Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
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