000
FXUS65 KTFX 141148
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
548 AM MDT Sun Apr 14 2024

...Aviation Section Update...

.SYNOPSIS...
It will be a sunny start to the day today, however, a few showers
and thunderstorms will develop by late afternoon and slowly move
eastward across Central MT this evening. On Monday, expect similar
conditions, wit the best chance for storms around Big Sky. Mild
temperatures today and Monday will give way to much colder
temperatures by the middle of the week, along with rain changing
to snow at all elevations by Tuesday night. The cold snap will not
last long, as drier and mild conditions return by next weekend.

&&

.DISCUSSION...
Today through Monday...A southwest flow aloft will reside over
the CWA today. After a quiet morning, an upper level disturbance
is expected to move northeast through the CWA this afternoon,
producing a few late afternoon or evening showers/thunderstorms,
mostly over Central MT. A few of the storms could produce wind
gusts near 50 mph, per the HRRR between 5 PM and 9 PM this
evening. Otherwise, expect a mild afternoon, with a few locations
near record highs once again. On Monday, and upper level trof will
approach the CWA from the north, with most of the
showers/thunderstorms over the eastern portions of the CWA.
Additionally, afternoon temperatures on Monday will not be quite
as mild as they were today, and will generally average about 10
degrees cooler than they were today.

Tuesday through Thursday...A short period of winter conditions is
expected to move into the CWA on Tuesday and then continue to
reside over the CWA into Thursday. The main cold front looks to
push southward through the CWA on Tuesday. Expect gusty north
winds to develop behind the front, with Tue night into Wed likely
being the period of strongest north winds. I did increase wind
speeds a bit over the NBM during this period over North Central
MT, but did keep wind speeds below warning criteria. Rain showers
will develop ahead of the front, with snow falling behind the
front. For most elevations, the rain will change to snow by
Tuesday night. Accumulating snow is possible, mainly along and
west of a line from Cut Bank to Fort Benton to Lewistown. Much of
the northeast section of CWA, such as Havre/Harlem will just
receive a passing snow shower, with little/no accumulation. For
areas around Glacier Park, the forecast models have been fairly
consistent in showing snow accumulations of 1 to 3 inches at
lower elevations and about 4 to 8 inches in the mountains. Thus a
winter weather advisory has been issued for this area. Further
south it is looking like a winter weather advisory will be needed
for portions of Central MT, especially the mountain areas around
Kings Hill. As you move into Southwest MT, the mountains around
Pony and Big Sky continue to prog near a 70 percent chance of
snow accumulations over 8 inches. Thus a winter storm watch has
been issued for these areas. Note, snow accumulations do look
lower along the MT/ID border, including areas around West
Yellowstone. Overall, there is a 95 percent chance that much
colder air will move into the region starting Tue and then
continuing thru Thu. I did blend the NBM with some colder GFS
temperatures through this period.

Friday through Sunday...The main upper level trof will be exiting
the area on Friday, allowing for the snow to come to an end and a
warming trend to begin. It will take a few days to warm back above
normal, but that is looking likely by Sunday. Additionally, as the
upper level ridge tries to develop over the CWA next weekend, it
is looking mostly dry as well. Brusda

&&

.AVIATION...
548 AM MDT Sun Apr 14 2024 (14/12Z TAF Period)

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

VFR conditions prevail at all airfields, with the exception of KGTF
and KBZN where PROB30s are included, bringing these airfields into
MVFR conditions due to low visibility in light rain showers. The 30%
chance of MVFR conditions at KGTF is forecast to impact the
airfield, this evening, while the 30% chance of MVFR conditions is
forecast to impact KBZN, tomorrow morning. Isolated thunderstorm
activity is forecast to develop during today`s afternoon hours and
move through our region into the evening hours. Forecast winds are,
generally, light; however, during today`s afternoon and early
evening hours, southerly winds across southwest Montana, favor the
development of some gusty winds through north-south oriented
valleys. Toward the end of this TAF period, gusty winds to 35KT
develop across The Northern Rocky Mountain Front. Additionally,
gusty and erratic winds are expected near thunderstorms and rain
showers. Of course, all aviation flight hazards are assumed in and
near thunderstorm activity.
- Fogleman

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  75  45  69  40 /  10  30  20   0
CTB  72  42  64  34 /   0   0   0  10
HLN  79  46  67  38 /  20  20  20   0
BZN  76  40  64  32 /  10  20  50  20
WYS  67  30  57  25 /  10  20  60  30
DLN  71  39  60  33 /  10  10  30   0
HVR  75  44  73  40 /   0  10  10  10
LWT  73  44  64  37 /  20  20  50  10

&&

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

Winter Storm Watch from Tuesday evening through Wednesday
afternoon for Gallatin and Madison County Mountains and
Centennial Mountains.

&&

$$

http://www.weather.gov/greatfalls