Warm, springlike air Thursday will rapidly melt the snow pack, create substantial water runoff and initiate ice jam flooding on area creeks and streams.
The National Weather Service posted a flood watch for all of Western New York from Thursday through Friday night.
"Snow melt and warming temperatures Wednesday will soften river ice," the weather service said.
Today's high is expected to reach into the low to mid-40s. The day will start with partly sunny skies, but rain is expected to start by late afternoon.
Showers are also likely this evening and the mercury will stay up there — in the low 40s overnight.
"Ice jams will follow thereafter, Thursday through Friday night," the weather service said. "Buffalo, Cayuga, Cazenovia and Cattaraugus creeks are traditionally the most susceptible to ice jam flooding."
The real warmup comes on Thursday with highs in the mid-50s expected with showers. More rain is forecast Thursday night with lows in the upper 40s.
"There is plenty of ice in place on area creeks and rivers, and the primary risk for flooding will be from ice jams," the weather service said. "People living in areas that are prone to ice jam flooding should take the time in advance to prepare for the potential for flooding this Thursday and Friday."
Crews from Buffalo were out on Cazenovia Creek Tuesday, cutting triangles through the ice to help it break up during the impending thaw and alleviate the possibility for significant ice jam flooding.
The weather service said a flood watch means a potential for flooding exists based on forecasts.
— David Church (@warmbias) January 10, 2018
A weather service statement Wednesday showed there was still significant snow pack across many areas of Western New York, including nearly 2 feet near Springville.
Total rainfall is forecast to be up to a half-inch during the course of the flood watch, forecasters said.
On Friday, a cold front is expected to move through.
Temperatures will drop from the low 50s at dawn down into the upper 20s by evening.
Rain will transition to a wintry mix of sleet, freezing rain and then snow, forecasters said.
And, forecasters said significant snow is likely later Friday into Saturday, replacing all the snow, and then some, that was lost during the brief thaw.
Early forecast models suggest a foot or more snow is possible across a wide swath of Western New York.
Another frigid weekend is expected.
Forecasts are calling for highs in the teens and lows in the single digits again.
Cold conditions are forecast to persist into early next week.