textproduct: Great Falls

KEY MESSAGES

- Breezy to windy conditions develop across some areas today and become more widespread this weekend.

- Scattered showers and thunderstorms Saturday then turning much cooler with additional showers Sunday.

- Low pressure traversing the Northern Rockies next week may bring several rounds of precipitation Tuesday through Thursday.

DISCUSSION

/Issued 447 AM MDT Fri Jun 5 2026/

- Meteorological Overview:

A low-amplitude upper level ridge transits the Northern Rockies and MT today bringing the warmest and driest conditions of the next seven days before an upper level low/trough, currently offshore of BC moves into the NW US this weekend. Breezy west to southwest winds develop today as flow aloft shifts more southwesterly behind the exiting upper ridge with gusts in excess of 35 mph primarily confined to areas along the Rocky Mtn Front as the surface pressure gradient across the Rockies increases today and over portions of SW MT where deeper afternoon mixing is achieved.

A Pacific cold front crosses the Northern Rockies Saturday with moisture gradually increasing within the southwest flow aloft. A few showers develop behind the front across north-central/central MT early Saturday with showers and a few thunderstorms tracking northeast from southwest MT Saturday afternoon through eastern portions of north-central MT Saturday evening.

A stronger shortwave rotates through the trough across the Rockies Saturday night through Sunday, spreading much cooler temperatures across the area along with more widespread showers and perhaps a few thunderstorms. Snow levels fall to around 7000 ft Sunday and potentially as low as 6000 ft with the coldest air aloft passing across the area Sunday afternoon. This could bring some snow as low as passes across central and southwest MT, however afternoon timing will limit the potential for accumulation. Gusty west winds and afternoon temperatures in the 50s (upper 30s/40s in the mountains) on Sunday may impact those with outdoor recreation plans in the mountains. Clearing is expected Sunday night as the trough lifts out of the area with overnight low temperatures reaching the 30s to around 40 across most of the forecast area.

A fairly active/unsettled weather pattern persists next week with mainly dry conditions and seasonable warmth Monday before the next larger scale upper trough/low drops into the western US for the remainder of the week. While there is good overall agreement on the broader trough and increasing confidence in widespread precipitation, there is still a fair amount of variation in timing and placement of the upper low with probabilities for 0.50" or greater precipitation amounts (Tues- Thurs) ranging from 50-70% across much of the area.

- Forecast Confidence & Scenarios:

Surface instability on Saturday is limited to southwest MT Saturday afternoon with some elevated instability behind the front across eastern portions of north-central MT Saturday afternoon/evening. The risk for strong thunderstorms is primarily across northeast MT, but enough shear/wind aloft will exist for a small risk of strong wind gusts across the eastern-most portions of southwest and north-central MT.

Coolest temperatures Sunday night will be across southwest MT where winds will be lighter. The risk for frost (Min temp <36F) Sunday night/early Monday morning across southwest MT valleys is 80% or higher, including the Gallatin Valley.

AVIATION

05/18Z TAF Period

VFR conditions are expected to prevail at all terminals through the period. Westerly flow aloft turns southwesterly later today and tonight with increasing high clouds this afternoon through tonight. Breezy southwest winds develop at most terminals this afternoon with gusts as high as around 30kts at KEKS and KCTB. Hoenisch/thor

PRELIMINARY POINT TEMPS/POPS

GTF 79 49 72 46 / 0 10 20 50 CTB 72 44 66 39 / 0 0 30 10 HLN 80 49 74 45 / 0 0 30 40 BZN 82 46 80 44 / 0 0 20 40 WYS 75 39 76 41 / 0 0 10 20 DLN 82 46 78 44 / 0 0 20 30 HVR 79 48 77 45 / 0 20 20 50 LWT 79 46 77 42 / 0 10 20 50

TFX WATCHES/WARNINGS/ADVISORIES

None.