Forecast Worsens Overnight, Snow Estimates Up For Eastern PA

While you were sleeping the forecast didn't get better. It got worse. A winter storm warning is now in effect from Tuesday evening into Thursday morning, with as much as 18 inches of snow now predicted during a "long duration" storm.

Forecasters are warning the two-wave storm will now have significant impacts, including 45 mph winds and the potential for power outages. The worst of the storm is expected on Wednesday, extending it to a 36-hour system.

Mixed precipitation is expected to start on Tuesday evening as sleet and freezing rain. Total wet snow and sleet accumulations of up to 2 inches on Tuesday with up to 1/10 of an inch of glaze possible, the NWS predicts.

But things get worse Wednesday, and commuters should plan on very difficult travel conditions in the afternoon, including during the evening commute on Wednesday. Snowfall rates of 1 to 3 inches per hour are expected and significant reductions in visibility are possible.

The winter storm warning ends Thursday morning at 2 a.m.

As of Tuesday morning, here is what is expected in terms of snow totals:

The National Weather Service is describing the storm as potentially "dangerous," saying it will threaten the region with heavy accumulations of wind-driven sleet and snow that will make travel very difficult at times.

Forecasters say it will be a heavy, wet snow that will be difficult to shovel and will stick to trees and power lines. Residents should be prepared for widespread power outages.

Those with flights into and out of the major Northeast hubs should be prepared for possible delays and cancellations at midweek, according to AccuWeather.

Here is the forecast:

Today: A slight chance of snow before 1pm, then rain and sleet, possibly mixed with snow. High near 36. East wind 10 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 80%. Total daytime snow and sleet accumulation of less than a half inch possible.

Tonight: Rain and sleet, possibly mixed with freezing rain before 11pm, then rain, possibly mixed with freezing rain between 11pm and 3am, then snow, possibly mixed with freezing rain after 3am. Low around 30. Northeast wind 14 to 17 mph. Chance of precipitation is 80%. Little or no ice accumulation expected. New snow and sleet accumulation of less than one inch possible.

Wednesday: Snow. The snow could be heavy at times. Some thunder is also possible. High near 33. Northeast wind 15 to 17 mph. Chance of precipitation is 100%. New snow accumulation of 6 to 10 inches possible.

Wednesday Night: Snow likely, mainly before 9pm. Cloudy, with a low around 29. North wind 13 to 15 mph. Chance of precipitation is 60%. New snow accumulation of 3 to 7 inches possible.

Thursday: Mostly sunny, with a high near 43. Northwest wind 11 to 13 mph.

Thursday Night: Partly cloudy, with a low around 27.

Friday: Mostly sunny, with a high near 43.

Friday Night: Mostly clear, with a low around 26.

Saturday: Mostly sunny, with a high near 44.

Saturday Night: A chance of rain and snow before 9pm, then a chance of snow. Mostly cloudy, with a low around 31. Chance of precipitation is 30%.

Image via NWS