The GFS mode is indicating that the potential for snowfall on October 19th is less likely than earlier anticipated. See the below image for precipitation type forecasts: BLUE is RAIN, PINK is SNOW.
So here's the set-up: A low pressure system will swing across the nation's midsection and then curl up through New York into Canada. This low will bring with it a very cold air mass behind it, creating what at one time appeared to be the potential for snowfall. However, at this time, it looks like any precipitation that previously appeared possible is no longer forecast to be in the vicinity. While freezing levels (the level in the atmosphere where the temperature falls below 32 degrees Fahrenheit) may be conductive for snowfall at some other time, it looks like the precipitation will mainly be rain.