring across Hill
County early Tuesday morning. The rain has developed as an area of
thunderstorms merged into an organized convective weather system.
Lightning is ongoing as well, and small hail is possible at times.
Rainfall amounts of one-half to two inches are possible through
5am Tuesday. Do not attempt to drive through flooded roadways.
Access to unpaved rural roads may be difficult in some areas
Tuesday morning.
Special weather statement, Jul 6, 2:22 AM MDT, 1 hour 20 minutes before
Special Weather Statement
National Weather Service Great Falls MT
222 AM MDT Tue Jul 6 2021

MTZ013-060900-
Chouteau-
222 AM MDT Tue Jul 6 2021

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

At 221 AM MDT, a strong thunderstorm was located 15 miles northeast
of Fort Benton, moving east at 60 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
Big Sandy, Boneau, St. Pierre, Parker School, Loma and Virgelle.

This includes Highway 87 between mile markers 44 and 89.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4822 10984 4822 10973 4813 10973 4813 10953
      4780 10954 4787 11091 4831 11008 4830 10985
TIME...MOT...LOC 0821Z 272DEG 50KT 4796 11039

PN
Local storm report, Jul 6, 2:45 AM MDT, 57 minutes before
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Local storm report, Jul 6, 2:46 AM MDT, 56 minutes before
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Special weather statement, Jul 6, 3:00 AM MDT, 42 minutes before
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Special weather statement, Jul 6, 3:42 AM MDT, 0 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 6:29 PM MDTSpecial Weather StatementTFXGallatin, Madison31 min
Jul 5, 7:04 PM MDTSpecial Weather StatementTFXGallatin26 min
Jul 5, 7:47 PM MDTSpecial Weather StatementTFXBeaverhead28 min
Jul 5, 9:16 PM MDTSpecial Weather StatementTFXGlacier44 min
Jul 5, 9:57 PM MDTSevere Thunderstorm WarningTFXGlacier33 min
Jul 5, 10:25 PM MDTSevere Thunderstorm WarningTFXGlacier, Toole50 min
Jul 5, 11:12 PM MDTSpecial Weather StatementTFXToole63 min
Jul 6, 12:14 AM MDTSpecial Weather StatementTFXLiberty61 min
Jul 6, 12:42 AM MDTSpecial Weather StatementTFXChouteau33 min
Jul 6, 1:15 AM MDTSpecial Weather StatementTFXLiberty60 min
Jul 6, 1:18 AM MDTSpecial Weather StatementTFXChouteau27 min
Jul 6, 1:44 AM MDTSpecial Weather StatementTFXChouteau46 min
Jul 6, 2:22 AM MDTSpecial Weather StatementTFXChouteau38 min
Jul 6, 3:00 AM MDTSpecial Weather StatementTFXChouteau45 min
Jul 6, 4:15 AM MDTSpecial Weather StatementTFXFergus45 min
Jul 6, 3:37 PM MDTSpecial Weather StatementTFXGlacier23 min
Jul 6, 3:55 PM MDTSpecial Weather StatementTFXGlacier35 min
Jul 6, 4:21 PM MDTSpecial Weather StatementTFXGlacier24 min
Jul 6, 4:27 PM MDTSpecial Weather StatementTFXMusselshell33 min
Jul 6, 4:37 PM MDTSpecial Weather StatementTFXFergus23 min
Jul 6, 4:40 PM MDTSevere Thunderstorm WarningTFXGlacier35 min
Jul 6, 4:42 PM MDTSpecial Weather StatementTFXBlaine33 min
Jul 6, 5:14 PM MDTSevere Thunderstorm WarningTFXGlacier, Toole31 min
Jul 6, 5:15 PM MDTSpecial Weather StatementTFXBlaine30 min
Jul 6, 5:45 PM MDTSpecial Weather StatementTFXToole30 min
Jul 6, 5:46 PM MDTSevere Thunderstorm WarningTFXBlaine29 min

Nearby

Special Weather Statements in Montana, 2021Every special weather statement in 2021

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.