367
FXUS65 KBYZ 240147
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
747 PM MDT Thu Jul 23 2026

.KEY MESSAGES...

- Hotter and drier Friday into next week. Triple digit highs and
  warm nighttime lows expected, resulting in increased risk of
  heat related health impacts. Stay safe from the heat!

- Hot, dry and occasionally breezy conditions will increase fire
  concerns over the coming days. Lightning and thunderstorm wind
  gust potential on Saturday will exacerbate these concerns.

- Low risk (10-30%) of thunderstorms each day this weekend through
  the middle of next week.


&&

.UPDATE...

Isolated shower and weak thunderstorm activity continues to
diminish this evening. Replacing this activity is smoke from
western wildfires. This will bring smoky conditions into Friday
morning, before largely clearing by the afternoon. Look for very
warm and mostly dry conditions on Friday, before the chance for
convection increases late in the afternoon and evening. The rest
of the forecast remains on track. Matos

&&

.DISCUSSION...

Through next Thursday...

Weak shortwave continues to produce showers as of noon, mainly
SE of Billings, but we are starting to see development upstream
over central MT. Air mass remains very moist with pwats ranging
from an inch in our west to 1.5" in the east. Dew points from
Livingston to Harlowton are in the low 60s. Despite the transition
to large scale subsidence behind the wave, there should be enough
moisture for isolated to scattered thunderstorms this afternoon
and early evening. Mesoanalysis shows a surface trof from eastern
Musselshell to Big Horn Counties, and convergence along this axis
may be a focus for thunderstorm development. Something to keep an
eye on. Any of today`s storms could produce locally heavy rain and
erratic winds. Isolated weaker convection may eke into our west in
the late evening but HRRR has backed off somewhat on this.

Building ridge and shift to mixed west winds will push temps to
the upper 90s and lower 100s tomorrow. This marks the first of
what looks to be several days of heat as the intermountain west
ridge remains in place through much of next week. Ensembles and
cluster analyses show confidence here. Overall, look for high
temps from 95-105F each day through the extended period. As it
looks now, any break down of the ridge is expected to hold off
until we get into August.

Regarding the heat, extreme heat highlights are in effect tomorrow
through the weekend. Along with the daytime temps will come warm
nighttime lows, limiting relief. Please take precautions to
protect yourself from the heat.

Humidity over the past 7-10 days has prevented fire dangers from
elevating much. This is about to change. Today`s wave will scour
out the deep monsoon moisture and pwats will return to more
seasonable levels starting Friday, though they will remain a
little above normal for the next several days as we see occasional
pushes of mid-high level moisture from the south. Tomorrow`s
breezy/mixed west winds will accompany RHs falling to the teens.
This will elevate concerns during what looks to be a transition/
drying day for local fuels. Confidence has increased for a
monsoonal wave to bring scattered late day high-based
thunderstorms Saturday. These storms won`t be dry but precip will
be spotty. The combination of very hot temps, RHs in the teens,
increased lightning, and potential for strong convective surface
wind gusts, warrants a Fire Weather Watch for Saturday from noon
to midnight. Sunday will also be hot and dry but w/ lesser t-storm
potential, and a weak backdoor wind shift. North winds may be
somewhat breezy in the east.

As already mentioned, the forecast for next Monday through
Thursday will be characterized by above normal temps and a daily
risk (10-25% chance) of diurnal thunderstorms. Pwats remain
slightly wetter than normal so the storms won`t be dry, but they
will be high-based and have potential to produce gusty/erratic
surface winds, which with the lightning itself will be problematic
for any new fires that develop over the coming days.

Finally for those keeping up on the July 25th drama. Billings
airport has never (since 1934) reached 100F on this date, but it
really should happen this year. Current forecast is for 102F,
consistent with 700mb temps of +16C and deep mixing. With the
water vapor transport and eventual convection on Saturday, it is
at least plausible that cloud cover holds back surface heating
just a bit. The July 25th record is 98F, so it is possible to
break the record and still not reach 100F. Stay tuned.

JKL


.AVIATION...


Isolated showers and weak thunderstorms will continue to decrease
in coverage this evening into tonight. After a dry morning on
Friday, another round of isolated to scattered showers and weak
thunderstorms is forecast during the afternoon and evening. With
this activity both days, moderate rain and gusty winds are the
main threats.

Wildfire smoke from distant wildfires will reduce slant range
visibility this evening into Friday. Expect smoke concentrations
to increase to the north, with the highest smoke concentrations
over northern Montana.

Very hot daytime temperatures in the upper 90s to mid 100s
(degrees Fahrenheit) Friday through Sunday will also lead to a
high density altitude at times during the day. LA
&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 069/101 069/102 068/100 068/096 067/098 067/097 067/098
    11/G    12/T    21/U    21/U    10/U    11/U    21/U
LVM 059/099 060/099 059/098 058/093 057/094 057/096 058/097
    22/N    23/T    32/T    21/U    10/U    11/U    21/U
HDN 064/101 065/105 066/101 066/098 065/099 065/099 065/099
    11/G    11/G    20/G    21/U    11/U    11/U    21/U
MLS 068/102 068/107 073/102 070/100 068/100 069/101 069/099
    10/G    00/G    20/G    21/U    21/B    11/G    21/U
4BQ 065/100 068/105 071/101 069/099 068/097 068/098 068/096
    11/U    20/G    20/G    21/B    21/B    22/T    32/T
BHK 063/101 065/107 069/102 065/100 064/098 064/099 064/097
    10/N    00/G    20/G    21/B    21/B    22/T    32/T
SHR 059/100 060/103 064/100 063/095 062/094 062/095 061/094
    22/U    22/T    11/U    11/U    12/T    12/T    12/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Extreme Heat Warning in effect from 9 AM Friday to 9 PM MDT
      Sunday FOR ZONES
      29>34-36-37-42-57-58-138-139-169-170-173-235.
     Heat Advisory in effect from 9 AM Friday to 9 PM MDT Sunday
      FOR ZONES 40-56-63>66-141-172-228.
     Fire Weather Watch in effect from Saturday afternoon through
      Saturday evening FOR ZONES 123>133.
WY...Extreme Heat Warning in effect from 9 AM Friday to 9 PM MDT
      Sunday FOR ZONE 199.
     Fire Weather Watch in effect from Saturday afternoon through
      Saturday evening FOR ZONES 274-284.

&&

$$
weather.gov/billings