textproduct: Great Falls

KEY MESSAGES

- Mild and generally dry conditions will persist through Thursday morning.

- The next chance for widespread precipitation will be from Thursday afternoon through Monday morning.

- Mountain snow is likely with lower elevations below 6000ft more likely to see rain through at least Saturday evening.

DISCUSSION

/Issued 300 PM MDT Mon Oct 19 2026/

- Meteorological Overview:

Upper-level ridging will continue through the rest of today bringing mild temperatures to the region. Over the next couple days, an upper-level low will track south along the Pacific coast and briefly settle next to Central California. This influx of southwesterly flow will start to bring precipitation chances to Southwest Montana as early as Thursday morning ahead of an upper- level trough arriving.

Thursday into Friday, the upper-level trough comes through and brings more widespread chances for precipitation along with cooler temperatures that are expected to last through the weekend. With snow levels dropping as low as 5000ft initially, snow is expected across much of the mountains in Central and Southwest Montana. At lower elevations below 5000ft, rain is expected to be the dominant precipitation type as much of the precipitation is expected to move through the area before snow levels would otherwise drop low enough to produce lower elevation snow. That being said, significant uncertainty remains in how low snow levels will get and even slight adjustments could have significant impacts on the forecast.

- Forecast Confidence & Scenarios:

Lower Elevation Snow Potential: The highest uncertainty revolves around how quickly snow levels will drop and whether that will coincide with the precipitation. Currently snow levels are expected to drop below 4000ft on Sunday morning which is after the majority of the precipitation has exited the area. While there might be some snowflakes possible Sunday morning, it would not be particularly impactful given the current setup. Should the cold air arrive earlier or the precipitation continue longer depending on how fast the trough moves, these scenarios could impact how much snow is possible at the lower elevations. Right now the probability of locations below 4000ft seeing at least an inch of snow is about 10-20%. -thor

AVIATION

20/00Z TAF Period

A weak surface front will bring a northerly wind shift to the plains between 20/06 and 20/12Z; otherwise, winds will mostly be light. There is a possibility of a few lower clouds/patchy fog during/following the frontal passage, but there is less than a 10% chance of occurrence. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 40 56 37 70 / 0 0 0 0 CTB 36 55 31 66 / 0 0 0 0 HLN 36 61 34 67 / 0 0 0 0 BZN 35 63 34 66 / 0 0 0 0 WYS 26 59 28 61 / 0 10 0 10 DLN 35 63 37 64 / 0 0 0 0 HVR 34 60 32 68 / 0 0 0 0 LWT 41 57 34 69 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.