New Jersey Weather: Higher Snow Amounts in Latest Forecast. Winter storm warnings are expanded to 10 counties.

UPDATE: Early snowfall totals reach 6 inches as the winter storm rolls on and “thunderstorms” are reported

ALSO: When does the snow stop today? Latest forecast on the timing of the winter storm.

Forecasts for the winter storm expected to bring up to 8 inches of snow across New Jersey on Sunday have increased in the latest update from the National Weather Service.

“The weather forecast is for colder and snowier weather,” the weather service said early Sunday, just hours before the storm was expected.

Gov. Phil Murphy has declared a state of emergency for all 21 counties starting at 8 a.m. Sunday.

“Stay off the roads today and stay warm,” Murphy said on News 12 New Jersey, noting that the state is preparing not only for a storm but also for “brutally cold” temperatures throughout the week.

“You never know, but I’m happy with our level of preparation,” Murphy said.

Winter storm warnings have been expanded to include all or parts of 10 counties – Bergen, Essex, Hunterdon, Mercer, Morris, Passaic, Somerset, Sussex, Union and Warren.

The biggest change in the latest snow forecast map is along the Interstate 95 corridor. The area is now expected to receive 6 to 8 inches of snow, as well as nearly half of the state.

According to the weather service, Sussex County could see pockets of snow as high as 10 inches in its higher elevations.

“Snow will move from late morning to early afternoon (southwest to northeast), with the heaviest snow expected between 4 and 9 p.m. During this time, snowfall rates may exceed 1 inch per hour,” the weather service said in its final briefing before the storm.

The weather service has focused on the uncertain forecast for central New Jersey in the days leading up to the storm. A slight shift in track overnight has increased snowfall forecasts in these areas.

“Overall confidence is moderate (50-60%),” the weather service said. “There is still some uncertainty regarding the system’s precipitation and snowfall amounts, as well as how much mixing will occur.”

Winter weather warnings also expanded overnight to cover parts of 11 counties as snowfall forecasts increased in southern New Jersey.

With the exception of the Jersey Shore, most of South Jersey could see 1 to 3 inches of snow, with as much as 3 to 4 inches near the Delaware River.

Four to six inches of snow is expected in the Philadelphia area, which will likely impact the NFL playoff matchup between the Eagles and Los Angeles Rams, which begins at 3 p.m.

AccuWeather’s snow forecast calls for 3 to 6 inches of snow across the northern half of New Jersey, with the exception of the northwest corner in the 6 to 12 inch zone.

After the storm subsides Sunday evening, temperatures will drop and remain dangerously cold into the start of the week.

Expect “temperatures to fall well below freezing Sunday evening and remain below freezing at least through Friday,” the weather service said.

Winter Storm Warnings

Hunterdon, Morris, Sussex and Warren counties from 1 p.m. Sunday to 1 a.m. Monday — Heavy snow expected. Total snow accumulations of 5 and 8 inches. Wind gusts up to 35 miles per hour. Roads, particularly bridges and overpasses, are likely to become slippery and dangerous. Traveling could be very difficult. Snowdrifts could significantly reduce visibility. Snowfall of up to an inch per hour was expected to occur at times this afternoon.

Mercer and Somerset Counties from 1:00 p.m. Sunday to 1:00 a.m. Monday — Heavy snow expected. Total snow accumulations of 4 and 7 inches. Traveling could be very difficult. Snowdrifts could significantly reduce visibility. Snowfall of up to an inch per hour was expected to occur at times this afternoon.

Bergen, Passaic and western portions of Essex and Union counties from 1 p.m. Sunday to 4 a.m. Monday — Heavy snow expected. Total snow accumulations of 5 and 7 inches. Roads, particularly bridges and overpasses, are likely to become slippery and dangerous. Traveling could be very difficult.

Advice on winter weather

Camden, Gloucester, Salem and northwest Burlington counties from 10 a.m. Sunday to 1 a.m. Monday — Some mixed precipitation and snow is expected. Total snow accumulations of 3 and 5 inches. Roads, particularly bridges and overpasses, are likely to become slippery and dangerous. Snowdrifts could significantly reduce visibility. Precipitation should begin as a mix of light snow and rain with possibly some sleet before quickly transitioning to snow. Snowfall of up to an inch per hour was expected to occur at times this afternoon.

Hudson, Eastern Essex and Eastern Union counties from 1 p.m. Sunday to 4 a.m. Monday — Snow expected. Total snow accumulations of 3 and 5 inches. Locally higher amounts up to 6 inches possible.

Middlesex County from 1:00 p.m. Sunday to 1:00 a.m. Monday — Snow expected. Total snow accumulations of 4 and 6 inches. Plan for slippery road conditions. Snowdrifts could significantly reduce visibility. Snowfall of up to an inch per hour was expected to occur at times this afternoon.

Monmouth, Ocean and southeastern Burlington counties from 10 a.m. Sunday to 1 a.m. Monday — Some mixed precipitation and snow is expected. Total snow accumulations of 2 and 4 inches. Plan for slippery road conditions. Precipitation should begin as light rain or a mix of light rain, snow and sleet before transitioning to pure snow. Snowfall of up to 2.5 cm per hour should occur at times as the afternoon progresses.

Dangerous cold

Snow from Sunday’s storm is unlikely to melt quickly as temperatures will fall quickly and remain dangerously cold throughout the week.

Subzero wind chills are expected in parts of the state through Wednesday.

The coldest day could be Tuesday, with highs in the teens and overnight lows in the single digits.

“The coldest period will be Monday night through Thursday morning,” the weather service said. “There is an increased risk of hypothermia and frostbite. Impacts on infrastructure could include frozen pipes and increased demand for heating energy.”