Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

August 26, 2021Judith Basin County, Montana

NWS Great Falls, MT issued this special weather statement at Aug 26, 2021, 3:57 PM MDT for Judith Basin 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
Aug 26, 2021, 3:57 PM MDT (21:57 UTC)
Expired
Aug 26, 2021, 4:30 PM MDT
In force
33 min
Issued by
NWS Great Falls, MT
Hail
0.25 in
Wind
55

County Judith Basin County, MT

The radar

The Great Falls radar (KTFX), 55 km from the middle of the area, began a volume at 21:56 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 12:00Z, 10.0 hours before the alert went out and 22 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 2021-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 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 2021-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 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
67 J/kg
Mixed-layer CIN
-300 J/kg
Mixed-layer LCL
1944 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
85 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

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 Aug 26, 2:51 PM MDT, 1 hour 6 minutes earlier.

Area forecast discussion, Aug 26, 2:51 PM MDT, 1 hour 6 minutes before
Area Forecast Discussion
National Weather Service Great Falls MT
251 PM MDT Thu Aug 26 2021

.SYNOPSIS...

Scattered showers and thunderstorms will dissipate through the
evening hours. Another weather system will produce periods of rain
over the Northern Rockies tonight, then spread through central
Montana on Friday. Afternoon temperatures trend cooler for Friday,
then return to near average through early next week.

&&

.DISCUSSION...

An upper level shortwave trough presently over Southwest Montana
is beginning to initiate convection across portions of Central MT.
The arrival of this disturbance coincides with afternoon peak
heating, producing weak to moderate instability. Scattered showers
and thunderstorms will continue through the evening, a few of
which could produce gusty winds and small hail. The best chance
for stronger storms this afternoon remains over eastern portions
of Fergus county. This round of thunderstorms will dissipate or
move away to the east through this evening.

Temperatures trend cooler tonight with partial clearing. With
lowering heights and increasing clouds again on Friday,
temperatures will drop about 10 degrees below average, into the
upper 60s and lower 70s Friday. The next shortwave trough is a bit
stronger arriving Friday, producing periods of rain over the
Northern Rockies, with rain showers and isolated general
thunderstorms spreading across N-central and Central Montana
through the day on Friday. Precipitation wanes overnight in to
Saturday morning as the weather system moves away to the east. PN

Saturday through Monday...Ridging over the region will provide
generally fair weather through the weekend, along with a warming
trend. A few light showers are possible early Saturday, mainly
north of Highway 2, otherwise dry conditions should prevail.
Afternoon temperatures are likely to be above normal for most
locations on Sunday/Monday.

Tuesday through Thursday...The GFS/EC models continue to differ
in terms of timing/amount of precipitation with the next trof
towards the middle of next week. The GFS is slower with the
approach of the trof, thus warmer with temperatures towards the
middle of next week. Overall the NBM's blend solution looks good
for this period. Brusda

&&

.AVIATION...
1205 PM MDT Thu Aug 26 2021 (26/18Z TAF period)

Showers are approaching the Divide and will continue moving east
into the forecast area this afternoon. The showers/storms today will
be fairly quick moving, so they will not last long at any one point.
Still some brief MVFR conditions will be possible. Some stronger
storms may develop and possibly contain gusty winds/hail and brief
heavy downpours, mostly for areas south and east of a KHLN to KGTF
to KHVR line. Expect partial clearing behind the storms, generally
after 27/03z. Then a Pacific cold front moves through the region and
brings more scattered showers and west to northwesterly breezes on
Friday. -RCG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  70  45  73 /  20  50  20  10
CTB  49  64  45  70 /  10  70  30  10
HLN  53  71  47  75 /  20  60  10   0
BZN  46  70  42  71 /  20  60  20   0
WYS  35  65  32  66 /  10  30  20   0
DLN  44  69  39  70 /  10  30  10   0
HVR  52  73  48  73 /  30  50  20  10
LWT  48  65  44  68 /  70  70  10  10

&&

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

http://www.weather.gov/greatfalls

In the hours before

Special weather statement, Aug 26, 2:04 PM MDT, 1 hour 53 minutes before
Special Weather Statement
National Weather Service Great Falls MT
204 PM MDT Thu Aug 26 2021

MTZ054-262030-
Meagher MT-
204 PM MDT Thu Aug 26 2021

...A strong thunderstorm will impact portions of northwestern
Meagher County through 230 PM MDT...

