216
FXUS65 KBYZ 090754
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
154 AM MDT Wed Jul 9 2025

.KEY MESSAGES...

- Hot today (90s to 103). Heat Advisory in effect for portions of
  the area 9am-9pm today.

- Isolated mainly dry thunderstorms with strong wind gust
  potential this afternoon/evening.

- Cold front brings increasing chance of precipitation late
  Thursday into Friday; Highs in the 70s Friday.

- Turning warmer again for the weekend.

&&

.DISCUSSION...

Through Thursday night...

Temperatures reached the mid to upper 90s over central portions of
the forecast area Tuesday. Western foothills and areas along the
eastern state line were a bit cooler. Forecast for today looks to
be around 5 degrees warmer pushing central zones into the triple
digits. Going Heat Advisory is on track for current zones.
HeatRisk forecast has recommended adding in zones along the MT/WY
border as well, and will update the advisory for these inclusions.

Continue to see an advertisement in the models for isolated high
based convection this afternoon dispersed across the forecast area
this afternoon into the evening hours. As mentioned in earlier
discussions, the capping temperature for our area is around +12C
at 700mb. The forecast for tomorrow afternoon shows +13C over
northeast zones and widespread +15 to +16C elsewhere suggesting
convection is going to have a very tough time getting going. For
example convection Tuesday was less than models anticipated and
very high based (no precipitation hitting the ground) with only a
couple of lightning strikes. This was with 700mb temperatures
around +13C, so today is going to be even more difficult.

That said can`t ignore the model suggestions completely and the
threat for strong wind gusts with any convection that does manage
to persist and generate virga is not inconsequential, though it is
less than was advertised in yesterdays model runs. The SPC
Marginal risk over the forecast area today is for this strong wind
threat but is contingent on a few storms managing to persist
despite the warm mid level temperatures, which once again is going
to be tough. The best chance for a storm to get going an persist
is going to be along the wind shift/cold front that moves into the
area during the evening hours. The convergence combined with a
bit more moisture riding in with the northwest winds might be
enough to get something more robust and generate those strong wind
gusts.

Cooler air trickles into the area late Wednesday night into
Thursday dropping temperatures about 10 degrees off of Wednesdays
highs, mainly in the mid to upper 80s. Most of the day Thursday
looks dry. The main core of the upper level trof and subsequent
surface cool airmass pushes into the area Thursday evening. This
cool air intrusion will boost moisture and precipitation potential
Thursday night into Friday morning. The latest precipitation
probabilities are lower than they were this time yesterday in the
NBM at 40 to 60 percent Thursday night, and 20 to 40 percent
Friday morning. Accumulations have also diminished by about half
of what they were yesterday, to generally under 0.15 inches. This
decrease is due to a trajectory change to the path of the core of
the upper trof from driving southeast across our area to shifting
more eastward instead of digging southward with time. Snow levels
have also increased over yesterdays runs to around 11000 feet due
to the systems path change. No longer looking like an impactful
snow for the Beartooth Pass, however folks recreating in the high
country should continue to be prepared for cold temperatures and
precipitation, with some snow in the highest elevations. Chambers

Friday through Tuesday...

Cool temperatures in the forecast for Friday with most locations
showing highs in the 70s. Precipitation chances diminish quickly
from northwest to southeast in the early morning as drier air
arrives on northwest winds.

The cool temperatures are short lived as flat west/northwest flow
aloft and dry air over the area will allow temperatures to reach
the lower 90s in many areas on Saturday, with plenty of sunshine.

As with the past few days, the forecast from Sunday into early
next week remains uncertain. Deterministic NBM continues to
advertise warm conditions through Monday, with lots of lower 90s,
before a cold front arrives Tuesday dropping temperatures toward
80 degrees through Wednesday. The spread on the NBM however shows
increasing uncertainty with temperature spreads increasing to
around 10 degrees Sunday and Monday, and 15 degrees heading into
Tuesday. The deterministic GFS and ECMWF both show a couple of
shots of northerly winds pushing into the area from Saturday night
through Monday, ahead of the stronger cold front Tuesday. Given
this the confidence in a continued hot/dry forecast from Sunday
into Tuesday has low confidence, with the potential for cooler
conditions than current NBM is advertising along with a better
chance for precipitation with the weak cold fronts/wind shift
boundaries in the area. Chambers

&&

.AVIATION...

06z Discussion...

Light winds and VFR conditions are expected to persist through
20z. Areas in south central Montana, esepcailly the foothills,
can see some gusts up to 25-30kts after 20z. Additionally some TS
are forecast to form over the mountains and move eastwards during
this time. These TS will have high bases (CIGs) and will pose a
threat for some gusty winds/downbursts with the strongest of
storms. While all sites in the forecast area have a slight chance
(~20%) of being impacted by storms, the higher likelihood will be
in places such as KBIL and KLVM (30% chance). Mountains will be
partially obscured with these storms. WMR

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 100 065/089 056/078 054/092 062/091 061/087 060/078
    2/T 21/U    51/B    00/U    00/U    11/U    23/T
LVM 096 054/086 048/077 048/088 054/089 052/087 051/078
    2/T 22/T    41/B    00/B    00/U    11/U    23/T
HDN 100 062/090 054/077 051/092 058/092 059/089 058/080
    2/T 21/U    62/W    00/U    00/U    11/U    32/T
MLS 101 066/092 056/079 055/090 061/091 061/088 059/079
    1/G 31/U    51/U    00/U    00/U    11/U    32/T
4BQ 099 065/088 057/074 053/088 062/089 061/087 060/079
    2/T 20/B    42/T    00/U    10/U    11/U    32/T
BHK 099 061/089 053/075 050/086 057/088 056/085 055/079
    0/U 21/B    41/B    00/B    00/U    01/B    22/T
SHR 099 059/087 050/072 046/087 055/089 055/086 054/078
    2/T 21/B    54/T    00/B    00/U    11/U    23/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Heat Advisory in effect from 9 AM this morning to 9 PM MDT
      this evening FOR ZONES
      29>33-36-37-57-58-138-139-169-173-235.
WY...Heat Advisory in effect from 9 AM this morning to 9 PM MDT
      this evening FOR ZONE 199.

&&

$$
weather.gov/billings