910
FXUS65 KBYZ 260133
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
733 PM MDT Fri Jul 25 2025

.KEY MESSAGES...

- Isolated thunderstorms this evening and again Saturday have the
  potential to produce strong/erratic wind gusts.

- Daily chance of showers and thunderstorms continue Sunday and
  much of next week. Storms will become wetter. The best potential
  for more widespread precipitation is next Tuesday through
  Thursday.

- Near normal temperatures (upper 80s to mid 90s) through the
  weekend turning slightly cooler than normal next week.

&&

.UPDATE...

Updated forecast mainly for ongoing convection. The strongest
storm this afternoon/evening was one that formed over far NE
Rosebud county and has slowly worked east-southeast through Custer
and Fallon county and is now moving into ND. Torrential rainfall,
half dollar size hail and wind gusts as high as 78 mph (Glendive
AWOS) accompanied this storm. Additional convection formed over
the southwest mountains in a much drier lower atmosphere and
mainly produced wind gusts of 35 to 50 mph, though an isolated
gust to 59 mph was recorded at the Livingston airport. Severe
storm potential will rapidly diminish over the next few hours with
models ending just about all storm threats by 10pm or so. Latest
forecast confines precipitation potential to the northern half of
the forecast area (Livingston to Billings to Ekalaka and north)
for the rest of the evening. Did elevate winds accounting for HRRR
convective gusts through the evening hours. Rest of the forecast
is in good shape. Chambers

&&

.DISCUSSION...

Through Sunday night...

A weak disturbance tracking across our east this afternoon is
progged to trigger convection just east of a surface trough this
impacting eastern Custer, Fallon and Carter Counties for the
latter part of the day into the early evening. MUCAPE ranges from
1000-1250 J/kg in our east, so despite weak effective shear
(<30kts), there is a chance of storms producing strong winds, hail
and heavy rain in these areas. In the meantime, the typical
convection is firing across the mountains in our western CWA from
differential heating, and with the usual perturbation coming out
of the high country this afternoon, we should see
isolated/scattered coverage of convection spread out into the
nearby plains later today. This activity is expected to be
somewhat high based with little chance of hail and heavy rain.
However, strong winds with stronger cells is certainly possible
with soundings indicating a notable inverted-V. CAMs indicate most
of the convective activity across our CWA will lift E/NE out of
our area by 11 pm.

Late tonight and Saturday morning will be dry, then the next
round of afternoon & evening t-storms arrives as a slightly
stronger wave lifts out of SW flow aloft. PWATs will be higher
tomorrow as low level winds turn to the east. The main risk of
storms tomorrow will again be wind, but with the greater
moisture/instability and slightly higher shear, there should be a
low risk of hail and locally moderate to heavy rain as well. The
day 2 SPC outlook also highlights our region with a marginal risk
of severe t-storms.

For Sunday...500 mb heights build a bit over our region through
Sunday evening. This pushes the more active southwest flow to our
west/northwest, but also increases the potential for some
monsoonal flow from the south under the ridging. Bottom-line, we
should remain active with at least a chance of isolated/scattered
showers and storms. Placement and intensity are uncertain...but
for now best chance of storms is across our west/northwest zones
(think Beartooths to Snowies).

Highs through the weekend will range from mid 80s west to lower
to mid 90s east. Look for lows in the mid 50s to lower 60s. BT

Monday through Friday...

An active pattern is expected for next week as shortwaves move
through upper level, westerly flow. Additionally, easterly low
level winds will advect unseasonably high moisture into the
region, which will be something to watch.

Tuesday into Thursday look to have the highest PWATs, around
130-160% of normal (1.0-1.3"). This will lead to elevated
potential for heavy rain with any showers or thunderstorms that
develop. While thunderstorms will be possible each day, CAPE
values are currently expected to be highest Tuesday and Wednesday,
with a 60-80% chance of CAPE values greater than 1000 J/kg. Stay
tuned to the forecast, especially if you have outdoor plans.

High temperatures will be in the mid 80s to low 90s Monday,
becoming very slightly cooler for the rest of the week, with highs
in the upper 70s to upper 80s. Archer
&&

.AVIATION...

Isolated showers and thunderstorms will continue through late
evening (04-05z) mainly north of a Livingston to Billings to
Ekalaka line. Precipitation will be mainly light with remaining
convection so VFR conditions should prevail, however wind gusts of
30 to 40kts will be possible near precipitation areas. Once
convection dies off late this evening, VFR conditions and light
winds will prevail into Saturday afternoon. Chambers

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 061/092 060/090 060/087 061/081 062/084 061/086 061/088
    22/T    21/U    21/U    23/T    54/T    42/T    32/T
LVM 052/089 052/088 051/086 053/081 055/082 055/085 054/087
    33/T    23/T    22/T    23/T    44/T    33/T    33/T
HDN 058/093 058/092 059/090 060/083 061/086 060/087 060/089
    22/T    21/U    11/U    23/T    54/T    42/T    32/T
MLS 063/095 063/092 064/087 063/083 063/082 061/086 063/088
    21/H    31/U    22/T    53/T    53/T    42/T    32/T
4BQ 064/093 062/091 064/091 063/081 063/079 062/083 063/086
    02/T    20/U    11/U    43/T    63/T    52/T    32/T
BHK 060/094 059/090 060/081 058/078 058/077 056/079 058/082
    31/U    41/U    22/T    63/T    43/T    42/T    32/T
SHR 058/089 055/091 055/088 058/081 056/083 056/085 057/087
    02/T    10/U    11/U    13/T    55/T    44/T    33/T

&&

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

&&

$$
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