textproduct: Great Falls

KEY MESSAGES

- Southwest Montana remains mild for the next couple of days while cloudier and cooler conditions prevail over the plains.

- A fast moving cold front will bring a period of more widespread strong winds on Tuesday.

- Light mountain snow and lower elevation rain and snow showers develop Tuesday night into Wednesday.

- Another trough looks to move in during the second half of next weekend for another cool down and increased shower activity.

UPDATE

Northwest flow aloft, with a weak embedded wave moving southeast and over North Central Montana, will reside over the Northern Rockies through this Easter Sunday. At the surface a "cooler" airmass has settled into place across the plains of Central and North Central Montana thanks to the passage of a cold front on Saturday, with this front now stalled along a Rogers Pass, to Monarch, to Judith Gap line. High temperatures north of this stalled front will largely range from the low 40s to low 50s today, with the upper 50s to low 60s for points south across the valleys of Central and Southwest Montana. While most areas will remain dry through the day today a few rogue rain/snow showers can't be ruled out along the Hi-Line, mainly east of Cut Bank and north of the US Hwy 2 corridor. The on-going forecast remains on track and minimal updates were made. - Moldan

DISCUSSION

/Issued 535 AM MDT Sun Apr 5 2026/

- Meteorological Overview:

Northwesterly flow aloft will remain over the Northern Rockies for the next day or so while a 1040 mb surface high moves southeastward out of Canadian prairies into northern plains. This will bring a moist easterly flow in the low levels for cloudier and cooler conditions, particularly for central and north-central MT. There may be some patchy fog and spotty light precipitation, though easterly breezes should reduce fog impacts some and precipitation amounts look to be negligible and mostly concentrated along the Hi-Line.

On Tuesday, a compact Pacific trough and attendant cold front will bring a period of strong gusty winds to much of the forecast area. An H700/H500 60 to 80 kt jet, supported by cold air advection, looks to pass through during late morning and afternoon hours when diurnal mixing is near its peak. There will also be mountain wave activity that will contribute to localized stronger gusts near areas of higher terrain. These factors will make this winds more impactful than a typical event. The most persistent strong winds look to occur along the Rocky Mountain Front and the plains along and west of the I15 corridor where max gusts in the 75 to 90 mph range will be common. Most of the winds will occur in the daylight hours with the exception of Fergus County and areas near the Bear's Paw Mountains. These locations will see their strongest winds later in the afternoon and continuing well into the overnight hours.

Light mountain snow and lower elevation scattered rain and snow shower activity will develop on the backside of this system with a short period of below average temperatures following the cold frontal passage. Milder conditions move in for next weekend before another trough passes through heading into early next week. While this system should bring some cooler temperatures and increased shower activity, confidence is low in regards to precipitation coverage and amounts due to a large portion of the said trough shearing off and moving southeast toward the Great Basin and southwestern conus. - RCG

- Forecast Confidence & Scenarios:

Strong winds on Tuesday...

Confidence continues to increase for a compact mid- level low to bring a period of strong winds during the day on Tuesday. Any shifts in timing of the low level jet would result in the strongest winds being more localized. While there certainly have been faster jetstreams than the 60 to 70 kts this time around, a mid- day or afternoon passage greatly increases momentum transfer from higher levels compared to an overnight or early morning passage. Currently, the highest confidence for higher end 70 to 90 mph wind gusts are mostly along the Rocky Mountain Front and the plains west of I90. Winds decrease some and become more sporadic heading east and southeast.

Impacts will include difficult to dangerous travel conditions for high profile or light weight vehicles, localized visibility reductions from blowing dust, and instances of infrastructure/tree damage. Additionally, a brief period of elevated fire weather conditions may develop for central/southwestern areas roughly south of the US highway 12 corridor. The high wind watch was expanded to include much of central/north-central MT and portions of the southwest. I did leave out the Helena and Bozeman areas for now due to low confidence in criteria gusts lasting more than an hour or two. Most of the watches start Tuesday morning and in the evening. The only exception to this is for Fergus County and the Berar's Paw zones. These areas will see their peak winds starting later in the afternoon and persisting into the overnight hours. Wednesday may even be windy for these eastern areas, but held off extending the high wind watch beyond early Wednesday morning. - RCG

AVIATION

05/12Z TAF Period

A surface high over the Canadian prairies will bring easterly surface breezes for much of the forecast area through Monday. Winds may gust over 20 kts at times. Model guidance has been struggling with cloud cover over north- central MT, but low VFR/MVFR cloud cover will generally increase today and tonight, particularly along the Hi-Line. Some patchy fog or isolated areas of drizzle or light snow can't be ruled out either. - RCG

PRELIMINARY POINT TEMPS/POPS

GTF 51 29 56 40 / 10 10 10 10 CTB 45 27 53 37 / 20 10 10 0 HLN 59 35 62 38 / 0 0 10 0 BZN 62 32 61 34 / 0 0 10 10 WYS 55 25 57 25 / 0 0 10 10 DLN 63 35 64 37 / 0 0 0 0 HVR 45 27 51 32 / 30 10 0 10 LWT 51 28 48 34 / 10 10 10 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Watch from Tuesday morning through Tuesday 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 Watch from Tuesday morning through Tuesday evening for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Northwest Beaverhead County-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.

High Wind Watch from Tuesday afternoon through late Tuesday night for Bears Paw Mountains and Southern Blaine-Fergus County below 4500ft-Snowy and Judith Mountains.