Unseasonably warm temperatures and dry conditions are expected across Western New York through at least sunset before a surge of moisture associated with a pair of storm systems brings rain across the region, the National Weather Service said.
The mercury should make it into the upper 40s to near 50 degrees today under mostly cloudy skies.
Chances for rain are forecast to start in Buffalo by 7 p.m. and become likely by about 9 p.m., forecasts show.
Moderate to heavy rain is forecast overnight.
Periods of soaking rain will move across the region tonight through Friday night," the weather service said in its hazardous weather outlook for all of Western New York.
It added: "The first batch of rain tonight will produce around an inch of rainfall on average, with the second round of rain late Friday and Friday night producing another half inch on average."
Forecasters said that although runoff from the moderate to heavy rain is expected to produce ponding in poor drainage areas, and higher levels on creeks and streams, no significant flooding is forecast.
Overnight temperatures are expected to hover around 40 degrees.
Rain remains in the forecast Friday and Friday night, forecasters said. Temperatures are forecast in the mid 40s on Friday.
As temperatures begin to drop overnight Friday, precipitation is forecast to transition from rain to a mix of rain and snow around midnight and then all snow early Saturday morning.
Snow showers remain possible through the weekend with high temperatures expected in the low to mid 30s, the weather service said.
For now, the weather service has assigned a 30 percent chance for some show showers in metro Buffalo on Tuesday, Christmas Day, with highs in the mid 30s.
Any significant snowfall, or suggestions of a wintry white landscape for Christmas is unlikely, forecasters said.