textproduct: Great Falls

KEY MESSAGES

- It will be dry and breezy through Thursday.

- Precipitation and cooler temperatures with mountain snow is expected Friday through this weekend.

DISCUSSION

/Issued 535 PM MDT Wed Sep 9 2026/

- Meteorological Overview:

This afternoon there is an upper-level ridge over North-central, Central, and Southwestern Montana. This will bring dry and warm temperatures (near seasonal averages) to the area on Wednesday. This afternoon the pressure gradient increases which will bring breezy conditions to the Rocky Mountain Front. On Thursday the upper-level ridge begins to break down. This will keep warmer temperatures with mostly dry weather for the area on Thursday. Thursday evening a cold front will move through North-central, Central, and Southwestern Montana.

On Friday zonal flow is over North-central, Central, and Southwestern Montana. This combined with the cold front that moved through will bring cooler temperatures (well-below seasonal averages). On Friday there will be rain showers across North- central, Central, and Southwestern Montana. On Saturday an upper- level ridge builds in briefly over North-central, Central, and Southwestern Montana. This will briefly bring dry conditions to all but the Rocky Mountain Front and status quo temperatures to the area. Sunday through Monday there will be upper-level closed low that will bring cooler temperatures and widespread precipitation to the area. Higher elevations locations have the potential to receive snow Friday through Sunday. See the Forecast Confidence & Scenarios Section for details. -IG

- Forecast Confidence & Scenarios:

On Thursday there is greater than a 60% chance for wind gusts of 45 mph or greater across the Rocky Mountain Front and Plains west of 1- 15, the Hi-Line, and Cascade to Judith Basin County. On Thursday along the Rocky Mountain Front there is a 60 - 80% chance for wind gusts of 55 mph or greater.

Saturday through Sunday there is a 40 - 60% chance for 4 inches of snow or greater along the Rocky Mountain Front. Saturday through Sunday there is a 30 - 60% chance for 2 inches of snow or greater across the Little Belts and mountains of Southwestern Montana. Sunday morning there is a 20 - 40% chance for low temperatures of 36 degrees or less across the plains of North-central Montana. On Monday there is a 60 - 80% chance for low temperatures of 36 degrees or lower across the lower-elevations of North-central, Central, and Southwestern Montana. On Monday there is a 30 - 50% chance for low temperatures of 34 degrees or lower across the lower-elevations of North-central, Central, and Southwestern Montana.

On Friday there is a 50 - 70% chance for a quarter inch of precipitation across the majority of North-central Montana. On Saturday there is a 50% chance for a quarter inch of precipitation or greater along the Rocky Mountain Front. On Sunday across Central and North-central Montana there is a 50 - 70% chance for half an inch of rain or greater. On Sunday there is 30 - 60% chance for a quarter inch of rain or greater across Southwestern Montana. -IG

AVIATION

10/06Z TAF Period

High confidence in VFR condition across all terminal through the TAF period. I added LLWS to the prevailing groups for terminals KCTB and KHVR as model soundings and surface observations continue to suggest boundary layer decoupling is ongoing leading to stark differences between surface and 2kft winds. Breezy conditions will be the theme through much of the day especially across North Central Montana. Widespread wind gusts of 20-35kt are expected area wide, with terminals KCTB, KGTF, and KHVR likely seeing gusts on the upper end of that range. Winds will remain through the period, only lightening up towards the immediate end. -JR

For KGTF: Odds of LLWS has dropped from the previous discussion as mixing has proved efficient at keeping surface winds up. Winds will again ramp up into the afternoon with a slightly more favorable southwest direction (220-230 degrees) through 10/18z when probability of crosswind criteria exceedance is low (30%). Following that, winds will become more westerly (250-270 degrees) and confidence in both critical sustained and gust crosswinds rises greatly to >60%. As we near the end of the TAF period winds will become weaker while maintaining the westerly component thus the risk of 15kt cross winds decreases but still remains high especially with any sporadic gusts.-JR

PRELIMINARY POINT TEMPS/POPS

GTF 76 55 80 48 / 0 0 10 80 CTB 69 51 72 42 / 0 0 0 60 HLN 75 49 84 50 / 0 0 0 60 BZN 76 45 84 48 / 0 0 0 0 WYS 69 33 72 37 / 0 0 0 0 DLN 77 43 82 46 / 0 0 0 0 HVR 75 50 81 44 / 0 0 0 50 LWT 72 50 83 47 / 0 0 0 70

TFX WATCHES/WARNINGS/ADVISORIES