textproduct: Great Falls

KEY MESSAGES

- There will be periods of strong, gusty winds through early Saturday, mostly along the Rocky Mountain Front and the plains.

- Most locations will remain dry while temperatures climb to unseasonably warm levels through Friday.

- A Pacific trough and cold front looks to bring cooling temperatures and a brief period of showery conditions this weekend.

- Near average temperatures and unsettled conditions continue into next week.

DISCUSSION

/Issued 131 AM MDT Wed Mar 18 2026/

- Meteorological Overview:

An anomalously strong ridge of high pressure will remain entrenched over the Great Basin and southwestern CONUS through the first half of the weekend. The northern influence of this ridge will reach the Northern Rockies and warm temperatures to around 20 to 30 degrees above average by Thursday and Friday; however, westerly flow aloft be quite strong and subtle shortwaves will maintain scattered to broken middle and higher level cloudiness and even a few mostly mountain showers. This will also maintain daily rounds of strong, gusty winds, mostly along the Rocky Mountain Front and the plains.

While it looks windy everyday through early Saturday, the strongest H700 winds look to push through during the nighttime and early morning hours, which will place a heavier reliance on mountain wave activity to transfer the stronger gusts to the surface. Over the last couple of nights, instances these localized and shorter duration winds have mostly been occurring along the Rocky Mountain Front and on the north and east aspects of the central island ranges. Daytime winds will be mostly driven by diurnal mixing for the next day or so. A stronger H700 jet still looks to cross the Northern Rockies Friday afternoon through early Saturday in advance of an approaching Pacific trough/cold front and bring an opportunity for more widespread stronger winds.

Ensembles continue to agree with the ridge starting to weaken this weekend and allowing the aforementioned Pacific trough and cold front to move through the Northern Rockies on Saturday. This will bring a short period of showery, windy conditions while temperatures cool closer to average for at least a few days. By this time, A Canadian front should drop far enough south to shift the focus of stronger winds into southwest MT. Next week will see a continuation of unsettled conditions with near average temperatures. Another Pacific trough and cold front looks to move through by mid- next week. - RCG

- Forecast Confidence & Scenarios:

Windy conditions continue through Saturday...

Winds during the overnight hours have been overall lighter and more localized than last night. The one exception being a mountain wave over Cascade County that brought around an hour of 40 mph sustained winds and 60 mph gusts. This was mostly localized to areas over higher terrain with less of an impact on populated areas. Needless to say, it will be windy along the Rocky Mountain Front and in central/north-central MT over the next 72 hours with localized mountain wave activity each night followed by broad and general windy conditions during the day. Adding Fergus County was the only change to the inherited high wind warning that covered the Rocky Mountain Front zones, Eastern Glacier County, and the lower elevations of Judith Basin. The latest hires guidance suggests that the eastern half of Fergus County will see a period of stronger winds later this morning into the afternoon hours. A similar mapped warning may be needed again on Thursday.

Friday afternoon through Saturday, stronger winds aloft associated with the Pacific trough and cold front look to sweep through the Northern Rockies. The uncertainty that impacts the magnitude of winds for northern areas will be how fast a Canadian front moves south and undercuts the elevated winds aloft. The GFS suite typically handles these scenarios a little better than other ensembles and times the front to move southward into the plains sometime Saturday morning. This suggests the opportunity for stronger winds along the Rocky Mountain Front and the plains will roughly run from Friday afternoon through early Saturday before shifting the focus into southwest MT. NBM probabilities for 60 mph wind gusts on Friday and Saturday have gone down some and become a little more localized compared to 24 hours ago, but it still highlights the normal problem areas with a rough 30 to 60% chance, including the Rocky Mountain Front, plains west of of I15, central MT 87/200 corridor, and the narrow south to north oriented valleys of southwest MT. - RCG

AVIATION

18/12Z TAF Period

A moderate to strong west-northwesterly flow aloft over the Northern Rockies and MT will continue to produce mountain wave turbulence along with instances of low-level wind shear and periods of locally strong surface winds. There will be the presence of mostly mid - to high level cloud cover with some spotty areas of light precipitation developing across eastern portions of central/north- central MT between 18/14 and 18/19Z. The main impact from this will be some higher mountain obscuration; however, VFR conditions will generally prevail at the terminals. - RCG

FIRE WEATHER

Warm, dry, and windy conditions are expected to develop over Southwest MT Wednesday through Friday. Relative humidity dropping into the low to mid teens and wind gusts exceeding 30 to 40 mph look to develop critical fire weather conditions over Madison and Beaverhead Counties Wednesday through Friday. -Wilson

HYDROLOGY

Continued warming this week will continue to melt out recent heavy snowfall over the mountains and lower elevations in Judith Basin and Fergus Counties. A rise in small creeks and rivers are expected as a result, with some small creeks running high. Water ponding in fields and minor flooding in urban areas/door drainage areas due to clogged storm drains are possible. Along the Northern Rockies, snow levels rising to 7,000ft Wednesday will allow for rain to mix in with snow. However, moisture amounts remain light enough to keep river flooding potential low. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 63 48 68 50 / 10 10 0 0 CTB 58 41 64 41 / 10 0 0 0 HLN 65 39 71 43 / 0 0 0 0 BZN 71 38 75 41 / 0 0 0 0 WYS 57 23 61 29 / 0 0 0 0 DLN 70 38 72 41 / 0 0 0 0 HVR 67 41 71 43 / 30 0 0 0 LWT 62 42 68 46 / 20 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until 9 PM MDT this evening for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.

High Wind Warning from 9 AM this morning to 9 PM MDT this evening for Fergus County below 4500ft-Judith Basin County and Judith Gap-Snowy and Judith Mountains.