Buffalo (BUF) — the National Weather Service forecast in plain English · Plaincast

What has changed

Minor changes to the forecast with this update.

Messages

Colder air will be accompanied by scattered wet snow and rain showers through this weekend with minor snow accumulations expected across the higher terrain.

Dry weather will return by Monday, with temperatures trending warmer by midweek.

Discussion

KEY MESSAGE 1. Colder air will be accompanied by scattered wet snow and rain showers through this weekend with minor snow accumulations expected across the higher terrain.

The low-level flow will slowly back tonight as a surface low moves off the east coast. An area of frontogenesis aloft exists north of the surface low, with associated focused areas of precipitation primarily east of our forecast area as of 12:30 AM EST Friday. A shortwave trough will move across the region tonight, with moisture pulling away from the region. The atmospheric column will continue to cool via CAA at the surface and aloft, the wet-bulb effect, and nighttime cooling so that any lingering rain across the Western Southern Tier, Finger Lakes, and North-Central NY will change to wet snow overnight. Lake-induced and upslope flow-induced snow showers will develop generally south of the eastern Great Lakes late tonight. A coating of wet snow accumulation is possible by daybreak Friday, especially along higher terrain such as the Chautauqua Ridge and hills of the Finger Lakes Region.

The set-up will become favorable for upslope flow-induced and lake- effect precipitation Friday through Friday night generally south of the eastern Great Lakes. However, a lack of synoptic moisture should prevent the formation of any organized precipitation. Cold air advection and low atmospheric melting levels will support rain mixing with or changing to wet snow at times at lower elevations and primarily wet snow at higher elevations. Very little or no snow accumulation is expected at lower elevations, but additional snow accumulations of a coating to 2" are expected along the Chautauqua Ridge and Bristol Hills.

A sharp mid/upper-level trough axis is expected to approach and then swing south-southeastward through our region Saturday through Saturday night. This will support an uptick in precipitation across Western and Central NY, however this uptick should be fairly short- lived. A quick coating of snow accumulation is possible at lower elevations, while an additional coating to 1" of snow accumulation is expected at higher elevations of Western NY, the Finger Lakes Region, and North-Central NY, including the Tug Hill Plateau.

High pressure at the surface and aloft builds from the west on Sunday through Sunday night, while subtle shortwave trough axes embedded in the northerly mid/upper-level flow traverse Western and Central NY. Much drier air behind Saturday night's mid/upper-level trough axis passage will expand through the dendritic snow growth zone Sunday morning, with any lingering upslope flow-induced and lake-induced wet snow and/or rain showers amidst north-northwesterly mean low-level flow ending through the morning hours. A few wet snow and/or rain showers may linger across Central NY into the early afternoon hours. The still cool northwesterly to north-northwesterly mean low-level flow and shallow low-level moisture on the synoptic- scale will maintain a wealth of upslope flow-induced and lake-effect cloud cover through the afternoon and overnight time period.

KEY MESSAGE 2. Dry weather will return by Monday, with temperatures trending warmer by midweek.