WEATHER ALERT: Bryn Mawr's Hour-by-Hour Forecast of 'Long-Duration' Snow

We’ve already got a lot of snow, and we’re going to get more.

Snow will continue falling through Thursday afternoon, and will be heavy, the National Weather Service said. “Widespread and substantial impacts on travel are expected,” the NWS said.

PennDOT said it urges motorists to avoid unnecessary travel, and has reduced speed limits to 45 mph on several expressways in the Philadelphia region, including:

• Interstates 76, 95, 476, 676
• U.S. Routes 1, 30, 202, 422
• State Routes 63, 100 Spur and 309.

Snow will likely keep falling in Bryn Mawr until 7 p.m. Thursday, the National Weather Service said. Expect temperatures below zero overnight as winds pick up.

Here’s the hour-by-hour forecast, according to the National Weather Service:

• Thursday: Snow, mainly before 5 p.m. Steady temperature around 24. North wind 10 to 13 mph. Chance of precipitation is 90 percent. Total daytime snow accumulation of 3 to 5 inches possible.
• Thursday night: A chance of snow, mainly before 7 p.m. Mostly cloudy, then gradually becoming mostly clear, with a low around 5. Wind chill values as low as -3. North wind 6 to 9 mph. Chance of precipitation is 30 percent. New snow accumulation of less than a half inch possible.
• Friday: Sunny, with a high near 25. Wind chill values as low as -6. North wind around 6 mph becoming light and variable in the afternoon.
• Friday night: Mostly clear, with a low around 9. Calm wind becoming west around 5 mph.