Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

August 30, 2021Blaine County, Montana

NWS Great Falls, MT issued this special weather statement at Aug 30, 2021, 11:52 PM MDT for Blaine County, Montana. It was in force for 23 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
Aug 30, 2021, 11:52 PM MDT (05:52 UTC)
Expired
Aug 31, 2021, 12:15 AM MDT
In force
23 min
Issued by
NWS Great Falls, MT
Hail
0.00 in
Wind
30

County Blaine County, MT

The radar

The Great Falls radar (KTFX), 178 km from the middle of the area, began a volume at 05:56 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, 5.9 hours before the alert went out and 139 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 2021-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 111 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 2021-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 square meters per square second.19395878Sfc1 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
111 J/kg
Mixed-layer CIN
-83 J/kg
Mixed-layer LCL
3427 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

536 
WWUS85 KTFX 310552
SPSTFX

Special Weather Statement
National Weather Service Great Falls MT
1152 PM MDT Mon Aug 30 2021
 
MTZ011-047-310615-
Hill MT-Blaine MT-
1152 PM MDT Mon Aug 30 2021

...A thunderstorm will impact portions of northwestern Blaine and 
east central Hill Counties through 1215 AM MDT...

At 1151 PM MDT, Doppler radar was tracking a thunderstorm near 
Havre, moving northeast at 45 mph.

HAZARD...Winds in excess of 30 mph and brief heavy rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects.

Locations impacted include...
Havre, Chinook and Lohman. 

This includes the following highways...
 Highway 2 between mile markers 378 and 408.
 Highway 87 between mile markers 103 and 111.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

&&

LAT...LON 4834 10977 4850 10990 4877 10928 4853 10909
TIME...MOT...LOC 0551Z 242DEG 38KT 4846 10974 

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

$$

SC

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 30, 7:19 PM MDTSpecial Weather StatementTFXToole26 min
Aug 30, 7:40 PM MDTSpecial Weather StatementTFXCascade, Chouteau, Fergus, Judith Basin, Meagher35 min
Aug 30, 9:23 PM MDTSpecial Weather StatementTFXBlaine22 min
Aug 30, 9:26 PM MDTSpecial Weather StatementTFXCascade34 min
Aug 30, 9:54 PM MDTSpecial Weather StatementTFXBlaine51 min
Aug 30, 10:05 PM MDTSpecial Weather StatementTFXChouteau25 min
Aug 30, 10:12 PM MDTSpecial Weather StatementTFXCascade33 min
Aug 30, 10:51 PM MDTSpecial Weather StatementTFXBlaine39 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.