Billings (BYZ) — the National Weather Service forecast in plain English · Plaincast

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Near seasonable temperatures (highs in the 40s and 50s) this weekend into next week.

Unsettled conditions (20-50% precipitation chances) late Sunday into next week. Uncertainty is high for the extended forecast.

Update

Early morning satellite imagery shows drier WNW flow spreading through MT in the wake of yesterday's weather system, and a low cutting off over the southern great basin. Cloud cover exists over the east half of our cwa but expect mostly clear skies everywhere by sunrise. As temperatures fall toward 20F in the west cannot rule out localized fog early. This may include Livingston.

Cooler and unsettled weather continues for the next few days and here are a few items of note and worth monitoring. (1) Models are coming more in line showing the SW low lifting far enough north to bring some light precipitation to far southeast MT late Sunday into Monday. Boundary layer may be cold enough (w/ easterly winds) for a mix with wet snow over the highest hills, such as those around Ekalaka. At the very least it looks like we will have low clouds/fog to deal with early next week, again w/ persistent easterly flow, not only in the east but also perhaps along western foothills. (2) Next Pacific wave reaches south central MT late Monday night bringing a good chance of showers through the west into Tuesday. Steep lapse rates and colder mid levels suggest accumulating snow over favored SW-NW aspects of the Beartooth- Absaroka and Crazy mountains. Look for 2-5" of accumulation with a 20% chance of exceeding 5". (3) As the Tuesday shortwave tracks eastward it is possible that higher hills of southeast MT see some wet snow.

Discussion

The current weather system exits this morning, ending the current chance for precipitation and allowing for mostly clear skies into early Sunday. Breezy winds will linger longest over the east but are expected to decrease by early this afternoon. Highs will be much cooler this weekend, in the 40s to low 50s.

Late Sunday into Monday, an upper low clips southeast Montana, allowing for a chance (20-50%) of light showers over the southeast. As temperatures decrease overnight, rain will change over to snow, although little to no snow accumulation is expected. Currently, there is a less than 20% chance for more than a 0.1" of snow outside of the higher hills.

Late Monday into Wednesday, a more impactful system is expected to bring a better chance (30-50% over the plains, 60-80% over the mountains) for widespread precipitation. Highs will remain in the 40s to low 50s. While the exact timing and intensity of this system remains uncertain, models are continuing to come into better agreement, and there is currently a 20-50% chance of more than 0.25" of rain and snow water content over the plains, highest over south central Montana. During the overnight hours, when lows are in the 20s to low 30s, some of this precipitation may fall as snow over the plains. Currently, there is a 10-30% chance for at least 0.1" of snow over the plains. Above 7,000 ft, there is a 40-60% chance for at least 4" of snow.

For the end of the work week, upper level southwest flow sets up, allowing for occasional rounds of precipitation to continue. Archer