PITTSBURGH (WPXI)— A Winter Weather Advisory expired at 4 a.m. Sunday due to the threat of freezing rain and freezing fog. A light glaze of ice will be possible on untreated surfaces. A Winter Storm Watch will go into effect at 1 a.m. Monday and continue until 1 p.m. Tuesday for Pittsburgh and points north and west, including Washington County. Two rounds of precipitation are expected. The first wave of snow will develop early Monday morning before sunrise, bringing the threat of a trace to three inches of snow. The lesser amounts will be across Fayette County and the higher amounts will be across our northwest counties. The second wave, which could include a bit of freezing rain, rain or sleet south of I-70 will move in Monday evening into Tuesday. This is where we look to pick up the bulk of our snow accumulation.