Glasgow, Montana

• Patchy fog continues through tomorrow morning.
• Light rain spreads north in the afternoon, continuing into trick or treating hours.
• Widespread precipitation begin on Monday as a frontal system moves across the region.

Upper ridge over the northern plains will slowly drift eastward through the weekend as an upper trough digs into the western states. Southwest flow and weak embedded shortwaves will bring periodic chances for rain into the region.

Light rain will continue to slowly move northeast through the evening and linger overnight. Most locations look to have a damp and chilly Halloween evening. Fog will continue to impact portions of the region through the morning with some locally dense fog, reducing visibility in spots to 2 mile or less.

As the Pacific upper trough moves through the Great Basin, a Colorado low is expected to develop ahead of it. This will spread precipitation northward, and will generally favor the Yellowstone basin for Sunday night into Monday. Splitting in the upper trough near the Canadian boarder will keep cold air from being drawn southward, and result in little to no mixed precipitation or snow. As the surface low deepens, an increase in winds will result by Monday afternoon.

A progressive, unsettled pattern will keep next week interesting with repeated upper level troughs.

FORECAST CONFIDENCE & DEVIATIONS

Adjusted PoPs by blending SREF for slightly expanded coverage. Otherwise no changes to NBM.

A lot of uncertainty regarding fog, low cloud and precipitation today.

System for Monday continues to slide southward, which is common, and could result in less precipitation, especially across the north, than expected.

LAST UPDATED: 1900Z

FLIGHT CAT RANGE: MVFR, IFR during patchy fog.

DISCUSSION: Lingering MVFR/IFR stratus will continue through tomorrow. Low stratus and patchy fog cannot be ruled out again overnight. Light rain at times through the late evening. Widespread rain begins after 0z Monday.

WIND: Light and variable through tomorrow afternoon.

None.