A winter weather advisory has been issued by the National Weather Service, in effect from 1 Wednesday afternoon until 6 a.m. Thursday. The advisory is for snow and ice throughout the northern portions of southwestern Connecticut. Driving conditions will be hazardous late today into early Thursday morning. Conditions will begin as light snow, mainly after 4 p.m. Accumulations of one to four inches of snow are expected along with ice. Winds will be from the east, 20 to 30 mph, with gusts up to 50 mph. Temperatures will be in the low 30s this afternoon through late tonight. Visibility can be one-quarter to one-half mile or less at times. The forecast indicates rain tonight before 8, alternating between snow, rain and sleet. Thursday will begin with rain, mainly before noon. A high of 45 is expected. It will be a little less windy, 13 to 17 mph, with gusts up to 33 mph.