If your Halloween costume includes an umbrella, you might want to hold on to it through the end of the week, National Weather Service forecasts show.
It's going to be wet.
Rain is expected today, Thursday and Friday, forecasts show.
"A cold front will move through Western New York Wednesday and stall near the New York/Pennsylvania border through Thursday night," the weather service said in a hazardous weather outlook. "Additional rainfall on an already saturated ground may push some rivers to flood stage."
The weather service posted a flood watch from 5 p.m. Thursday to 5 p.m. Friday for all of Western New York.
As much as 3 inches of rainfall is possible.
"This heavy rain will fall on already saturated soils," the weather service said. "Excessive runoff from heavy rainfall may result in minor flooding of poor drainage areas and small creeks."
It added: "Minor flooding is also possible on some of the larger creeks and rivers on Friday, including the upper Genesee River, upper Allegheny River, and Buffalo area creeks."
For metro Buffalo, up to three-quarters of an inch of rain is possible through tonight.
Another one-quarter to one-half inch is possible Thursday with up to an additional three-quarters of an inch Thursday night and an additional one-quarter of an inch of rain on Friday, forecasts show.
Before the arrival of the cold front, temperatures will remain warm -- in the mid to upper 50s today.
For normal trick-or-treating hours, between say 3:30 and 8 p.m., the weather service says you can expect temperatures in the low to mid 50s with cloudy skies and generally a 25 to 50 percent chance for showers, decreasing into the early evening.
Chances for showers increase again overnight tonight. There's an 80 percent chance for rain Thursday and it won't be as warm. Temperatures will top out in the upper 40s, near 50 degrees, the weather service said.
Rain could get heavy, at times, overnight Thursday. It's expected to continue into Friday, which will be a little bit warmer with temperatures in the mid 50s.
"There is the potential for widespread 1-2 inches of rain from Wednesday night through early Friday," the weather service said. "The rain should be spread across a long enough time period to mitigate any short fused flash flooding issues. However, the likelihood of small stream/creek flooding seems to be increasing and will need to be monitored closely."
It added: "Even headwaters and a few main stem rivers may reach bank-full during this time."