Area Forecast Discussion

KEY MESSAGES

- A few showers and thunderstorms early this evening in the Chinook area.

- Additional showers and perhaps a few thunderstorms Friday afternoon and evening with a cold front.

- Cooler temperatures remain into the weekend, but trend warmer early next week as ridging builds in.

UPDATE

Current forecast is on track, no evening update planned for this evening. Light showers/isolated thunderstorms continue to affect areas mainly along/north of Highway 2 from Havre to Harlem this evening. These storms continue to move southeastward through this area, with most of the storms diminishing around Midnight.

On Friday, the next round of showers/thunderstorms moves southward into North Central MT by late Friday morning, with the precipitation moving southward through North Central MT during the afternoon/early evening hours. No severe storms are expected at this time, but there is just enough instability that a few thunderstorms will be possible. This precipitation will likely move into Southwest MT during the evening hours on Friday.

Looking ahead, still looking like with could have a frosty Sunday morning, but warmer afternoon temperatures are expected for the first part of next week. Brusda

DISCUSSION

- Meteorological Overview:

Northwesterly flow aloft continues across the region in wake of the departing upper level troughing. Sufficiently cool air aloft will combine with daytime heating to result in a few showers and thunderstorms over the plains, most focused over the Hi-Line east of I-15. While gusty winds will be a concern with the strongest thunderstorms, the overall environment is no conducive to strong thunderstorms.

Troughing then begins to work southward out of Canada Friday, which will result in some afternoon showers and thunderstorms along and near a cold front. This activity persists into the overnight while slowly progressing southward over the region.

Upper level ridging slowly build sin from the west later this weekend. A few chilly mornings look to be in store through the weekend before temperatures trend warmer early next week as the ridge shifts eastward. A wave looks to flatten the ridge toward the middle of next week, which will result in increased shower and thunderstorm activity, along with breezy winds. -AM

- Forecast Confidence & Scenarios:

Guidance is still a bit split on exact timing of the progression of the front from north to south. The more aggressive guidance moves the front over the plains late morning and early afternoon, which would trend toward a lower probability for thunderstorms. Guidance that is slower with the progression moves it through later afternoon, which would allow for greater instability to develop ahead of the front. Stronger thunderstorms would be favored in this scenario.

Sunday morning still looks to be the coolest ahead of the building ridge. Clearing skies should allow most areas to drop into the 30s, with cold prone areas getting closer to 30. Given how short the nights are at this time of the year, the duration of any frost or freeze looks to be short lived Sunday morning. -AM

AVIATION

12/00Z TAF Period

A few light showers will affect areas around Chinook early this evening. Otherwise, expect winds to diminish and some clearing of skies this evening. Clouds increase once again on Fri morning, with a band of showers/thunderstorms to move southward through North Central MT late Fri morning through Fri afternoon. Kept thunder out of the TAF sites for now, but lightning will be around on Fri afternoon. Mountains/passes will become obscured over North Central MT on Fri afternoon. Brusda

PRELIMINARY POINT TEMPS/POPS

TFX WATCHES / WARNINGS / ADVISORIES

None.