812
FXUS65 KTFX 080223
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
823 PM MDT Tue May 7 2024

.UPDATE...

The only tweak with the evening update was to increase snow
amounts in the Belt to Geyser corridor as well as in the
Lewistown areas tonight. Localized snow amounts in these areas may
exceed 6 inches in total, but given the limited spatial extent of
this amount of snow, I opted to hold off from any upgrades at this
time. Forecast guidance continues to advertise periods of snow
mixing in at Great Falls late tonight as snow levels briefly lower
to around ground level in northern Cascade County. High
resolution models only favor snow as the dominant precipitation
type in town for a few hours late tonight, with snow levels
beginning to rise later tonight as warmer air aloft begins to
nudge in from the northeast. For that reason I have held off from
increasing snow amounts around Great Falls to more than a couple
inches, but it will bear monitoring through the night for any
tweaks to the forecast.

Guidance continues to support a stripe of stronger winds aloft being
mixed to the surface with precip across the plains and adjacent
areas overnight, so the High Wind Warnings will continue as
planned.

Minor flooding has been reported in and around the Bears Paw and
adjacent areas, where an areal flood advisory remains in effect
into tomorrow. -AM


&&

.SYNOPSIS...
Widespread rain and snow will affect North Central MT through
Wednesday, along with strong winds. Over Southwest MT, expect the
precipitation to be more scattered. Temperatures remain below
normal for the next few days, but do climb back up above normal
over the weekend and into early next week, along with drier
conditions.

&&


.AVIATION...
519 PM MDT Tuesday May 7 2024 (08/00Z TAF Period)

Low clouds, rain and snow, and gusty winds will all be a concern
this TAF period, mainly across Central and North-central Montana
through the day Wednesday. Snow looks to mix in at times at lower
elevations, with prevailing snow groups included where confidence
was highest. Expect mountain obscuration through the TAF period. -AM

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

&&

.HYDROLOGY...
Heavy rainfall in the Bears Paw mountains will result in minor
flooding on Beaver Creek and possibly Clear Creek. Flood
highlights are in effect for portions of North Central MT. Brusda

&&

.PREV DISCUSSION...
/ISSUED 519 PM MDT Tue May 7 2024/
Key Points...Adjustments made to the high wind warning. Flood
statements issued, but no changes to the winter weather
statements.

Tonight through Wednesday...Rain, heavy at times will affect
North Central MT through Wednesday. There is an 80 percent chance
of 1 inch of rainfall over much of North Central MT, with a 40
percent chance for 2 inches of liquid. One concern is how low
will snow levels get. Snow levels are currently falling down to
about 4000 feet, with the possibility of snow levels falling down
to about 3500 feet. Thus snow is possible for the Great Falls
area, while periods of snow fall around Belt, Geyser and
Lewistown. With temperatures near freezing though, the snow will
melt a bit at the lower elevations, limiting snow accumulations.
However, some periods of heavier snowfall are possible at lower
elevations, which will reduce visibility. In the mountains for
elevations above 5000 feet, 6 to 12 inches of snowfall will be
common, with 1 to 2 feet in the Kings Hill and Big Snowy areas.
With a strong area of low pressure to our east, strong northwest
winds will continue. Blizzard conditions are likely tonight and
into Wednesday in the Kings Hill area. Elsewhere, the high wind
warning was expanded along the I-15 corridor from Great Falls to
Conrad as a period of strong winds are expected from now through
late tonight. Below normal temperatures are expected through
Wednesday as well.

Thursday through Tuesday...The main storm system moves off to the
east on Thursday, resulting in drier and warmer air moving in from
the west. Expect a warming trend to begin on Friday and then
continue through the weekend and into next week. Afternoon
temperatures will be around 10 to 15 degrees above normal at times
during this period. Weak upper level disturbances will try to move
southeast from Canada into the northeast portions of the CWA by
early next week. This could result in a few scattered showers or a
thunderstorm, however much of the area will likely remain dry.
Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  31  43  38  58 / 100  90  80  30
CTB  32  44  32  61 / 100  90  20   0
HLN  34  46  40  62 / 100  90  70  20
BZN  32  46  34  57 / 100  90  90  30
WYS  26  46  29  55 /  90  80  40  10
DLN  33  48  37  58 /  80 100  50  10
HVR  38  57  40  65 / 100  90  50  20
LWT  29  41  35  50 / 100  90  90  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 6 AM MDT Wednesday for Bears Paw
Mountains and Southern Blaine-Cascade County below 5000ft-
Eastern Glacier, Western Toole, and Central Pondera-Eastern
Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus
County below 4500ft-Hill County-Judith Basin County and Judith
Gap-Northern Blaine County-Snowy and Judith Mountains-Western
and Central Chouteau County.

Winter Storm Warning until midnight MDT Wednesday night for Big
Belt, Bridger and Castle Mountains-East Glacier Park Region-
Gallatin and Madison County Mountains and Centennial Mountains-
Snowy and Judith Mountains-Southern Rocky Mountain Front.

Winter Weather Advisory until 6 AM MDT Wednesday for Bears Paw
Mountains and Southern Blaine-Eastern Toole and Liberty.

Blizzard Warning until midnight MDT Wednesday night for Little
Belt and Highwood Mountains.

Winter Weather Advisory until noon MDT Wednesday for Cascade
County below 5000ft-Fergus County below 4500ft-Judith Basin
County and Judith Gap.

Winter Weather Advisory until midnight MDT Wednesday night for
Elkhorn and Boulder Mountains-Upper Blackfoot and MacDonald Pass.

High Wind Warning until midnight MDT tonight for Big Belt,
Bridger and Castle Mountains-Meagher County Valleys.

&&

$$

http://www.weather.gov/greatfalls