DISCUSSION

Note: The forecast area for the National Weather Service Great Falls Weather Forecast Office includes north central, central and southwest Montana.

This Weekend...A closed upper level area of lower heights is located over the Canadian Saskatchewan Province. Upper level trofs rotating around the Saskatchewan closed low press southward over The Treasure State on their counter clockwise rotating path.
Daytime and nighttime temperatures are cooler than they have been of late, ranging closer to normal. Isolated afternoon and evening thunderstorms develop, each day, especially across southwest, and portions of central, Montana.

Monday...An upper level area of high heights builds across the southern U.S. and Mexico. With an upstream upper level trof approaching Montana, the upper level height gradient tightens and a windy and dry day is forecast.

Tuesday...The afore mentioned upper level trof enters our region.
Afternoon and evening thunderstorms and rain showers are forecast.

Wednesday through next Saturday...A strong upper level ridge dominates our region, with high confidence in a return to warmer temperatures. As of this time, the National Blend of Models (NBM)
shows a 75% to 95% chance of high temperatures greater than or equal to 90 degrees Fahrenheit, next Saturday, across most of our low elevation areas. With this so far in the extended forecast period, there is considerable uncertainty in reference to a temperature forecast, other than to share the previously mentioned high confidence in a return to above average temperatures, during this period. Winds are, generally, forecast light to breezy, with some gusts to around 30 mph along The Northern Rocky Mountain Front, at times. This period is, also, characterized by dry conditions.
- Fogleman

AVIATION
27/12Z TAF Period

Note: The NWS Great Falls Weather Forecast Office manages the following TAfs: KCTB, KHVR, KGTF, KLWT, KHLN, KBZN, KEKS and KWYS.

With the exception of KWYS, our airfields remain VFR throughout this TAF period. KWYS begins this TAF period in MVFR conditions due to low visibility in mist. From 27/16Z, KWYS returns to VFR conditions and maintains those conditions for the remainder of this TAF period.
- Fogleman

The immediate concern is the wildfire smoke moving over the area, which should persist through the period, especially over Central and Southwest Montana. It will likely cause at least some slantwise visibility restriction and some mountain obscuration. Surface visibility restriction will generally be minimal, staying at or above 6SM. However, some areas closer to fires and in valleys could have periods of MVFR visibility, such as the KHLN terminal area.
- Coulston

This afternoon and evening, thunderstorms are forecast to develop and impact southwest, and portions of central, Montana. PROB30s for thunderstorm are included in our southwest Montana TAFs.
- Fogleman

Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information.

FIRE WEATHER

This weekend's temperatures range closer to normal, with moderate overnight recovery. Today, there is a 20% to 30% chance for thunderstorms to develop across fire zone 118, with a slight (<20%) chance across the southeastern portion of zone 117. Sunday, there is a 25% to 35% chance for thunderstorms across the same zones. Monday is forecast windy and dry, with a return of thunderstorms on Tuesday.
- Fogleman

PRELIMINARY POINT TEMPS/POPS
GTF 86 53 83 54 / 0 10 10 0 CTB 83 48 84 52 / 0 0 0 0 HLN 90 57 87 56 / 10 20 20 10 BZN 89 51 83 50 / 30 30 40 10 WYS 77 42 73 39 / 30 40 60 10 DLN 83 48 80 47 / 40 40 30 10 HVR 87 53 90 56 / 0 0 10 10 LWT 83 53 81 52 / 10 20 40 10

TFX WATCHES/WARNINGS/ADVISORIES
None.