textproduct: Great Falls

KEY MESSAGES

- Slight chance for afternoon showers and thunderstorms this afternoon across much of the region.

- More widespread precipitation is expected on Wednesday through Thursday.

- Temperatures will gradually warm through the week with the warmest temperatures expected this weekend.

DISCUSSION

/Issued 1226 AM MDT Tue May 19 2026/

- Meteorological Overview

After a cool start to the morning, temperatures will warm modestly into the 50s and 60s. Lingering moisture on the backside of the upper-level trough combined with modest instability will allow for pop-up showers and thunderstorms through the afternoon today.

On Wednesday another upper-level trough will arrive bringing a chance for widespread wetting precipitation to the region. Snow will be generally confined to locations above 7,000 feet with the rest of the lower elevations seeing primarily rain through the event.

As the upper-level trough starts to slowly exit the area towards the end of the week, temperatures will gradually start to warm up as upper-level ridging begins building over the western CONUS through the weekend.

- Forecast Confidence & Scenarios:

For today, hi-res models were showing pretty scattered 15-30% chances for precipitation across the region. In general, most locations will remain dry throughout the day except for where these pop-up showers end up developing. The highest chances for thunderstorm activity will be across North-Central Montana with any precipitation in Central and Southwest Montana expected to be more stratiform in nature.

There is still good agreement for widespread wetting rains. The heaviest amounts are currently expected along a stretch from the Northern Rockies down through Central Montana including Great Falls and Helena into Lewistown. Probabilities of more than 0.25" of precipitation are currently sitting at 60-80% with a 20-40% chance of 0.5" or more. While precipitation amounts across the remainder of North-Central and Southwest Montana are not expected to be quite as high there is still at least a 40% chance for a tenth of an inch or

AVIATION

19/12Z TAF Period

VFR conditions will prevail throughout the duration of the 1912/2012 TAF period; however, widely scattered showers and isolated thunderstorms will develop between 16-19z and persist through 03-06z Wednesday across Southwest through North Central Montana. Main impact from any shower or storm will be erratic winds and brief reductions in CIGS to low-VFR, along with mountain obscuration. - Moldan

PRELIMINARY POINT TEMPS/POPS

GTF 64 40 58 38 / 40 20 80 70 CTB 62 38 55 34 / 20 10 80 40 HLN 65 38 64 38 / 20 20 60 90 BZN 62 34 63 35 / 10 20 40 90 WYS 54 26 57 30 / 10 10 40 80 DLN 61 34 62 35 / 10 20 20 70 HVR 68 40 62 36 / 30 30 50 10 LWT 60 36 58 35 / 30 20 80 80

TFX WATCHES/WARNINGS/ADVISORIES

None.