textproduct: Great Falls

KEY MESSAGES

- Mild temperatures build back in over the plains today.

- Mainly light precipitation near the Idaho border in SW MT late tonight and Monday.

- Next widespread opportunity for precipitation look to be the Wednesday into Thursday timeframe.

DISCUSSION

/Issued 1200 AM MST Sun Mar 1 2026/

- Meteorological Overview:

Broad troughing across the eastern US combined with broad ridging well off the Pacific coastline is resulting in a zonal to weakly northwest flow aloft. Cool air at the surface over the plains will be eroded through the day today, allowing for a mild day for all except those in far northern Blaine County. A bit of patchy fog will be around early this morning before the cold surface air mass is mixed out.

An upper trough undercutting the broad ridging over the Pacific shifts toward northern CA later today, moving onshore and eventually over NV late tonight into Monday. Areas along the Idaho border in Southwest Montana look to be on the northern periphery of this system, which will result in some light precipitation at times tonight into Monday. The system overall isn't particularly cold, but will be cool enough to result in snow as the primary precipitation type in the mountains, with a mix of rain and snow at times at lower elevations.

Elsewhere across the region mild and dry conditions continue into at least Tuesday night. There continues to be some timing discrepancies between guidance for the next round of troughing moving onshore from the Pacific Wednesday into Thursday. The slower solution would keep the region dry through the day Wednesday, while the faster brings precipitation across the Continental Divide by the afternoon Wednesday. Additional discussion on this uncertainty will be in the confidence and scenarios section. The main takeaway at this point will be for slightly cooler temperatures by Thursday, with the best opportunity for precipitation across terrain of Southwest Montana and vicinity.

A northwesterly flow aloft then looks to develop Friday into the weekend, though there is considerable uncertainty as to whether this northwesterly flow aloft will be cyclonic or anti-cyclonic in nature. This will also be discussed further in the confidence and scenario section. -AM

- Forecast Confidence & Scenarios:

Wednesday into Thursday:

There still remains a nearly 50/50 split between ensemble members that keep the troughing consolidated over this timeframe vs members that result in some magnitude of splitting. Solutions that maintain the troughing (Would favor the higher end of the envelope for precipitation for most areas) progress the system through faster, while the scenarios that split the troughing (Would favor the drier end of the envelope) are slower to arrive. At this point areas along the Continental Divide and the mountains of Central and Southwest Montana are the only areas with a greater than 50% probability to see 0.25" worth of liquid from this system.

Friday into the weekend:

Ensembles support lingering upper level troughing across the far southwestern US over this timeframe, though the north-south positioning, as well as whether it will become a cutoff upper low or not, makes the forecast uncertain. A further north or stronger upper level system would favor a more cyclonic northwesterly flow aloft across the Northern Rockies (About 45% of ensemble members) favoring a slightly cooler and wetter scenario. A more southern or weaker upper level system would favor a more anti-cyconic flow aloft (55% of ensemble members) and as a result would favor a warmer and drier scenario. -AM

AVIATION

01/12Z TAF Period

Other than some patchy fog concerns over the plains this morning and breezy to windy conditions along the Rocky Mountain Front, there are no significant aviation concerns for most of the TAF period. Patchy fog development will be most likely near KCTB and KHVR, but the probability for impactful visibility reductions is currently running less than 20%. After 02/00Z, a trough moving towards the Great Basin area will bring low stratus and mountain obscuration over the higher terrain near the MT/ID/WY borders. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 55 26 56 30 / 0 0 0 0 CTB 52 23 54 31 / 0 0 0 0 HLN 54 30 54 29 / 0 0 0 0 BZN 56 31 56 27 / 0 10 10 0 WYS 43 27 44 16 / 40 60 60 20 DLN 55 33 53 26 / 0 10 20 0 HVR 46 20 51 26 / 0 0 0 0 LWT 53 29 53 29 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.