Snow and ice forecasts continue to shift for major winter storm that will hit New Jersey starting tonight, with a surging threat of significant icing and power outages for parts of the state.

“There is high confidence in major impacts from snowfall, sleet, and ice accumulations across much of the area, making travel very difficult, and potentially resulting in widespread closures and infrastructure impacts,” the National Weather Service said early Saturday. “Travel could be nearly impossible.”

Snowfall total forecasts for the southern half of the state have been lowered slightly due to more mixing with sleet and freezing rain Sunday afternoon.

But forecasters cautioned that means more dangerous ice in addition to snowfall and potential power outages.

“There is an increasing threat for impactful ice accumulations, on top of the heavy snow that falls tonight and tomorrow morning,” the weather service said. “Ice/sleet on top of snow will result in VERY hazardous travel conditions.”

Gov. Mikie Sherrill declared a state of emergency starting at 5 p.m. Saturday. A commercial vehicle travel ban will also be in effect on major highways.

“I’m urging New Jerseyans to make plans to avoid travel Saturday evening and all day Sunday,” Sherrill said during a Friday press conference.

The entire state is also under a winter storm warning.

Snow is expected to start falling overnight and continue through Monday, which will likely result in school closures.

“Snow begins after midnight tonight, with the heaviest snow occurring daytime Sunday into Sunday evening (1-2 inches per hour rates likely),” the weather service said. “The storm winds down into Monday morning, with very cold conditions through the week.”

Northern New Jersey counties, which should see all or mostly snow during the storm, remain on track for the highest snowfall totals of 12 to 16 inches, with locally higher amounts closer to 18 inches possible.

“Snowfall rates near 1-2 inches per hour expected during the daytime period Sunday,” the weather service said.

The major ice threat is concentrated along the New Jersey Turnpike, particularly in southwestern counties near Philadelphia.

“There remains a threat for notable ice accumulations ranging from 0.1 to 0.3 inches across the I-95 corridor, southern New Jersey,” the national weather service said. “The combination of heavy snow followed by sleet/freezing rain and breezy northeast winds gusting 20-30 mph could result in some isolated instances of downed trees and power lines, and power outages.”

These ice accumulations will occur after 4 to 8 inches or 8 to 12 inches of snow has already fallen, the weather service said.

County-by-county storm warnings

• Burlington, Camden, Cumberland, Gloucester, Hunterdon, Mercer, Middlesex, Monmouth, Morris, Ocean, Salem and Somerset – From 7 p.m. Saturday to 1 p.m. Monday. Heavy snow with mixed precipitation expected. Total snow and sleet accumulations between 7 and 13 inches and ice accumulations up to three-tenths of an inch. Ice accumulation on power lines and tree limbs may cause tree damage and power outages.
• Bergen, Essex, Hudson, Union and eastern Passaic – From 3 a.m. Sunday to 6 p.m. Monday. Heavy snow expected. The snow may mix with or change to sleet Sunday evening. Total snow and sleet accumulations between 10 and 14 inches. A brief changeover to light freezing rain along with a light glaze of ice may occur Sunday night.
• Western Passaic – From 3 a.m. Sunday to 6 p.m. Monday. Heavy snow expected. Total snow accumulations between 12 and 16 inches. Sleet may briefly mix in with the snow Sunday night.
• Atlantic and Cape May – From 7 p.m. Saturday to 7 a.m. Monday. Heavy snow with mixed precipitation expected. Total snow and sleet accumulations between 4 and 8 inches and ice accumulations up to one-tenth of an inch. Winds gusting as high as 35 mph.
• Sussex and Warren – From 1 a.m. Saturday to 1 p.m. Monday. Heavy snow expected. Total snow and sleet accumulations between 11 and 15 inches.

Forecast for Saturday

Dangerous cold conditions continue through Saturday morning with wind chills below zero for most of New Jersey.

A cold weather advisory is in effect for New Jersey through 10 a.m.

Highs on Saturday will only reaching the upper teens to low 20s ahead of the storm.

Brutally cold week

Arctic air will remain in place through the upcoming week with temperatures below freezing into Friday.

Monday may be the mildest day of the week, with highs in the upper 20s to low 30s, though a strong cold front Monday night will send lows crashing into the single digits.

Wind chills as low as 10 degrees below zero are possible Tuesday morning.

Highs on Tuesday will struggle to reach the teens and low 20s.

The rest of the week is expected to continue with similar temperatures. Lows will remain in the single digits through Friday.

As a result of this prolonged cold, the new snow is not expected to melt much.

Current weather radar