Winter starts in late December, but Lehigh Valley already saw snow fly on Tuesday

BETHLEHEM, Pa. -- The official start of winter comes Dec. 21. But there's a certain four-letter word in the Lehigh Valley forecast Tuesday.

The National Weather Service has issued a winter weather advisory for Carbon and Monroe counties in effect from 4 p.m. Tuesday until 7 a.m. Wednesday. It calls for total snow accumulations of 1 to 3 inches and ice accumulations of 0.2 of an inch.

• A winter weather advisory is in effect for Carbon and Monroe counties beginning Tuesday afternoon
• Parts of the Lehigh Valley could see some snow accumulation
• This is not 'early season snow,' with the official start of winter more than a month away

In the Lehigh Valley, a rain-snow was leaving a coating of snow in some areas late Tuesday afternoon, mainly in the northern tier.

"Areas farther south and east, you're going to be a little bit too warm," EPAWA meteorologist Bobby Martrich said in his daily video forecast Tuesday morning.

"If you're going to look for areas that could have some sleet and mix to start, it's going to be generally right along I-78," Martrich said.

Rain and snow are expected to continue through the evening, with rain ending Wednesday morning.

What a difference a few days can make

Through the first 13 days of the month, the Lehigh Valley averaged 13 degrees above normal. Highs reached 70 degrees on back-to-back days (Friday and Saturday) — 14 and 17 degrees above average, respectively.

But cold high pressure now is settled north of the region, and meteorologists say it will hang around. It's part of a blast of cold air "swallowing the Lower 48," the Washington Post's Matthew Cappucci said Monday.

In its forecast discussion, the weather service said it's not the only shot we'll have to see snow this week.

"Long story short, this pattern will result in breezy and cold conditions with temperatures about 10 degrees below normal," meteorologist Alex Staarmann wrote, noting Thursday's weather could result in some flurries or snow showers for the southern Poconos and perhaps into northwest New Jersey or the Lehigh Valley.

Staarmann said any accumulations would be a very light dusting, at most.

Snow Squall Awareness Week

The Wolf Administration and the weather service reminded drivers Monday of the threat that snow squalls can pose during the winter months.

The messaging was part of Snow Squall Awareness Week, Nov. 14–18. A snow squall is defined as a period of moderate-to-heavy snowfall of limited duration that is accompanied by strong, gusty winds. Snow accumulation may be significant.

“We all have a role to play in staying safe on roadways this winter,” Pennsylvania Emergency Management Agency Director Randy Padfield said in a news release. “When you get a snow squall warning, the safest thing to do is pause your travel to keep yourself and your loved ones safe, which will help first responders too.”

Earlier this year, a massive pileup caused by a snow squall on I-81 left six people dead and involved 80 vehicles in Schuylkill County.