textproduct: Great Falls

KEY MESSAGES

- Seasonable temperatures today and tomorrow, with a brief warm up through this weekend.

- Generally dry through next week, with light rain showers dissipating this evening.

DISCUSSION

/Issued 1224 PM MDT Wed Sep 30 2026/

- Meteorological Overview:

Zonal flow aloft will continue throughout today, before weak ridging begins to build off to the west tomorrow. This will allow temperatures to remain seasonable today and tomorrow, with highs in the mid 60s to low 70s across much of the CWA. Some areas north of the Hi-Line will see cooler highs in the mid 50s. Light rain showers will continue across Central/North-Central MT through this afternoon, dissipating as the evening approaches.

Friday presents a similar situation, with weak ridging aloft allowing temperatures to continue to warm to highs in the 70s. A weak shortwave will move through Saturday, causing a brief cooldown in temperatures, before stronger ridging aloft builds on Sunday. The upper level high pressure on Sunday and Monday will cause temperatures to rise, before an upper level trough moves in lowering temperatures back down to seasonably normal by the middle of next week.

- Forecast Confidence & Scenarios:

The weather will be generally mild throughout the forecast period. However, there is the potential for fire weather concerns on Monday. High temperatures in the 70s to mid 80s, minimum RH values in the teens to mid 20s, and winds gusting 20-30 mph are expected. While at the moment nothing appears critical, we will be keeping an eye on how these conditions progress. -Dzomba

AVIATION

01/00Z TAF Period

Isolated rain showers currently between KHLN and KLWT are expected to dissipate by 02Z. Conditions throughout the region will be predominantly VFR however temporary IFR conditions are expected at KWYS from 09Z to 13Z due to fog/mist and low stratus that could develop as the temperature cools to the dewpoint. Persistent scattered or more cloud cover would prevent any fog formation though. Winds should remain relatively light throughout the period with mid- level cloud cover over most terminals. Icing in cloud above FL060 could also be present over KGTF, KLWT, KCTB, and KHVR terminal areas. - Akins

PRELIMINARY POINT TEMPS/POPS

GTF 43 63 44 77 / 20 0 0 0 CTB 36 59 37 70 / 0 0 0 0 HLN 43 67 41 75 / 0 0 0 0 BZN 40 67 39 75 / 0 0 0 0 WYS 30 67 32 68 / 0 0 0 0 DLN 40 70 41 76 / 0 0 0 0 HVR 38 63 36 73 / 0 10 0 0 LWT 41 61 40 75 / 20 20 10 0

TFX WATCHES/WARNINGS/ADVISORIES

None.