Winter Storm in Montana, March 4, 2018

Name: Winter Storm in Montana, March 4, 2018
Start: 2018-03-04T12:45
End: 2018-03-04T19:55
Location: Montana

March 4, 2018 · NWS TFX · 4 events in 4 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS TFX wrote it up.

An upper-level shortwave trough moved from the Pacific Northwest and northern California to central Montana and western Wyoming from the early evening of March 3rd through late evening of March 4th. At 700 mb, a low- to mid-level shortwave trough shifted from Idaho and vicinity to eastern Montana. Simultaneously, a low pressure center developed within this shortwave. Horizontal wind shear associated with the counter-clockwise, inward circulation of this low led to weak 850-700 mb frontogenesis and associated ascent over North-Central and Southwest Montana. Large-scale ascent associated with the aforementioned frontogenesis and upper-level divergence ahead of the shortwave trough, combined with sufficient moisture, led to the development of snow over the region. At the surface, a front meandered near the Rocky Mountain Front and the mountains near Great Falls. This front separated cold air to its north from relatively-milder air to its south. This system delivered significant snow amounts to portions of North-Central and Southwest Montana, while the heaviest snow was focused east of I-15. While snow fell March 3rd through 5th, the bulk of accumulation occurred on the 3rd and 4th. In addition, Great Falls set a new snowfall record for March 4th (5.1 inches). The previous record was 4.0 inches set in 1918.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Mar 4, 11:00 AM MST, 1 hour 45 minutes earlier.

Area forecast discussion, Mar 4, 11:00 AM MST, 1 hour 45 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
1100 AM MST Sun Mar 4 2018

Aviation Section Updated.

.UPDATE...

We are observing peak snowfall rates across central and southwest
MT this morning associated with the developing winter storm
system. Southerly flow aloft is pushing moisture up and over a
deepening cold air layer that is advancing from the north. The
upper level trough axis is progressing quickly over the area. We
expect snowfall rates will decline from southwest to northeast
through early afternoon as the trough axis aloft moves east of our
forecast area. The forecast was adjusted slightly to better match
observed trends, but otherwise remains in pretty good shape. PN

&&

.SYNOPSIS...
An upper level disturbance will bring widespread snow across the
region today. Areas along Interstate 15 and eastward will see
moderate to heavy snow at times...especially this morning. Snow
then becomes more scattered tonight as the disturbance exits the
region. Temperatures will be colder today, with highs only in the
20s and lows in the single digits to teens tonight.

&&

.AVIATION...
Updated 1800Z.

LIFR to VLIFR conditions are occurring in moderate snow at central
MT terminals late this morning. Expect conditions to gradually
improve through mid afternoon as a strong winter storm begins to
move away into eastern Montana. Snow will end tonight...although
lingering low clouds and possible return of fog could bring more
MVFR to IFR conditions through the night. Mountain obscuration is
expected throughout the period. Increased icing threat is also
possible in snow and areas of freezing fog. PN

&&

.PREV DISCUSSION...
/ISSUED 514 AM MST Sun Mar 4 2018/

Today through Tuesday...Large upper level low will bring
widespread snow and cooler temperatures today...with diminishing
chances and slightly below normal temperatures Monday through
Tuesday. Upper level low appears to be taking the more westerly
track as has been monitored the last couple of days. This means
that a shot of moderate to heavy snow will be found along and east
of I-15 and south of US 2 this morning. A decent dendritic growth
layer could also enhance snowfall rates this morning. Most
highlights remain the same with Warnings now across central
and southwest portions of MT and advisories for most other areas
except along much of the Hi-Line. There was some consideration
given to expanding the warning westward into Cascade and Choteau
counties given latest radar trends. Although moderate to heavy
snow is possible for these areas...feel the impacts will only be
limited to the morning hours. Will continue to monitor these and all
areas for potential upgrades. Overall 2 to 4 inches of new snow are
possible, with higher amounts of 4 to 8 inches possible across
central and southwestern portions. Temperatures today will return
to more winter like readings...with highs only in the 20s. Snow
diminishes fairly quickly tonight as the low move eastward into
the Dakotas. Behind it will be cool temperatures, especially for
any areas that can have a bit of clearing. Monday and Tuesday we
then see northwest flow set up across the region. Monday's nw flow
may have a bit of instability with it...lingering chances for
scattered snow showers. Tuesday could also see some isolated snow
showers...although instability is not as high. Temperatures for
Monday and Tuesday will be warmer than today...but still below
normal with highs in the 30s and morning lows in the single digits
or teens. A few other items of interest...fog threat remains
across northwest portions early this morning. Once snow begins to
pick up...fog threat should diminish. Some increased wind gusts
across the east could also bring a blowing snow threat today. This
threat was included in the current Winter Storm Warning. Anglin

