More snow accumulation tonight says NWS in late-day forecast

BETHLEHEM, Pa. — A cold front passing through the region delivered another round of chilly air as we await our next snow chance Friday night.

It also delivered something else — the proper setup for another snow event in the Lehigh Valley.

The National Weather Service has updated its winter weather advisory in effect from 10 p.m. this evening to 10 a.m. Saturday for 2 to 4 inches, and locally 5 inches of snow.

Snow may briefly become heavy late tonight before tapering off early Saturday.

NWS warns drivers to "plan on slippery road conditions."

The advisory covers parts of east central, northeast and southwest Pennsylvania, along with central, northern and northwest New Jersey.

It comes days after a fast-moving storm swept quickly through the area but packed a punch, bringing nearly a foot of snow to several spots.

Will the storm overperform?

The heaviest snowfall rates are expected to be south of the Lehigh Valley, forecasters said.

But there’s a chance the system could overperform in some areas.

Models early Friday actually were pushing the storm “pretty far to the north,” EPAWA meteorologist Bobby Martrich said in his latest video update.

Martrich suggested that a "final call" snow map slated to be issued at 5 p.m. could bump up snowfall totals in the area because of the jet streak— a part of the overall jet stream in which winds along the core flow are stronger than in other areas along the jet stream.

Martrich said the right front quadrant of the jet streak is where this storm will find its heaviest lift.

“That’s why it makes sense that you’re going to see the highest snowfall rates in those areas and why we think it could be an overperformer.”

The “sweet spot” of the storm is expected to be the Philadelphia metro area and points south, where 3 to 5 inches of snow could fall.

Timing and impacts

Snow is expected to overspread the area late tonight, arriving between 11 p.m. and midnight.

Martrich said areas south of the Lehigh Valley could see snowfall rates of an inch per hour.

“It’ll pile up quickly down there,” he said, not ruling out some "localized" snowfall could reach 6 inches.

The system is expected to pull out quickly Saturday morning, but the weather service said snow showers could continue in northern areas through much of the day.

“However, the real accumulations should be long done by 10 a.m.,” its forecast discussion said.

He said drivers should expect slippery road conditions through the duration of the event.