115
FXUS65 KBYZ 162135
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
335 PM MDT Sun Jun 16 2024

.DISCUSSION...

Through Tuesday Night...

Breezy west to northwest winds are beginning to decrease and turn
more north to northeast this afternoon as an upper low crosses
southern Canada and an associated cold front approaches. A weak
shortwave will lift north and east through Wyoming tonight
bringing isolated to scattered showers over portions of southeast
MT (15-30%). Precipitation chances begin to increase overnight
over the west as an upper trough and associated low approach the
region. Shower and thunderstorm chances will increase from west to
east on Monday (30-90%, highest west), as the aforementioned
trough moves into the region. Central and eastern areas will
likely remain dry for most of the day Monday, before easterly flow
and instability working into the region begin generating showers
and thunderstorms over these areas in the afternoon. MUCAPE
values climb up to 1000-2000 J/kg in the afternoon with deep layer
shear of 40-60 kts during the afternoon over southeast MT. SPC
currently has a Marginal risk for severe thunderstorms for these
areas on Monday, with hail and wind the main threats. Periods of
showers and thunderstorms are progged through Tuesday as the low
lifts north and east through Montana. Uncertainty still exists
with the track of the low, with some guidance taking a more
northerly track and others bringing the low across southern MT. A
northerly track would likely mean less precipitation and warmer
temperatures, so this is something to continue to watch. Have
continued with an ensemble approach to precipitation amounts.
Showers will decrease by Tuesday evening as the system lifts out
of the area. At this time, much of the area will see between 0.25
to 1 inch of precipitation (rainfall and melted snowfall) through
Tuesday. Locally higher totals are possible in the western
mountains and with thunderstorms. Latest NBM probabilities for
0.25 inches or more range from 80% or greater in the north to
40-60% in the south outside of the mountains. The probability of
0.50 inches or more range from 30-70%, highest in the west and the
north.

Cooler temperatures will move into the area as the system lifts
into the region, and snow levels will fall down to near 7000 feet
by Monday night. Several inches of snowfall are possible in the
mountains, including over the Beartooth Highway. Currently up to 4
inches of snowfall are forecast for the highway starting Monday
afternoon, and continuing at times through Tuesday. We have gone
ahead and issued a Winter Weather Advisory for the Beartooth
Highway from Monday afternoon through Tuesday with this forecast
package. Monitor the forecast and prepare for wintry conditions if
you are planning to recreate in the high country.

Temperatures are forecast to range from the 50s to the 70s on
Monday, warmest over the southeast, cooling into the 50s and lower
60s across the area on Tuesday. Low temperatures will range from
the lower 40s to lower 50s tonight, to the upper 30s to 40s on
Monday night. Tuesday night looks to be the coldest with lows in
the middle 30s to lower 40s for most locations, lowest over the
west. STP

Wednesday through Sunday...

Wednesday and Thursday look to be mostly dry with warming temperatures
as the trough starts to lift and a surface high to our east
brings southerly winds and warm air advection. WPC clusters are in
good agreement that Friday will seeing troughing return to the
region. This will create a low pressure system over the northern
plains with easterly winds advecting in plains moisture bringing
precipitation chances back to the region. There is currently a lot
of uncertainty with the deterministic models as to what this
system will look like which is to be expected 5 days out. Overall,
with the 12z runs, there seems to be a trend to lower
precipitation amounts due to high pressure in the Canadian prairie
limiting the northern extent of the low. The 12z ensembles
don`t shown a similar decrease in precipitation but this will be
something to watch over the next few days.

For the weekend, ensembles are showing shortwave ridging coming
in raising temperatures into the 80s and possibly 90s with dry
conditions. Torgerson

&&

.AVIATION...

Winds will continue to decrease for most areas during the
overnight tonight. Tonight there could be isolated (20%) showers
across the region. Tomorrow around 15Z showers will start to make
their way into KLVM and K1KM with showers becoming more
widespread across southeast Montana by 21Z. There could be some
stronger storms mixed in with these producing small hail and 50kt
winds. Torgerson

&&

.PRELIMINARY POINT TEMP/POPS...

    Mon     Tue     Wed     Thu     Fri     Sat     Sun
-----------------------------------------------------------
BIL 051/066 045/061 042/073 049/080 057/078 057/080 056/086
    14/W    76/T    11/U    01/B    25/T    43/T    11/U
LVM 043/058 037/059 034/070 041/076 048/077 050/081 050/086
    29/T    98/T    22/T    11/B    15/T    43/T    11/U
HDN 049/069 044/062 038/076 048/083 056/079 055/081 053/087
    25/T    86/T    11/U    12/T    35/T    54/T    21/U
MLS 052/068 047/060 042/073 050/080 057/078 057/078 055/084
    27/T    96/W    21/U    12/T    44/T    64/T    21/U
4BQ 052/072 048/061 042/072 051/079 058/079 058/080 055/084
    25/T    93/W    12/T    22/T    45/T    54/T    21/U
BHK 048/070 047/060 040/073 047/078 055/076 055/077 051/081
    23/T    94/W    11/B    12/T    44/T    54/T    21/U
SHR 044/075 040/061 037/073 046/080 054/079 053/080 052/086
    25/T    74/T    12/T    11/B    45/T    54/T    21/U

&&

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

&&

$$
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