000
FXUS65 KTFX 160043
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
643 PM MDT Mon Apr 15 2024

.SYNOPSIS...

Rain showers across southwest Montana and parts of Central Montana
continue this afternoon and evening. Near normal afternoon high
temperatures (cooler in the mountains) tomorrow then colder
temperatures for the rest of the work week. Gusty winds tomorrow and
snow begins for southwest Montana mountains and along the Rocky
Mountain Front moving southeast across the area Tuesday night into
Wednesday.

&&

.UPDATE...

Updates were made to the precip chances in the first 6 hours to
better match recent radar trends and updated model guidance.
Scattered showers with some isolated thunderstorms will continue
to impact the region before tapering off after sunset. Otherwise,
no changes to the going forecast.

-thor

&&

.AVIATION...
640 AM MDT Mon Apr 15 2024 (16/00Z TAF Period)

Some scattered showers and isolated thunderstorms are possible
near KGTF, KHVR, and KLWT over the next couple hours before
tapering off. There have been some isolated showers in southwest
Montana but I did not have high enough confidence to add it to
either the KBZN or KEKS TAFs. The main concern with these showers
will be lightning and gusty erratic winds with any developed
thunderstorms

Otherwise, VFR conditions are forecasted to prevail for all sites
through the TAF period with some temporary reductions to MVFR/IFR
possible for KBZN, KEKS, KCTB after 16/21Z due to incoming rain
and snow showers. The end of the TAF period will see the start of
the next system expected to move through the region which starts
Tuesday afternoon and will last through Wednesday night.

-thor

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

&&

.PREV DISCUSSION...
/ISSUED 252 PM MDT Mon Apr 15 2024/

Rest of today through tomorrow night... A closed upper level low
over southwest U.S. is bringing unsettled weather conditions for
Southwest and parts of Central Montana today and tonight. Rain
showers should continue into the early evening hours, with a
potential (50%) of a non-severe thunderstorm this evening with
primary concern being a heavy downpour, lightning, and gusty winds
up to 30 mph. Westerly winds across the Rocky Mountain Front and the
adjacent Hi-Plains region continue to gust between 25 and 35 mph
through this evening. After tonight, there`s a break in the
precipitation until tomorrow night when our next weather system
moves in from Canada bringing mountain snowfall Tuesday night into
Wednesday morning along the Rocky Mountain Front. The Madison
Range mountains in Southwest Montana could see about the same
onset timing of snowfall beginning Tuesday night and continuing
into Wednesday morning. Precipitation moves southeast into the
Little Belt Mountains and Central Montana overnight Tuesday into
the early morning hours of Wednesday.

Wednesday through Friday... Latest National Blend of Models (NBM)
4.1 data suggests 24 hour snowfall probabilities of greater than
2 inches of snow is above 75 percent for the mountainous terrain
of the Rocky Mountain Front to the Little Belt Mountains and
Madison Range Mountains. For Great Falls and Lewistown, the
probabilities are less than 30 percent for snowfall amounts
greater than 2 inches for Wednesday morning into Thursday morning.
Precipitation becomes more confined to lingering mountain
snowfall for Wednesday evening through Friday. Winter weather
highlights remain for this timeframe for locations to see the most
impacts, such as mountainous terrain, of winter weather (example
includes snowfall amounts). Temperatures remain well below normal
for this time of year, with highs in the 30s for Wednesday through
Friday and overnight low temperatures in the teens (with single
digits in the mountains).

Saturday through Monday... A return to near normal afternoon high
temperatures in the 50s and 60s is in the forecast for this upcoming
weekend into early next week with ensemble model guidance in support
for upper level ridging to return to the area. Dry conditions are
favored by the latest model guidance during this time period. Webb

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  68  39  53  29 /  20  10  10  80
CTB  65  36  47  25 /   0   0  50  60
HLN  68  39  55  31 /  20  10  10  70
BZN  64  33  57  27 /  80  20  40  80
WYS  55  26  47  23 /  70  30  40  80
DLN  60  32  56  27 /  40  10  20  60
HVR  72  42  55  29 /  10  10  20  30
LWT  62  37  53  26 /  70  10  10  60

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from noon Tuesday to 6 AM MDT Wednesday
for East Glacier Park Region-Northern High Plains.

Winter Weather Advisory from 9 PM Tuesday to noon MDT Wednesday
for Big Belt, Bridger and Castle Mountains-Gates of the
Mountains-Little Belt and Highwood Mountains-Southern High
Plains-Southern Rocky Mountain Front-Upper Blackfoot and
MacDonald Pass.

Winter Storm Warning from 6 PM Tuesday to 6 PM MDT Wednesday for
Gallatin and Madison County Mountains and Centennial Mountains.

&&

$$

http://www.weather.gov/greatfalls