Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

June 24, 2021Fergus County, Montana

NWS Great Falls, MT issued this special weather statement at Jun 24, 2021, 5:16 PM MDT for Fergus County, Montana. It was in force for 44 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
Jun 24, 2021, 5:16 PM MDT (23:16 UTC)
Expired
Jun 24, 2021, 6:00 PM MDT
In force
44 min
Issued by
NWS Great Falls, MT

County Fergus County, MT

The radar

The Billings radar (KBLX), 112 km from the middle of the area, began a volume at 23:16 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, 11.3 hours before the alert went out and 145 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 2021-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 10 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 2021-06-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 105 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
10 J/kg
Mixed-layer CIN
-138 J/kg
Mixed-layer LCL
2437 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
105 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Jun 24, 2:30 PM MDT, 2 hours 46 minutes earlier.

Area forecast discussion, Jun 24, 2:30 PM MDT, 2 hours 46 minutes before
Area Forecast Discussion
National Weather Service Great Falls MT
230 PM MDT Thu Jun 24 2021

.SYNOPSIS...
Scattered showers and thunderstorms will move through the region
tonight, with a few isolated showers possible on Friday and
Saturday, mostly south of Great Falls. On Sunday, warmer air moves
into the region, with the potential for several days of hot
temperatures by the middle portion of next week.

&&

.DISCUSSION...
Tonight thru Saturday...With an upper level disturbance moving
through the region behind a cool front, scattered
showers/thunderstorms have developed. There is a small chance for
an isolated severe storm over Central MT, mostly before 8 PM this
evening. Otherwise, most of the showers/storms should diminish
after Midnight. For Friday and Saturday, expect a few light
showers to redevelop, mostly south and east of Great Falls, as the
northerly flow aloft resides over the area. Any precipitation
will be light and isolated.

Sunday through Thursday...Expect a significant warming trend to
develop by the middle portions of next week. There is the
potential that a few locations could see record high temperatures
by the middle of next week. Overall, the EC model is slower moving
the ridge to the east, as a result, the EC is a bit cooler with
afternoon temperatures than the GFS model. Thus the NBM seems to
have a good handle on temperatures in the extended, thus no
changes to temperatures today. Afternoon highs might not be quite
as hot as previously thought, but still afternoon highs of 95 to
100 degrees look likely. With these temperatures, a heat advisory
might be needed for portions of the region next week, depending on
how colling develops at night. Brusda

&&

.AVIATION...
1150 AM MDT Thu Jun 24 2021 (24/18Z TAF period)

Main concern this afternoon is showers/thunderstorms moving through
the region. Expect periods of precipitation through 02z, before the
precipitation gradually diminishes. Mid/high level clouds will
linger into Friday morning. Overall VFR conditions will prevail, but
some MVFR conditions are possible for a short time in/near any areas
of precipitation. Brusda

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  78  56  81 /  30  10   0  10
CTB  46  78  56  81 /  30  10   0   0
HLN  54  82  57  84 /  20  10   0   0
BZN  49  80  49  80 /  30  20   0  10
WYS  40  72  41  71 /  40  30   0  10
DLN  48  77  49  79 /  20  10   0   0
HVR  47  80  57  84 /  20   0   0   0
LWT  48  75  52  76 /  40  10  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.

&&

http://www.weather.gov/greatfalls

In the hours before

Special weather statement, Jun 24, 2:05 PM MDT, 3 hours 11 minutes before
Special Weather Statement
National Weather Service Great Falls MT
205 PM MDT Thu Jun 24 2021

MTZ012-242045-
Cascade-
205 PM MDT Thu Jun 24 2021

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

At 203 PM MDT, a strong thunderstorm was located 13 miles west of
Cascade, moving east at 20 mph.

Winds in excess of 40 mph and half inch hail are possible with this
storm.

Locations impacted include...
Cascade and Tower Rock State Park.

This includes Interstate 15 between mile markers 246 and 257.

If outdoors, consider seeking shelter inside a building.

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

Frequent 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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in Great Falls.

LAT...LON 4723 11204 4731 11204 4732 11168 4713 11170
TIME...MOT...LOC 2003Z 273DEG 16KT 4726 11200

TPP
Special weather statement, Jun 24, 3:57 PM MDT, 1 hour 19 minutes before
Special Weather Statement
National Weather Service Great Falls MT
357 PM MDT Thu Jun 24 2021

MTZ048-242230-
Southern Rocky Mountain Front-
357 PM MDT Thu Jun 24 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN LEWIS AND CLARK AND
CENTRAL TETON COUNTIES...

At 356 PM MDT, a strong thunderstorm was located 10 miles west of
Choteau, moving southeast at 20 mph.

Winds in excess of 30 mph and half inch hail are possible with this
storm.

Locations impacted include...
Choteau and Pishkun Reservoir.

This includes the following highways...
 Highway 287 between mile markers 57 and 64.
 Highway 89 between mile markers 38 and 45.

If outdoors, consider seeking shelter inside a building.

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

Frequent 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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in Great Falls.

LAT...LON 4779 11256 4790 11236 4780 11208 4757 11243
TIME...MOT...LOC 2156Z 323DEG 19KT 4779 11241

TPP
Special weather statement, Jun 24, 4:07 PM MDT, 1 hour 9 minutes before
Special Weather Statement
National Weather Service Great Falls MT
407 PM MDT Thu Jun 24 2021

MTZ054-242230-
Meagher-
407 PM MDT Thu Jun 24 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN MEAGHER COUNTY...

At 406 PM MDT, a strong thunderstorm was located 29 miles southeast
of Cascade, moving east at 20 mph.

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

This storm will remain over mainly rural areas of northwestern
Meagher County.

If outdoors, consider seeking shelter inside a building.

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

Frequent 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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in Great Falls.

LAT...LON 4687 11154 4698 11150 4700 11108 4670 11130
TIME...MOT...LOC 2206Z 289DEG 18KT 4690 11137

TPP
Special weather statement, Jun 24, 4:25 PM MDT, 51 minutes before
Special Weather Statement
National Weather Service Great Falls MT
425 PM MDT Thu Jun 24 2021

MTZ048-242300-
Southern Rocky Mountain Front-
425 PM MDT Thu Jun 24 2021

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL LEWIS AND CLARK AND
SOUTH CENTRAL TETON COUNTIES...

At 425 PM MDT, a strong thunderstorm was located near Augusta, or 22
miles southwest of Choteau, moving southeast at 15 mph.

Winds in excess of 30 mph and half inch hail are possible with this
storm.

Locations impacted include...
Augusta.

This includes Highway 287 between mile markers 35 and 49.

If outdoors, consider seeking shelter inside a building.

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

Frequent 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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in Great Falls.

LAT...LON 4754 11253 4763 11240 4759 11210 4736 11247
TIME...MOT...LOC 2225Z 309DEG 15KT 4755 11245

TPP
Special weather statement, Jun 24, 5:16 PM 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
Jun 24, 2:05 PM MDTSpecial Weather StatementTFXCascade40 min
Jun 24, 3:57 PM MDTSpecial Weather StatementTFXTeton33 min
Jun 24, 4:07 PM MDTSpecial Weather StatementTFXMeagher23 min
Jun 24, 4:25 PM MDTSpecial Weather StatementTFXTeton35 min
Jun 24, 4:29 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin31 min
Jun 24, 4:55 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin35 min
Jun 24, 5:29 PM MDTSevere Thunderstorm WarningTFXFergus31 min
Jun 24, 5:59 PM MDTSevere Thunderstorm WarningTFXFergus31 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.