707
FXUS65 KBYZ 192048
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
248 PM MDT Sat Apr 19 2025

.KEY MESSAGES...

- Broken line of showers tonight into Sunday morning. Additional
  isolated to scattered showers Sunday afternoon through Sunday
  night. Rumble of thunder possible Sunday PM (10-20% chance).

- More persistent precipitation (mountain snow/lower elevation
  rain) on Monday (40-80%). Isolated Thunderstorms PM.

- Periods of showers Tuesday through the work week.

- Temperatures in the 45-55 degF range through Wednesday, warming
  up Thursday/Friday into the 60s.

&&

.DISCUSSION...

Through Sunday night...

The quiet and dry weather today will not hang around long as
multiple chances of precipitation return to the area forecast
beginning tonight. This is due to the progressive nature of the
upper level flow expected this week.

The first weaker shortwave will move into the region tonight,
along with its associated cold front. With this, a broken line of
precipitation will move from west to east through the region late
this evening into Sunday morning. Precipitation within this broken
line is expected to be all rain over the lower elevations and all
snow in the mountains generally above 7000 feet. Due to the
overall weak nature of this first shortwave, precipitation amounts
are expected to remain light (generally 0.10 inches or less of
liquid over the lower elevations). In the mountains, generally 1
to 2 inches of snow with locally higher amounts on west facing
slopes are forecast. Breezy northwesterly winds will also
accompany the front tonight (gusts of 15 to 25 mph).

A brief break in the precipitation will occur during the day
Sunday behind the first wave. Upper level divergence from a
digging trough over the Pacific Northwest will then allow
additional isolated to scattered showers to develop Sunday
afternoon into Sunday night over south-central Montana. With this,
the best chance of precipitation comes Sunday night into Monday
as the upper level trough approaches over region (50 to 75 percent
chance). Before this, an isolated thunderstorm is possible mainly
west of Billings Sunday afternoon and evening (10 to 20 percent
chance), but recent surface moisture will limit the usual strong
wind threat with any storm that does develop. As with the first
system, all rain is expected over the lower elevations Sunday,
with snow generally above 7000 feet. See long- term discussion for
additional precipitation chances through the week. Arends

Monday through Sunday...

Broad but not terribly deep trof arrives for Monday and lingers
into Tuesday for the area. This will bring another good chance
(50-80%) for precipitation, mainly on Monday. Tuesday will be more
instability showers with gusty northwest winds. 48 hour NBM probabilities
for more than a third of an inch are in the 60 to 80 percent
range for a broad area west of Rosebud county from Monday through
Tuesday. NBM probabilities for over half an inch show pockets of
30 to 35 percent in the same areas. There will be a chance for
isolated thunderstorms across the area Monday afternoon into
Monday evening, even in the mountains where snow is forecast.

Snow accumulations for the mountains look to stay below highlite
thresholds. NBM showing 48 hour accumulation probabilities for
over 10 inches staying below 20 percent above 7000 feet and below
40 percent for the highes peaks. Still looking at a chance for
light (T-2in) accumulations for the western foothills from Monday
morning through the evening hours. Snow on Tuesday will be more
spotty over the foothills. This time of year expect most
accumulations to occur in the overnight hours, with snow mainly
melting as it falls during the day across lower to mid elevation
locations.

By Wednesday something occurs that hasn`t really happened since
last fall, an appearance of Gulf moisture rides the low level jet
north along the front range. Low level moisture will persist over
the area through the week and into next weekend with periodic
southerly/easterly wind fields continuing to move moisture into
the area. Near saturated soil moisture will also help to keep low
level moisture in place from recent precipitation events over
central and western zones.

A weak disturbance Wednesday will bring another round of showers
to the area with the potential for a tenth of an inch of
precipitation across the area. Yet another weak disturbance will
bring a chance for showers Thursday, and then a stronger Pacific
low will begin to influence shower/thunderstorm activity from
Friday through the weekend. Will have to keep a close eye on
this stronger system for the weekend given the strong moisture
presence over the area.

Highs will be mainly in the 45 to 55 degree range until Thursday
when a slow warm up toward 60 degrees takes place. Temperatures Friday
into the weekend will depend on the timing of the Pacific system,
but should get well into the 60s Friday as southwest flow develops
ahead of the Pacific storm. Chambers

&&

.AVIATION...

Mid to high level clouds will increase from west to east this
evening. By late this evening into Sunday morning, a broken line
of precipitation (lower elevation rain and mountain snow) will
move through all TAF sites from west to east. With this, a period
of low, MVFR ceilings is possible (moderate chance). After a break
in the precipitation mid-day Sunday, additional isolated to
scattered lower elevation rain and mountain snow showers are
expected Sunday afternoon through Sunday night. A rumble of
thunder or two is possible mainly west of KBIL Sunday afternoon
and evening as well (10 to 20 percent chance). Arends

&&

.PRELIMINARY POINT TEMP/POPS...

    Sun     Mon     Tue     Wed     Thu     Fri     Sat
-----------------------------------------------------------
BIL 042/060 041/055 035/057 037/055 037/059 041/065 044/069
    54/W    69/T    42/W    24/W    33/W    23/W    33/W
LVM 036/058 036/048 027/053 032/052 034/056 036/061 041/063
    64/T    89/T    22/W    25/W    33/W    24/W    34/T
HDN 039/060 038/057 033/058 035/057 036/060 039/066 043/072
    56/W    59/T    52/W    24/W    44/W    33/W    33/W
MLS 037/058 037/058 036/056 032/057 037/058 039/064 045/068
    25/W    28/T    42/W    12/W    33/W    22/W    22/W
4BQ 032/057 036/058 037/056 034/056 037/057 041/062 046/069
    04/W    18/T    42/W    13/W    44/W    33/W    22/W
BHK 029/058 032/058 033/053 029/056 034/057 035/061 039/064
    04/W    08/T    52/W    12/W    34/W    22/W    22/W
SHR 031/054 031/054 029/055 029/054 032/056 036/064 041/069
    26/W    19/T    42/W    24/W    44/W    34/W    33/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
weather.gov/billings