textproduct: Great Falls

KEY MESSAGES

- It will be dry Wednesday through Friday.

- It will warm up through Saturday and then cool back down to seasonal averages Sunday and Monday.

- Thunderstorms return this weekend with breezy conditions Saturday evening through Sunday.

DISCUSSION

/Issued 149 AM MDT Wed Aug 19 2026/

- Meteorological Overview:

Today an upper-level ridge begins to build back in across North- central, Central, and Southwestern Montana. Today temperatures will be around seasonal averages with dry weather. On Thursday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will keep warm and dry conditions for the area on Thursday. Today and Thursday upper-level shortwaves will move through the upper-level flow and bring breezy conditions to North-central, Central, and Southwestern Montana.

On Friday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will bring hot and dry weather to the area. An upper-level shortwave will move through the upper-level flow and bring breezy conditions to North- central, Central, and Southwestern Montana. On Saturday an upper- level trough begins to move over North-central, Central, and Southwestern Montana. Due to southwest flow aloft monsoonal moisture will return to Montana on Saturday. This will bring showers and thunderstorms back to the area. Due to modestly strong low-level and mid-level winds it will be breezy on Saturday evening. On Sunday the upper-level trough is over North-central, Central, and Southwestern Montana. This will cool down temperatures slightly and due to the monsoonal moisture bring another round of showers and thunderstorms to the area. On Sunday due to modestly strong low and mid-level winds it will be breezy across North-central, Central, and Southwestern Montana. On Monday an upper-level ridge moves back over North-central, Central, and Southwestern Montana. This will bring warm weather and mostly dry weather to the area on Monday. On Tuesday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will bring another day of warm and mostly dry weather to the area on Tuesday. -IG

- Forecast Confidence & Scenarios:

On Saturday there is a 30 - 45% chance for thunderstorms in Southwestern Montana. On Saturday there is a 15 - 30% chance for thunderstorms across North-central and Central Montana. On Sunday there is a 25 - 35% chance for thunderstorms across Central and Southwestern Montana. On Sunday there is a 15 - 20% chance for thunderstorms across North-central Montana. Saturday through Sunday there is a 25 - 50% chance for a quarter inch of rain or greater across Southwestern Montana. Precipitable Water (PWAT) will increase this weekend which has to potential to lead to localized flash flooding on burn scars with the stronger thunderstorms.

On Saturday there is greater than a 50% chance for wind gusts of 25 mph or greater across North-central, Central, and Southwestern Montana. On Saturday in northern Blaine County there is greater than a 70% chance for wind gusts of 40 mph or greater. On Sunday there is greater than a 50% chance for wind gusts of 30 mph or greater across North-central, Central, and Southwestern Montana. On Sunday there is a 50 - 75% chance for wind gusts of 40 mph or greater along the Hi-Line, Southern Rocky Mountain Front, and in Cascade and Judith Basin County. On Sunday afternoon across North- central Montana there is a 15 - 30% chance for wind speeds of 15 mph or greater combined with relative humidity of 20% or less (red flag criteria). On Sunday there is low confidence in relative humidity reaching critical levels and so at this time it appears on Sunday there will be at least elevated fire weather concerns due to gusty winds. -IG

AVIATION

18/12Z TAF Period

VFR conditions will prevail at terminals during this TAF Period with high-level clouds around and primarily light winds. During this TAF Period smoke from wildfires will reduce slantwise visibility across North-central Montana. -IG

For KGTF: Winds will be southwesterly at the beginning of this TAF Period and shift to more westerly by 16Z and shift to northwesterly by 23Z and be light and variable after 01Z. There is a 40% chance for a 15 kt crosswind between 20Z and 00Z.

PRELIMINARY POINT TEMPS/POPS

GTF 88 55 90 56 / 0 0 0 0 CTB 83 52 83 51 / 0 0 0 0 HLN 87 52 91 58 / 0 0 0 0 BZN 84 50 90 53 / 0 0 0 0 WYS 79 39 84 45 / 0 0 0 0 DLN 83 48 87 53 / 0 0 0 0 HVR 87 55 90 55 / 0 10 0 0 LWT 83 53 87 54 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.