Sonnette, Montana Weather Forecast Discussion

975
FXUS65 KBYZ 110827
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
227 AM MDT Thu Sep 11 2025
.KEY MESSAGES...
- Above normal temperatures again today.
- Isolated to scattered showers and thunderstorms today with a
  threat of strong winds and large hail this afternoon and
  evening.
- Good chance for precipitation (50-80% chance >0.25in, greatest
  east of Billings) and cooler temps Friday into Sunday.
&&
.DISCUSSION...
Through Friday...
Active night as weak perturbations within the diffluent flow
aloft track south to north over our region. Strong storms over
east central MT have lifted north, but light showers and
occasional lightning moving across our western zones at this time.
Currently, we have a large upper low over the western CONUS
centered near NW Nevada. This has our region under the
aforementioned diffluent south/southwest flow with several minor
short waves ejecting from the main upper low. Easterly low level
flow has brought decent moisture into the area and MUCAPE is
progged to range from 300 J/kg west to 1500 J/kg east this
afternoon. Height falls will increase lapse rates and shear is
moderately in the 30-40 kt range with the nose of upper jet
starting to sneak into the picture. Timing may be an issue as
some of those weak short waves may move over the area in the
morning and early afternoon before peak heating. However, CAMs
seem to consistently point toward a scenario where main convection
develops over higher terrain (Beartooths) by mid afternoon and
propagates north/northeast through our central zones in the late
afternoon and evening. The ingredients here suggest severe wind
gusts and isolated large hail with brief heavy rain are possible.
Marginal/Slight Risk for severe storms outlined over our region by
SPC looks reasonable. Keep an eye on the sky this afternoon into
the evening!
Models show most of the convection lifting north of our CWA by
late evening. There is a hint of some lingering showers over our
central and eastern zones under the nose of the 300mb jet
overnight into Friday morning.
For Friday...Upper trough will be over the Great Basin with
similar flow pattern across our region. Generally expect a repeat
of Thursdays convection, but a better chance of hitting some of
our more eastern counties. Isolated strong storms are still
possible, but low levels will be a little cooler and wetter, thus
lapse rates will not be quite as steep as Thursdays. Thus, threat
does not seem as great as Thursdays except perhaps along the
Dakota borders.
Temperatures today will remain warm in the upper 70s west to near
90 east. Readings tomorrow 70s west to lower 80s east. Overnight
lows will range in the 40s and 50s. BT
Friday night through Wednesday...
Friday into Saturday, ensembles are currently showing energy from
a 500 mb trough splitting to the north and south of our region.
Their progression through the weekend differs on if any kind of
forcing will be present over our central zones. With this, there
is still a good amount of uncertainty in the precipitation
forecast, especially for eastern MT. This is likely from the
potential of a band of precip stretching southward from the low.
Currently, there is a 40-60% chance for at least a half an inch of
precipitation for Billings east Friday through the weekend. Near
the MT/ND border there is about a 30-40% chance of an inch for
this same time frame. With moderate shear and instability present
Friday, there could also be a few strong thunderstorms around
mainly producing gusty winds.
After this low exits the region Sunday, another looks to move into
western MT late Monday into Tuesday. This will keep the area in an
unsettled pattern with near normal temperatures.
High temperatures will be in the 70s to low 80s through the period
with Monday being the warmest day. TS
&&
.AVIATION...
Showers and thunderstorms this past evening will be exiting the
area overnight. A low level jet over eastern MT will create some
low level wind shear through sunrise. Isolated to scattered
showers and a few embedded thunderstorms are expected across the
region through the morning. Potentially stronger showers and
thunderstorms will again begin developing over high terrain around
20-21Z this afternoon, moving northeast onto the plains through
the afternoon. Wind gusts of 40 to 50 kts are expected with any
stronger storms that develop. TS
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Fri     Sat     Sun     Mon     Tue     Wed
-------------------------------------------------------
BIL 083 054/081 055/076 053/080 055/080 053/071 051/074
    5/T 23/T    45/T    21/B    13/T    44/W    32/W
LVM 079 044/078 044/076 045/078 045/075 043/069 042/073
    4/T 23/T    35/T    21/U    25/T    44/T    22/W
HDN 085 052/082 053/075 050/080 051/082 050/072 049/073
    4/T 22/T    55/T    31/B    12/T    53/W    42/W
MLS 088 057/083 057/074 053/078 054/083 053/074 053/072
    1/B 31/B    57/T    41/B    11/U    43/W    43/W
4BQ 087 057/081 057/070 053/075 053/081 052/073 051/069
    2/W 21/B    67/T    42/W    11/U    43/T    43/W
BHK 090 054/083 054/073 051/075 050/081 050/075 048/070
    1/U 20/B    67/T    52/W    11/U    33/W    43/W
SHR 085 049/080 049/073 045/075 047/081 046/072 045/071
    2/T 23/T    67/T    32/T    12/W    44/T    43/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings

NWS BYZ Office Area Forecast Discussion