536
FXUS65 KTFX 021005
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
405 AM MDT Thu May 2 2024

.SYNOPSIS...
A storm system slowly tracking east along the Montana and
Saskatchewan border will bring wet snow or snow showers to much of the
region today with the most impactful snow looking to fall over the
central Montana Mountains. Temperatures rise back toward normal
Saturday as ridging builds in before another precipitation
producing system arrives late this weekend into next week.

&&

.DISCUSSION...

Low pressure at the surface roughly co-located beneath a broader mid-
upper level low centered over southern Saskatchewan will track
slowly east along the International Border today and tonight,
maintaining a moist/cyclonic northwesterly flow across the area. An
area of widespread precipitation continues to pivot across north-
central MT early this morning with an embedded disturbance and lower
level boundary supporting an area of moderate precipitation that
is expected to sag south into the MT-200/US-87 corridor from Great
Falls to Lewistown by around 6 AM. This boundary slowly continues
south, reaching the US-12 corridor from Helena to White Sulphur
Springs this afternoon before dissipating. Lower to mid level flow
turns more northwesterly behind this disturbance, shifting the
focus for ongoing widespread precipitation to the central MT
mountains and adjacent areas to the north later this afternoon
through tonight while cold/cyclonic flow and emebedded disturbances
support more showery precipitation coverage elsewhere across
north-central and central MT this afternoon into this evening.

Precipitation is primarily snow above 3500 ft with winter weather
impacts likely to be limited to areas where heavier precipitation
rates occur, especially this morning. This includes areas from
near Glacier NP, where snow has been falling through the overngiht
period, south along the Rocky Mtn Front and east across the MT-
200/US-87 corridor. Winter storm warnings and advisories are in
effect for these areas with worst road conditions likely along
US-89 NW of Browning and over Kings Hill in the Little Belts.
US-87 from Belt to Geyser will also see enhanced snowfall rates
this morning with potential for a greater buildup of slush on
road surfaces there. One area to watch this afternoon will be
Lewis and Clark County where hi-resolution models suggest a
greater coverage of convective snow showers will develop. While
accumulations on road surfaces are less likely during peak
afternoon heating, periods of low visibility in areas of briefly
more intense snow could affect travelers there. Snow showers
gradually decrease in coverage tonight across lower elevation
areas but are likely to persist through much of the overnight
period across the Little Belts/Highwoods, Snowies and Bears Paw
mountains under continued moist NW flow.

A transient/weak upper level ridge develops Friday across the
northern Rockies and shifts east across the area Saturday for a
brief period of drier weather between the current upper level low
affecting the region and the next one moving onto the west coast
this weekend. Temperatures warm some on Friday but remain below
seasonal averages with widespread overnight low temperatures
likely to fall below freezing under lighter winds and clearing
skies Friday night before a seasonably mild and dry day on
Saturday. Multi-model ensembles are in broad agreement to take the
next next upper level low eastward into the Great Basin by Sunday
with southerly flow ahead of this feature importing warmer air
and moisture into the region on Sunday. This will bring an
increased risk for showers as well as thunderstorms from south to
north across the area Sunday afternoon and evening with confidence
in timing and additional details decreasing by early next week,
though an overall pattern featuring above average precipitation
chances is likely, especially for eastern portions of north-
central MT. Hoenisch

&&

.AVIATION...
1205 AM MDT Thu May 2 2024 (02/06Z TAF Period)

North-central Montana (KCTB, KHVR): Snow (KCTB) and rain/snow mix
(KHVR) will impact the hi-line through most of Thursday. Along the
Rocky Mountain front, including KCTB, there is a concern for blowing
snow this morning as winds will be gusty at times. MVFR/IFR
conditions are expected to persist through most of the TAF period
with periods of LIFR conditions possible in stronger showers.

Central Montana (KGTF, KHLN, KLWT): Rain/snow will start moving into
central Montana by 02/06Z. VFR/MVFR is expected to prevail at KGTF
and KHLN with periods of IFR possible during the day. Mountain
obscuration around KHLN will be possible after 02/14Z. KLWT will
start off the TAF period at VFR but deteriorate to IFR/LIFR by
06/12Z with blowing snow possible at times. Conditions are expected
to improve to MVFR at KLWT by 03/02Z.

Southwest Montana (KEKS, KBZN, KWYS): Showers will generally be
confined to the higher elevations of southwestern Montana with
mountain obscuration possible after 02/18Z. VFR conditions will
prevail at southwest Montana terminals with periods of MVFR/high-IFR
possible at KBZN and KWYS as some of the nearby showers may reach
lower elevations at times. Otherwise, significant impacts are not
expected through the TAF period.

Equipment Note: As of 01/18Z, the KWYS TAF has returned to service
for the summer. However, due to an inoperable ceilometer,
amendments are not scheduled until further notice.

-thor

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  40  30  50  26 / 100  70  40   0
CTB  39  29  51  26 /  90  50  10   0
HLN  50  32  57  31 /  80  50  20   0
BZN  50  26  53  28 /  40  30  10   0
WYS  44  19  48  20 /  30  40  10   0
DLN  51  28  55  30 /  10  30   0   0
HVR  43  29  51  27 / 100  50  30   0
LWT  36  26  44  23 / 100  70  50   0

&&

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

Winter Weather Advisory until noon MDT today for Cascade County
below 5000ft-Judith Basin County and Judith Gap-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 this evening for Little Belt
and Highwood Mountains.

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

&&

$$

http://www.weather.gov/greatfalls