928
FXUS65 KTFX 111047
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
447 AM MDT Sat May 11 2024

...Aviation Section Updated...

.SYNOPSIS...

Warm and mostly dry conditions are expected through the weekend as
upper level ridging remains over the area, with just a few light
rain showers possible along the Hi Line tonight. Cooler and
unsettled weather will return for early next week, with light rain
expected Monday evening through Tuesday.

&&

.DISCUSSION...

 Key Points:

-Warmth continues through the weekend with periods of smoke from
 Canadian Wildfires

-Cooler air arrives around midweek with a round of light rain

Short term (through Monday)... Today will start out on the warm
and dry side across North Central and Southwestern Montana as high
pressure continues to exert its influence across the area, though
clouds will continue to gradually work their way in from the
north. Under partly to mostly sunny skies today, highs will push
into the 70s and even some low 80s across the area with mostly
light winds. Clouds will thicken and give way to a few rain
showers overnight tonight along the Hi-Line as a weak weather
system moves across Southern Alberta and Saskatchewan. While rain
will be on the light side from this system, we will have to watch
for any worsening of flooding of streams and creeks coming from
the Bears Paw Mountains. Otherwise, the only other impact so to
speak will be that the clouds will pose some difficulty for those
who would try to get a second glance at the northern lights,
should the ongoing solar storm persist into the overnight hours
tonight.

Sunday and Monday will both feature a continuation of the
ongoing warmth, though we will have to watch for some smoke from
wildfires that have returned to life across British Columbia over
the past 48 hours as upper level flow tries to advect some of that
smoke towards us. Otherwise, expect clouds to build on Monday
with a few rain showers developing across Southwestern Montana as
our next weather system begins to approach. Expect rain showers to
become more widespread through the overnight hours as moisture
continues to push into the area.

Extended (Tuesday through next Saturday)... Expect periods of
rainfall to continue through the day on Tuesday as moisture
continues to work into the area from the north and west. For the
most part, precipitation will be rainfall except at the highest
elevations even as cooler air from Canada pours into the region
behind a surface cold front that will work in with the rain.

Beyond Tuesday, expect cool but dry weather through the end of the
week as an upper level ridge sets up to our south. The quiet
weather will persist into the weekend, though there will be a
chance for a system to bring some slightly unsettled weather to
the area for the weekend. Ludwig.

&&

.AVIATION...
447 AM MDT Sat May 11 2024 (11/12Z TAF Period)

VFR conditions will prevail beneath periods of upper level
cloudiness through the TAF period, with no mountain obscuration. A
weak disturbance moving over the Northern Rockies this afternoon
will bring a subtle wind shift to the northwest through the early
evening hours before winds go light and variable. Isolated to
scattered showers are possible near the KHVR terminal beyond 06z
Sunday; however, confidence in any shower impacting the terminal is
low. - Moldan

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

&&

.HYDROLOGY...
A Flood Warning remains in effect for Clear Creek in North Central
Montana through Saturday morning, with water levels expected to
slowly fall from minor flood stage to action stage over this
timeframe. Additionally, a Flood Watch remains in effect for the
nearby Bears Paw Mountains through the weekend as warming
temperatures and subsequent snowmelt runoff, and remaining runoff
from rainwater, could push creeks and streams out of their banks.
While some rainfall is expected this evening, rainfall amounts
should not be high enough to significantly worsen any flooding of
streams and creeks.

Further south across the Island Ranges of Central Montana (i.e.
Highwood, Moccasin, Judith, Little Belt, and Snowy), increased
snowmelt and subsequent runoff into creeks and streams is expected
through Monday as overnight temperatures and dewpoint temperatures
remain above freezing. This runoff could result in waterways
nearing bankful by Saturday night/Sunday morning. Hence, a Flood
Watch has been issued for the Little Belts eastward toward the
Lewistown area. - Moldan/AM/Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  78  46  79  49 /  10  10  10  10
CTB  78  44  79  48 /  10  10  10   0
HLN  80  51  81  52 /   0   0   0   0
BZN  76  43  78  45 /   0   0  10  10
WYS  68  34  70  36 /   0   0  10  10
DLN  75  42  76  46 /   0   0   0   0
HVR  80  47  77  49 /   0  40  10  30
LWT  72  45  71  48 /   0  20  30  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Sunday morning for Bears Paw Mountains and
Southern Blaine.

Flood Watch from noon MDT today through Monday morning for
Cascade County below 5000ft-Fergus County below 4500ft-Judith
Basin County and Judith Gap-Little Belt and Highwood Mountains-
Meagher County Valleys-Snowy and Judith Mountains-Western and
Central Chouteau County.

&&

$$

http://www.weather.gov/greatfalls