textproduct: Great Falls

KEY MESSAGES

- It will be breezy this afternoon and Saturday.

- It will be hot and dry through Tuesday.

- A brief cool down is expected Wednesday through next Friday with isolated showers returning primarily to North-central Montana.

UPDATE

/Issued 607 PM MDT Fri Aug 7 2026/

Early evening update has been published, with the main adjustment being to re-run smoke grids to incorporate latest Hi-Res guidance with respect to smoke dispersal. The Moose, Sand Creek, and Bobcat Lakes fires burning within the Beaverhead-Deerlodge National Forest have been producing a significant amount of smoke this afternoon due to critical fire weather conditions, with pyrocumulus even being produced over the Sand Creek Fire. This smokehas resulted in reductions in visibility across much of Central and Southwest Montana as westerly winds transport the smoke eastward, especially along and south of the Interstate 90 corridor where visibilities have fallen to as low as 2 to 4 miles. The remainder of the forecast remains on track and no other adjustments were made. - Moldan

DISCUSSION

/Issued 607 PM MDT Fri Aug 7 2026/

- Meteorological Overview:

This afternoon/evening an upper-level ridge will flatten. This will keep warm temperatures and dry weather across North-central, Central, and Southwestern Montana this afternoon. Associated with the upper-level ridge flattening there is modestly strong low- level and upper-level winds. This will bring breezy conditions to the area this afternoon and evening. On Saturday there will be upper-level zonal flow over North-central Montana. This will allow the warm and dry conditions to persist. Due to modestly strong low-level and mid-level winds it will also be breezy across North-central, Central, and Southwestern Montana. On Sunday upper-level zonal flow persists over North-central, Central, and Southwestern Montana until Sunday afternoon/evening when an upper-level ridge builds back in over the area. This will bring slightly cooler temperatures to the area with dry weather. Smoke from regional wildfires will be around throughout the next few days.

On Monday and Tuesday the upper-level ridge remains over North- central, Central, and Southwestern Monday. This will keep warm and dry weather for the area on Monday and Tuesday. Wednesday through next Friday the upper-level ridge remains over North- central, Central, and Southwestern Montana. Wednesday through Friday monsoonal moisture gradually makes it up to Montana. This will bring precipitation chances and cooler temperatures to the area Wednesday through next Friday. Wednesday through Friday the greatest forcing is along the Hi-Line and so that is where the greatest chances for precipitation are. See the Forecast Confidence & Scenarios section for details. -IG

- Forecast Confidence & Scenarios:

On Saturday there is greater than a 70% chance for wind gusts of 25 mph or greater across most of North-central, Central, and Southwestern Montana. On Saturday the HREF (Hi-resolution Ensemble Forecast) has a 50 - 70% chance for wind speeds of 15 mph or greater and relative humidity less than 20% across much of Fergus County and portions of Choteau County. Since the majority of the zone will not have 15 mph wind speeds and/or consistent wind gusts in excess of 25 mph combined with relative humidity less than 20% for three hours and since this is a marginal event at this time a Red Flag Warning was not issued for the Fire Weather Zone containing most of Fergus and Choteau Counties.

On Wednesday there is a 30% chance for thunderstorms across the Hi- Line and a 15% chance for thunderstorms across the rest of North- central, Central, and Southwestern Montana. On Thursday and Friday there is a 15 - 30% chance for thunderstorms across most of North-central Montana. Wednesday through Thursday there is a 60% chance for a quarter inch of rain or greater along the Hi-Line. Across the rest of North-central Montana there is a 20 - 40% chance for a quarter inch of rain or greater Wednesday through Thursday. -IG

AVIATION

08/06Z TAF Period

VFR conditions will prevail throughout this TAF period. The exceptions are at KBZN, KEKS and KHLN, which will see periods of MVFR conditions due to wildfire smoke causing a reduction in visibility. For all the terminals, there will be times of reduced slant range visibility due to smoke produced from regional wildfires.

Overall, KBZN and KEKS will see the greatest impact on visibilities due to smoke from fires in the Pioneer Mountains. Due to these thick smoke plumes, cloud bases are around 4500-5000 ft for the beginning period of these two TAFS. It should be noted that visibility will likely be lower tonight across SW MT than what the ASOS are reporting due to a nighttime algorithm being used.

Winds will remain generally light and variable, with westerly winds increasing around 18-20Z, especially in SW MT. Gusts between 15-20 kt can be expected. While visibilities across the region will improve slightly in the morning, these afternoon westerly winds will cause a return of wildfire smoke.

KGTF: While skies will remain FEW250 to clear, slant range visibilities will be reduced due to smoke from regional wildfires. Winds will be light and variable until around 19Z, in which a southwesterly wind will increase to 7-9 kts. At 16Z, winds become predominately westerly, with chances for gusts in excess of 15 kt increasing to 30%. By 22Z, winds become northwesterly and chances for gusts in excess of 15 kt increase to 50-60%. By 09/05Z, chances for gusts in excess of 15 kt decrease to less than 5%. -Dzomba

FIRE WEATHER

A Red Flag Warning remains in effect for the southern districts through Saturday. The combination of gusty afternoon winds, low humidity and hot temperatures will create critical fire weather conditons. Because of all the smoke, some locations might not mix the winds aloft on Fri/Sat. No precipitation is expected through at least Sunday. IG/Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 53 89 57 86 / 0 0 0 0 CTB 50 82 51 79 / 0 0 0 0 HLN 57 92 57 90 / 0 0 0 0 BZN 54 92 54 90 / 0 0 0 0 WYS 43 88 45 88 / 0 0 0 0 DLN 53 91 53 89 / 0 0 0 0 HVR 51 87 56 86 / 0 0 0 0 LWT 54 87 55 83 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 9 PM MDT Saturday for Central and Eastern Lewis and Clark National Forest Areas-Helena and Townsend Ranger Districts of the Helena National Forest-Lincoln Ranger District of the Helena National Forest.