textproduct: Great Falls

KEY MESSAGES

-It remains cool today with a rapid warm up to end the work week.

-Winds will increase on Friday and Saturday.

-It will be dry this week.

DISCUSSION

/Issued 1247 AM MDT Tue Aug 4 2026/

- Meteorological Overview:

Today there is zonal flow over North-central, Central, and Southwestern Montana. This will allow temperatures to warm up a few degrees with dry weather. On Wednesday an upper-level ridge begins to build in over North-central, Central, and Southwestern Montana. This will allow temperatures to warm up some more with dry weather. On Thursday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will allow temperatures to warm back up to well-above seasonal averages. On Wednesday and Thursday with the increasing temperatures the minimum relative humidity will drop into the teens each afternoon.

On Friday the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will allow temperatures to warm up further and be well-above seasonal averages. Friday afternoon/evening the upper-level ridge begins to break down. This combined with strong low-level and mid-level winds will bring windy conditions to the area. Afternoon relative humidity will drop into the low teens as well. For more details see the Forecast Confidence & Scenarios section. On Saturday upper-level zonal flow is in place over North-central, Central, and Southwestern Montana. This will keep warm but slightly cooler temperates over the area. Due to strong mid-level and low-level winds lingering over the area it will remain windy on Saturday. On Sunday and Monday there will be northwest flow aloft which will cool things down slightly to be closer to seasonal averages. It will be mostly dry on Sunday and Monday. -IG

- Forecast Confidence & Scenarios:

Friday through Saturday there is a 30 - 60% chance for wind gusts of 30 mph or greater across North-central, Central, and Southwestern Montana. On Friday and Saturday there is a 30 - 50% chance for relative humidity of 20% or lower and wind speeds of 15 mph or greater across North-central, Central, and Southwestern Montana. Clusters and deterministic models are in good agreement that Friday afternoon/evening the upper-level ridge will break down and bring gusty winds to the area on Friday and Saturday. This combined with critically low relative humidity will lead to at least near critical fire weather conditions on Friday and Saturday. Currently deterministic models and ensembles differ on the placement and timing of the strongest upper-level winds and the upper-level ridge breakdown. This affects both how low the relative humidity gets and the strength of the surface winds.

On Friday there is greater than a 50% chance for high temperatures of 95 degrees or greater across most of the North-central Montana plans east of I-15. -IG

AVIATION

04/12Z TAF Period

Regional wildfire smoke will result in localized reduction to visibility across Southwest Montana today. Confidence in this reduction being to sub-VFR levels was too low to warrant mention in TAFs at this time, however. Light winds prevail today under just a few clouds.

For KGTF: No concerns over the next 24 hours. Light and variable winds through the day today will yield a probability for a 15 kt cross wind of essentially zero. -AM

PRELIMINARY POINT TEMPS/POPS

GTF 77 49 86 52 / 0 0 0 0 CTB 75 47 82 50 / 0 0 0 0 HLN 78 48 86 51 / 0 0 0 0 BZN 78 46 84 49 / 0 0 0 0 WYS 75 35 80 38 / 0 0 0 0 DLN 76 45 83 48 / 0 0 0 0 HVR 79 48 86 51 / 0 0 0 0 LWT 72 46 81 50 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.