Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

July 4, 2021Gallatin County, Montana

NWS Great Falls, MT issued this special weather statement at Jul 4, 2021, 6:34 PM MDT for Gallatin 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 outline as issued.

The facts

Issued: Jul 4, 2021, 6:34 PM MDT (00:34 UTC)
Expired: Jul 4, 2021, 7:00 PM MDT
In force: 26 min
Issued by: NWS Great Falls, MT

County Gallatin County, MT

The radar

The Billings radar (KBLX), 194 km from the middle of the area, began a volume at 00:37 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, 0.6 hours before the alert went out and 232 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 4341 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 13 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 Jul 4, 4:40 PM MDT, 1 hour 54 minutes earlier.

Area forecast discussion, Jul 4, 4:40 PM MDT, 1 hour 54 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
440 PM MDT Sun Jul 4 2021

...UPDATED AVIATION SECTION...

.SYNOPSIS...
Showers and thunderstorms will move through Southwest and Central MT
this evening, while a cool front moves southward from Canada through
North Central MT after Midnight. Overall temperatures will be
above normal all week, with Wednesday likely being the hottest
work day. There will be scattered thunderstorms through Wednesday,
but a significant amount of precipitation is not expected at this
time.

&&

.DISCUSSION...
Tonight through Tuesday...The first round of showers/storms is
exiting the eastern portions of the region at 2 PM, as the next
wave of thunderstorms moves into the western portions of the
region. These storms will move through our region late this
afternoon/evening and could impact firework display, mostly south
of a line from Helena to Lewistown. A wind shift will move
southward through North Central MT, mostly after Midnight. On
Monday, NBM temperatures look on track. I don't think the cloud
cover will be enough to hold temperatures down, along with the dry
soil conditions. In Southwest MT, afternoon temperatures still
look to approach 90 degrees. Temperatures warm to about 4 to 8
degrees above normal on Tuesday afternoon, with a few isolated
showers/thunderstorms possible around Havre/Harlem.

Wednesday through Friday...An upper level disturbance will move
through the region on Wednesday, thus the chances for
thunderstorms look a bit higher on this day. It is hot ahead of
this disturbance, with the airmass cooling a bit for Thu/Fri.
Although afternoon temperatures are likely to remain above
normal.

Saturday and Sunday...Overall expect above normal temperatures
next weekend along with dry conditions, as the upper level ridge
rebuilds over the region. Brusda

&&

.AVIATION...
440 PM MDT Sun Jul 4 2021 (05/00Z TAF period)

VFR conditions are mostly expected through this 24 hour period.
Scattered showers/thunderstorms with periods of MVFR conditions will
move over portions of Central and Southwest Montana through 08z or
so, mainly along and south of a KHLN-KLWT line. A surface wind shift
to the northwest/north will move southward through the Hi-Line
between 06Z and 10Z and over the remainder of the plains between 10Z
and 14Z. Ceilings over the plains will mostly fall to low VFR to
high MVFR through around 18Z or so, but the KCTB could have periods
of IFR ceilings. An isolated shower is possible along this cool
front, but confidence is low at this point that any shower will
affect a terminal. However, another disturbance could bring another
round of scattered showers/thunderstorms to southwest Montana
between 12Z and 20Z. A few isolated showers/thunderstorms may also
redevelop in the wake of this disturbance after 20Z with daytime
heating. -Coulston

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

&&

.FIRE WEATHER...
Thunderstorms are expected over the Central and Southern portions
of the region this evening, as a wind shift moves through the
northern portions of the region after Midnight. Wednesday looks to
be hot, along with thunderstorms. On Thursday, the upper level
ridge breaks down, resulting in higher wind speeds. There is the
potential that some fire weather highlights might be needed for
portions of the region later this week. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  82  54  89 /   0   0  10  10
CTB  54  76  53  82 /   0  10  30  10
HLN  61  89  58  95 /  20  10  10   0
BZN  57  88  52  94 /  40  20  10  10
WYS  48  75  41  84 /  40  60  20  10
DLN  57  87  51  91 /  40  30   0   0
HVR  57  84  56  85 /  10  10  30  30
LWT  58  82  55  85 /  20  20  10  30

&&

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

&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Jul 4, 5:43 PM MDT, 51 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
543 PM MDT SUN JUL 4 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0538 PM     TSTM WND GST     4 S BOZEMAN             45.63N 111.05W
07/04/2021  M49 MPH          GALLATIN           MT   TRAINED SPOTTER

&&

SAC

Local storm report, Jul 4, 5:44 PM MDT, 50 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
544 PM MDT SUN JUL 4 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0520 PM     TSTM WND GST     3 NNE MONARCH           47.14N 110.82W
07/04/2021  M52 MPH          CASCADE            MT   DEPT OF HIGHWAYS

            GUST FROM DECAYING THUNDERSTORM.

