Warmer temperatures and rain today could result in melting snow, rising waters on creeks and streams and ice jam flooding, the National Weather Service said.
The weather service issued a flood watch for Erie, Genesee and Wyoming counties along with the western Southern Tier from this afternoon to Friday afternoon.
"There is a risk for ice jam flooding starting Thursday afternoon, followed by a risk of general flooding Thursday night through Friday afternoon," the weather service said.
The weather service also issued a special weather statement cautioning motorists traveling along the Lake Erie shoreline near downtown Buffalo to be on the lookout for locally dense fog.
Forecasters said fog reduced visibility along stretches of the Niagara Thruway and Route 5 corridor between downtown Buffalo and Lackawanna.
"Watch for rapidly changing visibility conditions as you approach the Lake Erie shoreline," the weather service said.
Temperatures in Buffalo today are forecast to reach 50 degrees. Chances for rain increase this afternoon.
Rain is expected overnight with temperatures and dewpoints forecast to stay above the melting point.
Forecasters said models were struggling to agree on how much rainfall was expected.
"There is considerable uncertainty in rainfall amounts with totals most likely to be between a quarter and a half-inch, but may approach an inch in some locations," the weather service said.
Friday is expected to get cold again.
Forecasters said lingering precipitation is expected to change from rain to snow Friday morning.
Daytime highs in the mid-30s are forecast with lows back in the teens overnight, the weather service said.