textproduct: Great Falls

KEY MESSAGES

- Benign this weekend, but still on the cooler side.

- Winds and temperatures trend upward late weekend into early next week.

- Precipitation along the Continental Divide increases Monday and persists through much of the week.

- Impactful winds increasing in likelihood toward the middle of next week.

DISCUSSION

- Meteorological Overview:

Through Sunday:

The last embedded wave within broad troughing is moving across the region this afternoon, resulting in scattered snow showers across Central and Southwest Montana. This activity, along with a more stratiform type of snow further north, moves eastward tonight as associated broad upper level troughing shifts toward the central US.

Ridging builds in for the weekend, allowing for a benign period to develop. Though this is the case, a lack of any downsloping winds will keep much of the plains on the cooler side of average.

Monday onward:

The upper level ridging shifts toward the central US heading into early next week, which will allow for a more potent mid-level flow to develop at times. Initially this will bring increased winds and temperatures Monday to most areas. There is concern for blowing/drifting snow along the eastern slopes of the Rocky Mountain Front Monday morning at the onset of the winds, before the snowpack will be able to warm much and crust up as a result. This window appears narrow, as temperatures by the afternoon in these areas will get into the upper 30s to lower 40s. Elsewhere at lower elevations temperatures rise well above average once again beginning Monday, persisting through much of the week.

Given the zonal flow and Pacific moisture, most precipitation next week looks to fall along the Continental Divide. There looks to be some instability Tuesday which will aid in more precipitation making inroads across the Continental Divide. Dependent on how warm surface temperatures get, there will be at least a low-end risk for intense snow showers Tuesday across SW MT and vicinity.

Winds take another step stronger across most areas Wednesday, with both Thursday and Friday also appearing quite windy. -AM

- Forecast Confidence & Scenarios:

Winds next week:

To give some perspective of how windy it is looking next week, the probability of reaching high wind criteria for gusts (58 mph) at Cut Bank is as follows: Tuesday - 40%, Wednesday - 65%, Thursday - 70%, Friday - 60%. While winds look to be mostly over the plains early in the week, they look to make better inroads into Central and Southwest Montana valleys later in the week. -AM

AVIATION

20/18Z TAF Period

Initial concern will be for a more stratiform type of snow across North-central Montana through the afternoon, with a more showery type of snow across Central and Southwest Montana. Once these features slide eastward this evening and tonight, the only concern will be for some patchy fog toward Saturday morning, should areas clear out sufficiently. Confidence in fog was too low to warrant mention in any TAF at this time. Mountains will be obscured at times through the day today. -AM

PRELIMINARY POINT TEMPS/POPS

GTF -1 19 0 29 / 0 0 0 0 CTB -4 18 0 23 / 0 0 0 0 HLN 10 34 12 42 / 10 0 0 0 BZN 6 37 12 45 / 20 0 0 0 WYS -3 25 0 35 / 30 10 0 0 DLN 7 35 17 43 / 0 0 0 0 HVR -9 16 1 24 / 10 0 0 0 LWT 4 28 8 38 / 40 10 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.