Forecasters believe the Lehigh Valley could get up to 18 inches of snow this weekend in what could be the biggest snowstorm for the area in years.

The major winter storm will likely start late Saturday night or early Sunday morning during what is already a very cold period for the region and surrounding counties, according to the National Weather Service in Mount Holly, New Jersey. Initial predictions for the storm show 12-18 inches of snow falling through Monday.

The Lehigh Valley will be under a winter storm watch from 1 a.m. Sunday until 1 p.m. Monday. There could be some light ice accumulation during the storm.

The storm is coming during a very cold period of time, and single-digit lows are expected over the next several days. The region is under a cold weather advisory from 10 p.m. Friday until 10 a.m. Saturday. Monroe and Carbon counties are under an extreme cold warning during that time period, with wind chills of -20 degrees possible.

Wind chills in the Allentown area are expected to be mostly below zero through next Friday, according to forecasters.

The storm will begin coming from the southwest to the northeast, and because of the cold temperatures, precipitation should begin as all snow, meteorologists for the local weather service wrote Friday in their daily forecast discussion. 

By daybreak, snowfall could be moderate to heavy at times, they said. The storm, described as likely an all-snow event, will continue into Monday afternoon. Widespread closures are expected. Snow drifts and minor snow blowing, leading to reduced visibility, are also possible.

Forecasters said major impacts are likely, and travel will be either dangerous or impossible. The storm could also cause power outages.

A prolonged period of below-normal temperatures is expected to continue after the storm. Prolonged exposure to the dangerous wind chills could cause hypothermia or frostbite if precautions are not taken, forecasters warned. Any snow or ice-covered areas will be slow to melt over the coming days.

A number of municipalities in the Lehigh Valley, including Allentown, have announced snow emergencies ahead of the storm.

Friday AM Update: A major winter storm is still expected to impact the region Sat Night through Mon Morning. The primary change with this update is a slight reduction in snow totals across the Delmarva into southeastern NJ due to increasing sleet/freezing rain potential. (1/2) pic.twitter.com/OqV4a5QiHW

— NWS Mount Holly (@NWS_MountHolly) January 23, 2026

Here is the extended forecast from the National Weather Service:

Saturday: Partly sunny, with a high near 18. Wind chill values as low as -7. Northwest wind 5 to 10 mph.

Saturday night: Snow likely after 1 a.m. Cloudy, with a low around 12. Northeast wind around 5 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.

Sunday: Snow. The snow could be heavy at times. High near 20. East wind 10 to 15 mph. Chance of precipitation is 100%. New snow accumulation of 8 to 12 inches possible.

Sunday night: Snow. Low around 18. Chance of precipitation is 100%.

Monday: A chance of snow. Mostly cloudy, with a high near 26. Chance of precipitation is 50%.

Monday night: Partly cloudy, with a low around 4.

Tuesday: Mostly sunny, with a high near 18.

Tuesday night: Partly cloudy, with a low around 4.

Wednesday: Mostly sunny, with a high near 22.

Wednesday night: Mostly cloudy, with a low around 3.

Thursday: Partly sunny, with a high near 19.

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