Tuesday night through Sunday...A relatively quiet period of
weather is anticipated Tuesday night through Wednesday night as an
upper level ridge progresses east across the Northern Rockies and
MT. The upper ridge flattens in response to incoming energy from
the eastern/NE Pacific Thursday and Friday with typical spread
among medium range models at this time range regarding the details
of the passage of a weakening Pacific upper trough across the
region Friday/Friday night. This would bring increasing winds to
western portions of north-central MT Thursday and Friday as a lee-
side surface trough develops in response to increasing westerly
flow aloft. Precipitation chances increase late this week,
primarily over the mountains with lesser chances further east.
Temperatures initially below seasonal averages should warm to near
or even slightly above seasonal averages late this week into the
weekend as westerly flow from the Pacific spreads across the
region with longer range models hinting at a more robust upper
ridge potentially building across the western US next weekend.
Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  20   6  30   9 / 100  50  20  20
CTB  17  -3  27   6 /  30  20  20  20
HLN  22  10  33  15 / 100  40  20  20
BZN  27   8  31   9 / 100  60  20  20
WEY  23   1  22   4 /  80  30  30  30
DLN  24  10  28   5 / 100  30  20  10
HVR  22   2  19   2 /  90  80  10  10
LWT  20  11  29  10 / 100  90  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM MST this afternoon below 6000
feet for Gallatin...Madison.

Winter Storm Warning until 5 PM MST this afternoon above 6000
feet for Gallatin...Madison.

Winter Weather Advisory until 5 PM MST this afternoon
Broadwater...Central and Southern Lewis and Clark...Jefferson...
Meagher.

Winter Storm Warning until 11 PM MST this evening Blaine...
Fergus...Judith Basin.

Winter Weather Advisory until 5 PM MST this afternoon Cascade...
Chouteau.

Winter Weather Advisory until 5 PM MST this afternoon Hill.

Winter Weather Advisory until 5 PM MST this afternoon Beaverhead.

&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Mar 4, 11:39 AM MST, 1 hour 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1139 AM MST SUN MAR 4 2018

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

1100 AM     SNOW             1 ESE GREAT FALLS       47.50N 111.27W
03/04/2018  M5.7 INCH        CASCADE            MT   NWS EMPLOYEE

            5.7 INCHES OF NEW SNOW.

&&

BRUSDA

Local storm report, Mar 4, 11:43 AM MST, 1 hour 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1143 AM MST SUN MAR 4 2018

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

1130 AM     SNOW             3 WNW MONTANA CITY      46.55N 112.00W
03/04/2018  M2.5 INCH        JEFFERSON          MT   TRAINED SPOTTER

            2.5 INCHES OF NEW SNOW SINCE 530 AM.

&&

BRUSDA

Local storm report, Mar 4, 11:47 AM MST, 58 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1147 AM MST SUN MAR 4 2018

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

1130 AM     SNOW             1 NNW CANYON CREEK      46.82N 112.27W
03/04/2018  M4.0 INCH        LEWIS AND CLARK    MT   TRAINED SPOTTER

&&

BRUSDA

Local storm report, Mar 4, 11:50 AM MST, 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1150 AM MST SUN MAR 4 2018

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

1149 AM     SNOW             6 NNE CASCADE           47.35N 111.63W
03/04/2018  E2.0 INCH        CASCADE            MT   PUBLIC

&&

BRUSDA

Local storm report, Mar 4, 12:13 PM MST, 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1213 PM MST SUN MAR 4 2018

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

1200 PM     SNOW             CHURCH HILL             45.75N 111.30W
03/04/2018  M4.5 INCH        GALLATIN           MT   PUBLIC

            4.5 INCHES OF NEW SNOW IN THE PAST 24 HOURS.

&&

BRUSDA

Local storm report, Mar 4, 12:24 PM MST, 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1224 PM MST SUN MAR 4 2018

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

1200 PM     SNOW             1 NNW LEWISTOWN         47.07N 109.43W
03/04/2018  E3.3 INCH        FERGUS             MT   TRAINED SPOTTER

            STORM TOTAL OF 3.3 INCHES SO FAR.

&&

BRUSDA

Event by event

4 winter storm. Local standard time, as filed.

Winter Storm, Fergus

When: March 4, 12:45 PM MST
Where: Fergus forecast zone
Reported by: Department of Highways

US-191 closed from Eddie's Corner to junction with US-12 near Harlowton.

Winter Storm, Judith Basin

When: March 4, 12:45 PM MST
Where: Judith Basin forecast zone
Reported by: Department of Highways

US-191 closed from Eddie's Corner to junction with US-12 near Harlowton.

Winter Storm, Gallatin

When: March 4, 2:50 PM MST
Where: Gallatin forecast zone
Reported by: Public

Public report of 9-inches of new snow since midnight March 4th. Report location was 5-miles E of Gallatin Gateway at elevation of nearly 5335 feet MSL.

Winter Storm, Blaine

When: March 4, 7:55 PM MST
Where: Blaine forecast zone
Reported by: Department of Highways

MT-66 closed in Blaine County.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2018 Every state in 2018 This day in weather history Warnings in Montana, March 2018

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 736195, 736196, 736198, 736197.