579
FXUS65 KTFX 020254
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
854 PM MDT Wed May 1 2024



.SYNOPSIS...
A spring system will bring a mix of rain and snow showers to the
region this afternoon before transitioning to mostly snow this
evening and tonight. Impactful snow looks to fall near terrain
across Central and North-central Montana with this system through
Thursday. Temperatures rise back toward normal Saturday as ridging
builds in before another precipitation producing system arrives late
weekend into next week.

&&

.UPDATE...

Precipitation has begun to become more widespread along the Rocky
Mountain Front and Central Montana, as an upper level front
pushes south. Current webcams show some rain/snow showers falling
across the CWA, with snow mainly sticking to grassy surfaces. Widespread
rain/snow continues overnight and into the morning hours. The
heaviest snowfall remains in the Northern Rockies and Little
Belts. Traveling there will be difficult with slick roadways and
greatly reduced visibility with heavy snow. Lower elevations may
see some light snow overnight, however it will mainly accumulate
on grassy surfaces. Areas where road temperatures drop close to
freezing temperatures overnight and in the morning may develop
some lighter slushy accumulations. -Wilson

&&

.AVIATION...
600 PM MDT Wed May 1 2024 (02/00Z TAF Period)

Rain and snow showers will affect much of the northern two thirds of
the CWA tonight into Thursday. Any thunderstorms should diminish by
02z. The snow will become a bit more widespread over North Central
MT after 09z, with the snow continuing through Thursday morning. The
precipitation becomes more scattered on Thursday afternoon. MVFR to
at times IFR conditions are possible in/near heavier snow showers.
Mountains/passes will be obscured at times through the period. Brusda

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

&&

.PREV DISCUSSION...
/ISSUED 600 PM MDT Wed May 1 2024/
Through Friday morning...A large cyclonic circulation is in place
aloft across the Northern Rockies, extending out toward the Canadian
Prairies. Given the main circulation center is off to the east, a
cool northwesterly flow aloft is in place. Daytime heating today has
combined with cool temperatures aloft to result in numerous showers
across the region. A mix of rain and snow has been observed in these
showers so far, with that trend forecast to continue through the
early evening. Additionally, a few pockets of lightning have been
observed so far this afternoon in the most intense showers. Isolated
pockets of thunder will remain possible through evening. An embedded
wave within this cyclonic flow aloft will drop south from Canada
this evening, allowing for snow to become more widespread, primarily
across North-central and Central Montana tonight into Thursday. The
greatest impacts from snow with this system look to be along the
Northern Rocky Mountain Front as well as in the Little Belts. The
chance for intermittent snowfall rates in excess of an inch per hour
across Kings Hill Pass late tonight into Thursday is around 60% and
is around 30% along US-89 north of East Glacier Park.

The only change to Winter Storm Warnings and Winter Weather
Advisories was to add lower elevations of Cascade county and Judith
Basin county to an advisory tonight into Thursday morning. Most
impacts in there areas look to be confined in the Belt to Geyser
corridor late tonight into tomorrow morning. The chance for
visibility to drop to a quarter mile or less from snow in these
areas late tonight into Thursday morning is around 60% or so any
given hour. Additionally, surface temperatures look to cool enough
to support accumulating snow on roads in these areas, though that
window is rather narrow (Perhaps around midnight or so until 9 AM
Thursday).

Impactful snow largely tapers off Thursday afternoon, though light
snow will remain in pockets into Thursday night/Friday morning.

Friday afternoon into early Sunday... Transient ridging will
build into the area Friday afternoon. The result will be for a
pleasant Friday evening and Saturday, with daytime temperatures
Saturday rising to around average for early May. Warm
temperatures persist into Sunday, but precipitation chances will
begin to creep in, especially across Southwest Montana, as early
as Saturday night ahead of the next system.

Late Sunday into early next week... Transient upper level ridging
will be short lived, with another upper level disturbance dropping
SE from the Pacific NW toward the Great Basin. This system looks to
be a bit warmer in nature compared to the one passing across the
region over the net day or so, with snow looking to mostly remain in
the mountains. Overall, the chance for a quarter inch worth of
precipitation between Sunday and Wednesday is roughly around 50% at
lower elevations. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  33  40  31  50 /  80 100  60  40
CTB  32  40  29  51 / 100  80  30  20
HLN  35  49  32  57 /  40  70  30  20
BZN  24  48  27  54 /  20  40  30  20
WYS  16  43  19  48 /  20  30  20  20
DLN  24  49  27  55 /  10  10  10  10
HVR  32  45  30  51 /  80  90  50  30
LWT  29  37  27  44 /  70  90  50  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon MDT Thursday for East Glacier
Park Region.

Winter Weather Advisory until noon MDT Thursday for Northern
High Plains-Southern Rocky Mountain Front.

Winter Weather Advisory until 6 AM MDT Friday for Bears Paw
Mountains and Southern Blaine.

Winter Storm Warning until 6 PM MDT Thursday for Little Belt and
Highwood Mountains.

Winter Weather Advisory until 6 PM MDT Thursday for Big Belt,
Bridger and Castle Mountains-Snowy and Judith Mountains.

Winter Weather Advisory until noon MDT Thursday for Cascade
County below 5000ft-Judith Basin County and Judith Gap.

&&

$$

http://www.weather.gov/greatfalls