At 203 PM MDT, Doppler radar was tracking a strong thunderstorm 31
miles northwest of White Sulphur Springs, moving east at 10 mph.

HAZARD...Winds up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of northwestern
Meagher and southeastern Cascade Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4700 11136 4701 11117 4709 11116 4709 11109
      4704 11108 4703 11111 4700 11104 4683 11097
      4684 11135 4699 11139
TIME...MOT...LOC 2003Z 260DEG 7KT 4693 11126

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

RCG
Special weather statement, Aug 26, 2:26 PM MDT, 1 hour 31 minutes before
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Special weather statement, Aug 26, 2:58 PM MDT, 59 minutes before
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Local storm report, Aug 26, 3:03 PM MDT, 54 minutes before
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Special weather statement, Aug 26, 3:32 PM MDT, 25 minutes before
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Special weather statement, Aug 26, 3:57 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Great Falls MT
357 PM MDT Thu Aug 26 2021

MTZ012-013-050-262230-
Chouteau MT-Cascade MT-Judith Basin MT-
357 PM MDT Thu Aug 26 2021

...A strong thunderstorm will impact portions of northwestern Judith
Basin, southwestern Chouteau and east central Cascade Counties
through 430 PM MDT...

At 356 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Belt, or 28 miles west of Stanford, moving
northeast at 15 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Geyser and Raynesford.

This includes the following highways...
 Highway 200 between mile markers 0 and 27.
 Highway 89 between mile markers 53 and 56, and between mile markers
64 and 71.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 4713 11082 4728 11097 4760 11069 4723 11024
TIME...MOT...LOC 2156Z 241DEG 13KT 4725 11081

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

RCG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 25, 6:27 PM MDTSpecial Weather StatementTFXJefferson48 min
Aug 25, 6:34 PM MDTSpecial Weather StatementTFXMadison26 min
Aug 25, 8:26 PM MDTSpecial Weather StatementTFXMadison34 min
Aug 25, 8:32 PM MDTSpecial Weather StatementTFXMeagher28 min
Aug 26, 1:10 PM MDTSpecial Weather StatementTFXLewis and Clark35 min
Aug 26, 1:46 PM MDTSpecial Weather StatementTFXLewis and Clark29 min
Aug 26, 2:04 PM MDTSpecial Weather StatementTFXCascade26 min
Aug 26, 2:26 PM MDTSpecial Weather StatementTFXFergus34 min
Aug 26, 2:58 PM MDTSpecial Weather StatementTFXFergus47 min
Aug 26, 3:32 PM MDTSpecial Weather StatementTFXJudith Basin28 min
Aug 26, 4:11 PM MDTSpecial Weather StatementTFXFergus34 min
Aug 26, 4:20 PM MDTSpecial Weather StatementTFXBlaine25 min
Aug 26, 4:31 PM MDTSpecial Weather StatementTFXChouteau29 min
Aug 26, 4:33 PM MDTSpecial Weather StatementTFXFergus27 min
Aug 26, 4:44 PM MDTSpecial Weather StatementTFXFergus31 min
Aug 26, 4:58 PM MDTSpecial Weather StatementTFXFergus32 min
Aug 26, 5:10 PM MDTSpecial Weather StatementTFXFergus35 min
Aug 26, 5:16 PM MDTSpecial Weather StatementTFXChouteau29 min
Aug 26, 5:42 PM MDTSpecial Weather StatementTFXFergus33 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.