textproduct: Great Falls

KEY MESSAGES

- High winds will lead to dangerous travel, especially for high profile vehicles, and backcountry recreation along the Rocky Mountain Front and portions of the Hi-Line through this evening.

- Temperatures will fluctuate over the next few days ranging between near normal on Sunday and Tuesday to around 10 degrees above normal on Monday and Wednesday.

- Overall dry conditions are expected through Monday, with low chances for precipitation arriving on Tuesday across Southwest and Central Montana.

DISCUSSION

- Meteorological Overview:

Upper level ridging over the Western CONUS early this morning will continue to be flattened as a potent shortwave over the Gulf of Alaska slides east over British Columbia and the Canadian Prairie Provinces through the day today. Increasing cross barrier flow over the Northern Rockies will lead to strengthening southwest to west winds across Southwest through North Central Montana, most notably along the Rocky Mountain Front and International Border. These downsloping southwest to west winds will lead to another day of above normal temperatures across the region, with highs peaking in the mid-60s to near 70 degrees in the valleys of Southwest and Central Montana to the low 70s to near 80 degrees over the plains of Central and North Central Montana. "Cooler" temperatures are then expected into the day on Sunday in wake of a weak Pacific front, which will slide east and over the Northern Rockies late tonight, with highs topping out in the upper 50s to low 60s. Despite persistent zonal flow over the Northern Rockies on Sunday weak surface high pressure settling in over the Pacific Northwest and Northern Rockies will help to support light surfaces winds and continued dry conditions. - Moldan

Through next week split flow will set up with an upper-level low centered off the coast of California. This setup will put Montana under southwesterly flow with moisture being funnel into Southwest Montana for daily precipitation chances. The forecast uncertainty increases significantly towards late next week with some hints that an upper-level trough could move south and merge with the low as it moves off to the northeast. This could bring more widespread chances for precipitation and some cooler temperatures although there is still a bit of disagreement on what exactly this means for our area. -thor

- Forecast Confidence & Scenarios:

Gusty to strong winds will continue across Central and North- Central Montana through the rest of the afternoon and evening hours. The strongest winds will be more confined to the Rocky Mountain Front where sustained winds of 40 to 50 mph and gusts up to 85 mph are possible.

While frequent gusts in the 40s are occurring across the Northern Plains and a gust up to 50 mph has been observed in Great Falls, there is still low confidence in wind speeds/gusts reaching full high wind criteria. As a result, no expansion was made to the High Wind Warning with this forecast.

Winds will start to taper off towards sunset into the overnight hours. Periods of gusty winds may still continue for a little while but generally the worst of the winds are expected to be done by 8 PM. -thor

AVIATION

17/18Z TAF Period

Breezy to gusty west to southwest winds continue to develop this afternoon across North-Central MT and KEKS, with the highest wind speeds possible over the Rocky Mountain Front. Higher end gusts can reach near 50kts at times at KCTB. Winds decreases in the evening between 18/03z to 18/06z before becoming light through the rest of the TAF period. Mountain wave activity persists through the rest of the evening. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 42 60 39 69 / 0 0 0 0 CTB 36 57 32 60 / 0 0 0 0 HLN 37 62 35 67 / 0 0 0 0 BZN 34 60 32 66 / 0 0 0 0 WYS 23 57 22 58 / 0 0 0 0 DLN 33 61 33 64 / 0 0 0 0 HVR 38 62 35 65 / 0 0 0 0 LWT 40 57 37 71 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until midnight MDT tonight for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Eastern Toole and Liberty-Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.