Sidney, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

105
FXUS65 KGGW 260640
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
1240 AM MDT Sun Jul 26 2026

.KEY MESSAGES...

- Dangerously hot high temperatures near or above 100 degrees are
  expected today. Look for little overnight recovery with lows
  this morning in the upper 60s to the lower 70s.

- Models hint at a smoke plume dropping into the Missouri Breaks
  and reducing visibility quite a bit this afternoon and evening.
  Not sure on the intensity and extent yet.

- Hot temps with near 100s may occur each afternoon through
  Wednesday. especially across the Missouri Break and Yellowstone
  Valley, but some overnight recoveries are possible beginning
  tonight.


&&

.DISCUSSION...

WEATHER PATTERN OVERVIEW:
Upper ridging over the western U.S. will remain the dominant
force this weekend with triple digit heat during the afternoon
hours today. Low temperatures this morning will struggle to get
down to the upper 60s to lower 70s, making for uncomfortable
sleeping conditions for those without air conditioning. The
Extreme Heat Warning continues through 10pm this evening.

Nighttime Microphysics on GOES Satellite showcase a large red
smoke plume stretched from eastern Oregon to north central Montana
which is pretty high in the atmosphere. Air Quality sensors
across western Montana at higher elevations are quickly trending
air quality down across those areas and HRRR/RAP Smoke models are
indicating that this will get caught in the boundary layer this
afternoon and dragged down into the Little Rockies and Missouri
Breaks. Mixing and mid level intensities of smoke concentrations
can be hit-and-miss when coming out of the mountains. Therefore
the intensity of the visibility drop and areal extent as it
reaches the surface are low confidence. However, we should not be
surprised is a dense Smoke Advisory and air quality alert were to
go out by mid-afternoon and this will need to be monitored.

Ensembles continue to show the hot temperatures continuing through
at least mid-week and possibly into the weekend with highs in the
90s to around 100 degrees each day. Heat Advisories each
afternoon after today across varying areas may be necessary as we
get closer.


FORECAST CONFIDENCE & DEVIATIONS:
NBM Deviations include... slightly lower MinRH today and tomorrow
afternoon to mesh up with neighbors, Higher hourly PoPs through
6AM for exiting morning showers, and HRRR/RAP blends to enhance
visibility reductions due to smoke through the day.

There is MODERATE to HIGH confidence in the heat products through
today.

There is LOW confidence for a dying thunderstorms to produce a
burst of wind across Petroleum and Garfield county this evening.

There is MODERATE to HIGH confidence in haze reducing visibility
as low as 4 SM this evening.

There is LOW to MODERATE confidence in a visibility drops from
smoke becoming low enough for a Dense Smoke Advisory across the
Little Rockies and Missouri Breaks.

GAH


&&

.AVIATION...
LAST UPDATE: 0600Z.

FLIGHT CATEGORY: VFR - MVFR. Possible IFR

DISCUSSION: Upper ridging will continue to provide hot
temperatures to the region. There is high confidence (80-100
chance) in haze impacting TAF sites through the cycle. The lowest
most places should go is MVFR by tomorrow evening. Confidence is
much lower (5-15% chance) on Smoke reaching IFR levels during the
mid day to the evening hours. Highest smoke concentrations are
expected about a county SW of the terminals, but if this moves
north then the chances of IFR increase.

LLWS: The is a chance for low level wind shear from now through
15Z if a low level jet kicks in tonight. This should exit shortly
after sunrise.

DENSITY ALTITUDE: Increased density altitude is expected in the
afternoon and evenings through Wednesday as temps near or exceed
100. Extra power and longer runway will be needed for takeoffs.

WINDS: Light and slightly S in the early morning. TUrning NW in
the late morning and increasing to 10 to 15 kts in the afternoon.
Becoming light and variable tonight.

GAH


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 10 PM MDT this evening for Central
and Southeast Phillips-Central and Southern Valley-Daniels-
Dawson-Eastern Roosevelt-Garfield-McCone-Northern Phillips-
Northern Valley-Petroleum-Prairie-Richland-Sheridan-Southwest
Phillips-Western Roosevelt-Wibaux.


&&

$$

weather.gov/glasgow