textproduct: Great Falls

KEY MESSAGES

- Strong thunderstorms possible multiple days this week through Wednesday. - Additionally, heavy rains will be possible Monday night and early Tuesday morning, especially across the plains. - Generally drier second half of the week.

DISCUSSION

/Issued 330 AM MDT Sun Jul 5 2026/

Active weather is expected over the next few days as we remain in the meteorological ring of fire on the northern side of an upper level ridge to our south.

Upper level flow today will remain out of the southwest today ahead of a shortwave trough that will push through the area this afternoon and evening. As this trough swings through, showers and thunderstorms will begin to develop across Southwestern Montana, where instability will be highest. While instability will be maximized here, shear (which helps storms organize and sustain themselves), will be rather low, so these storms are likely to be rather pulse-driven. That said, given very deep inverted-V mixed layers and tall, skinny instability profiles, these storms may still produce some isolated gusty winds and localized downpours. Further north, shear will be a bit better, but instability will be rather minimal, keeping thunderstorms at bay.

Monday will see another, more energetic, upper level shortwave move from Northern Nevada into Western Montana. While this shortwave will arrive later in the day, showers and storms associated with this system will form in Central Idaho and move northeastward into Southwestern Montana in the late afternoon, and into North Central Montana during the evening hours. This convection is likely to tap into some elevated instability and shear, which will help it to persist well into the overnight hours. Atmospheric profiles indicate that heavy rain is possible, which could result in some flooding concerns if storms repeatedly traverse the same areas.

Yet another upper level system will push through the area on Wednesday, which will bring another round of showers and thunderstorms to the area. Models continue to show quite high instability over the plains, though the core of the instability seems to have shifted further north into Canada at the moment. That said, shear profiles, along with a forcing mechanism, still indicate that some strong wind gusts remain possible as a mesoscale convective system may attempt to develop over the Central Montana plains and move eastward.

Beyond Wednesday, upper level flow will be a bit more stable Thursday before the upper level ridge to our south begins to rapidly strengthen. This will keep our weather a bit quieter, but temperatures will begin to rise as we head into the end of this week. This ridge will then likely park itself to our south, which will result in a potential period of very warm to hot temperatures next week. Ludwig

AVIATION

05/12 TAF Period

While VFR conditions are expected to be the prevailing weather type over the next 24 hours, some TSRA are expected to develop across SW MT after 19z. Gusty winds and localized heavy downpours are possible at KBZN, KEKS, KHLN, and KLWT. Ludwig

PRELIMINARY POINT TEMPS/POPS

GTF 85 54 77 56 / 0 10 10 60 CTB 80 48 74 54 / 0 0 0 30 HLN 87 56 79 58 / 20 30 30 70 BZN 89 54 82 54 / 40 30 20 60 WYS 85 48 80 48 / 0 10 20 40 DLN 87 53 80 51 / 30 20 40 60 HVR 86 53 81 57 / 0 10 0 70 LWT 85 50 77 52 / 20 60 0 70

TFX WATCHES/WARNINGS/ADVISORIES

None.