029
FXUS65 KTFX 012048
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
248 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.

&&

.DISCUSSION...

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

&&

.AVIATION...
128 PM MDT Wed May 01 2024 (01/18Z TAF Period)

Note: The NWS Great Falls Weather Forecast Office manages the
following TAFs: KCTB, KHVR, KGTF, KLWT, KHLN, KBZN, KEKS and KWYS.

The next weather system is upon us, causing conditions at our
airfields to degrade, due to snow/rain, blowing snow or mist, and/or
low ceiling.

Throughout this TAF period, KCTB experiences MVFR/IFR conditions,
with gusty northwesterly winds. All other airfields begin this TAF
period in VFR conditions, and begin slipping into MVFR conditions,
from 01/21Z. Southwesterly to northwesterly gusty winds are
forecast, with the strongest winds along The Rocky Mountain Front,
where winds are forecast to gust up to 45KT. Across portions of
central Montana, winds are forecast to gust to 35KT and 40KT. The
strongest winds are forecast to occur during today`s afternoon and
evening hours. Mountain obscuration should be expected.
- Fogleman

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  30  40  31  50 /  80  90  60  40
CTB  30  40  29  51 /  90  80  30  20
HLN  30  49  32  57 /  50  70  30  20
BZN  23  48  27  54 /  40  40  30  20
WYS  13  43  19  48 /  40  30  20  20
DLN  24  49  27  55 /  20  10  10  10
HVR  31  45  30  51 /  80  80  50  30
LWT  28  37  27  44 /  80  80  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 from 6 PM this evening to 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 from 10 PM this evening to noon MDT
Thursday for Cascade County below 5000ft-Judith Basin County and
Judith Gap.

&&

$$

http://www.weather.gov/greatfalls