textproduct: Great Falls

KEY MESSAGES

- It will be windy this afternoon across the plains of North- central Montana.

- It will cool down to well-below seasonal average temperatures by Sunday.

- It will be mostly dry until Saturday afternoon with lower- elevation and mountain snow possible on Sunday and Monday.

UPDATE

The upper level system that brought very windy conditions to the region today continues to track east and away from the area across the Canadian Prairies. Decreasing mid-level winds and surface pressure gradient across the area has allowed winds to gradually lower and remaining portions of the High Wind Warning were ended with only areas along the immediate east slopes of the Rocky Mtn Front and portions of Blaine county still likely to see a few gusts in excess of 40-50 mph through the remainder of this evening. A westerly upper level jet remains positioned across the Pacific NW and Northern Rockies with a weak disturbance passing later tonight through Friday morning, bringing a period of increased clouds and perhaps some very light rain/snow showers along northern portions of the continental divide before clouds decrease with another breezy afternoon on Friday. Hoenisch

DISCUSSION

/Issued 544 PM MDT Thu May 14 2026/

- Meteorological Overview:

This afternoon there is an upper-level trough over North-central, Central, and Southwestern Montana. This afternoon there remains a strong pressure gradient. This combined with strong low and mid- level winds will bring windy conditions to North-central Montana. This afternoon across the plains of North-central Montana the strong winds are causing blowing dust to reduce visibility. This afternoon there will be snow showers along the Rocky Mountain Front. This afternoon temperatures will be around seasonal averages. On Friday zonal flow is over North-central, Central, and Southwestern Montana. This will allow it to be mostly dry with about seasonal averages for temperatures.

On Saturday an upper-level trough associated with a surface cold front begins to move over North-central, Central, and Southwestern Montana. This will bring precipitation and cooler temperatures to the area on Saturday. On Sunday the upper-level trough remains over North-central, Central, and Southwestern Montana. This will bring well-below seasonal averages for temperatures on Sunday. On Sunday there will be widespread precipitation across the area. Across mountain locations this will be primarily snow. At lower-elevations this will be a rain/snow mix. Sunday afternoon there is enough instability around that there is the potential for a few rumbles of thunder as well. On Monday the upper-level trough remains over North- central, Central, and Southwestern Montana. As a result precipitation and cold temperatures (well-below) seasonal averages will linger across the area. On Tuesday and Wednesday an upper-level ridge builds in over North-central, Central, and Southwestern Montana. This will allow temperatures to gradually warm up with mostly dry weather. -IG

- Forecast Confidence & Scenarios:

On Saturday there is a 10 - 20% chance for thunder across Southwestern Montana. On Sunday there is a 15 - 25% chance for thunder across most of North-central, Central, and Southwestern Montana. Sunday through Monday there is a 10 - 50% chance for greater than a tenth of an inch of snow across the lower-elevations of North-central, Central, and Southwestern Montana south of the Montana 200 Corridor. Across the mountains of North-central, Central, and Southwestern Montana there is a 50 - 80% chance for 4 inches of snow or greater. One area of uncertainty with this snowfall is when it falls will have drastic differences on impacts. If snow falls during daylight hours there will be minimal impacts. However if snowfall falls over night this has the potential to lead to some impacts. Another area of uncertainty with this systems precipitation types is when the cold air moves in and transitions precipitation at the lower-eelvations from rain to snow.

On Sunday across most of the lower-elevations of North-central, Central, and Southwestern Montana there is a 20 - 50% chance for high temperatures of 45 degrees or colder. Monday morning there is a 30 - 50% chance for low temperatures of 28 degrees or colder across the lower-elevations of North-central, Central, and Southwestern Montana. On Sunday morning across the lower- elevations of Southwestern Montana there is greater than a 40% chance for low temperatures of 28 degrees or colder. -IG

AVIATION

15/00Z TAF Period

Gusty westerly winds will continue across the region this afternoon, producing patchy blowing dust. The gusty winds will dissipate this evening across the southwest terminals (KBZN, KEKS, and KWYS), before beginning to increase again tomorrow morning around 15Z. For the north-central and central terminals (KHLN, KGTF, KCTB, KHVR, and KLWT), the winds will decrease this evening, but remain gusty, before also increasing tomorrow morning around 15Z. VFR conditions will prevail throughout this TAF period across all terminals. -Dzomba

PRELIMINARY POINT TEMPS/POPS

GTF 42 62 40 58 / 0 0 0 20 CTB 37 57 34 54 / 0 0 0 0 HLN 39 63 38 56 / 0 0 0 40 BZN 36 65 35 60 / 0 0 0 30 WYS 31 63 30 57 / 0 0 0 0 DLN 36 65 37 60 / 0 0 0 10 HVR 40 65 37 63 / 0 10 10 0 LWT 38 61 36 59 / 0 0 0 30

TFX WATCHES/WARNINGS/ADVISORIES