&&

SAC

Special weather statement, Jul 4, 5:48 PM MDT, 46 minutes before

Special Weather Statement
National Weather Service Great Falls MT
548 PM MDT Sun Jul 4 2021

MTZ015-052>055-050030-
Broadwater-Madison-Jefferson-Gallatin-Meagher-
548 PM MDT Sun Jul 4 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHERN BROADWATER...
SOUTHEASTERN MEAGHER...NORTHEASTERN MADISON...SOUTHEASTERN JEFFERSON
AND GALLATIN COUNTIES...

At 547 PM MDT, radar indicated strong thunderstorms were located
along a line extending from 20 miles east of White Sulphur Springs to
13 miles south of Ennis. Movement was southeast at 20 mph.

Wind gusts up to 50 mph and frequent lightning are possible with
these storms.

Locations impacted include...
Bozeman, Virginia City, Belgrade, Three Forks, Manhattan, Ennis,
Pony, Harrison, Big Sky, Cameron, Missouri Headwaters State Park,
Maudlow, Four Corners, Amsterdam, Jeffers, Trident, Checkerboard,
Madison Buffalo Jump State Park, Norris and Mcallister.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

LAT...LON 4541 11212 4583 11199 4666 11053 4652 11027
      4619 11028 4619 11078 4560 11080 4559 11086
      4553 11086 4552 11092 4535 11092 4535 11104
      4520 11104 4482 11135
TIME...MOT...LOC 2347Z 315DEG 15KT 4651 11048 4515 11169

RCG

Local storm report, Jul 4, 6:12 PM MDT, 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
612 PM MDT SUN JUL 4 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0515 PM     TSTM WND GST     3 SE VIRGINIA CITY      45.27N 111.88W
07/04/2021  M46 MPH          MADISON            MT   MESONET

&&

SAC

Local storm report, Jul 4, 6:15 PM MDT, 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
615 PM MDT SUN JUL 4 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0542 PM     TSTM WND GST     4 NNE MCALLISTER        45.50N 111.70W
07/04/2021  M43 MPH          MADISON            MT   DEPT OF HIGHWAYS

            NORRIS HILL MDT SITE.

&&

SAC

Special weather statement, Jul 4, 6:34 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Great Falls MT
634 PM MDT Sun Jul 4 2021

MTZ055-050100-
Gallatin MT-
634 PM MDT Sun Jul 4 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL GALLATIN COUNTY
UNTIL 700 PM MDT...

At 633 PM MDT, Doppler radar was tracking a strong thunderstorm 19
miles south of Bozeman, moving southeast at 40 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

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

This storm will remain over mainly rural areas of east central
Gallatin County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

&&

LAT...LON 4535 11112 4553 11103 4550 11092 4536 11092
      4535 11093 4535 11104 4533 11105
TIME...MOT...LOC 0033Z 293DEG 27KT 4541 11096

RCG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 4, 6:26 PM MDT	Severe Thunderstorm Warning	TFX	Gallatin, Madison	19 min
Jul 4, 6:44 PM MDT	Severe Thunderstorm Warning	TFX	Gallatin	16 min
Jul 4, 6:48 PM MDT	Special Weather Statement	TFX	Judith Basin	27 min
Jul 4, 7:01 PM MDT	Special Weather Statement	TFX	Gallatin	44 min
Jul 4, 7:13 PM MDT	Special Weather Statement	TFX	Judith Basin	32 min
Jul 4, 7:24 PM MDT	Special Weather Statement	TFX	Fergus	36 min
Jul 4, 7:56 PM MDT	Special Weather Statement	TFX	Fergus	34 min
Jul 4, 8:28 PM MDT	Special Weather Statement	TFX	Fergus	32 min
Jul 4, 9:29 PM MDT	Special Weather Statement	TFX	Meagher	31 min
Jul 5, 2:59 PM MDT	Special Weather Statement	TFX	Jefferson	31 min
Jul 5, 3:31 PM MDT	Special Weather Statement	TFX	Jefferson	29 min
Jul 5, 4:27 PM MDT	Special Weather Statement	TFX	Jefferson	33 min
Jul 5, 5:06 PM MDT	Special Weather Statement	TFX	Silver Bow	24 min
Jul 5, 5:10 PM MDT	Special Weather Statement	TFX	Lewis and Clark	35 min
Jul 5, 5:57 PM MDT	Special Weather Statement	TFX	Madison	33 min

Nearby

Special Weather Statements in Montana, 2021 Every 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.