Update, 2 a.m.:

Freezing rain and sleet will fall all night, with ice accumulations on trees and other surfaces reaching close to a half-inch.

Temperatures may get above freezing around sunrise, but freezing rain will likely continue in some of the region into mid-morning.

Sleet and ice accumulations on trees and power lines will likely cause widespread power outages.

If you have a power outage, do not use generators, grills or other gasoline, propane or charcoal-burning devices inside your home or garage. They produce carbon monoxide, a gas that kills more than 500 Americans each year. Generators should be placed outside away from doors, windows and vents that could allow carbon monoxide to seep inside.

Speed limits have been reduced to 45 mph on major highways, including the Pennsylvania Turnpike. Because of ice, the Turnpike has also placed a ban on tractor-trailers.

Update, midnight:

The winter storm warning remains in effect until 4 p.m. Wednesday, with snow accumulations of 1 to 3 inches and ice accumulations of up to a quarter-inch expected.

Snow will overspread the area shortly after midnight, then quickly mix with or change to sleet or freezing rain, which will last at least through Wednesday morning.

The precipitation is expected to become all rain by midday Wednesday.

Expect dangerous travel conditions throughout the snow and ice event. The morning commute will be severely affected.

The speed limit has been lowered to 45 mph on both Route 30 and Interstate 83 throughout the York area.

For the latest weather information, go to weather.gov/ctp or stay tuned to NOAA weather radio.

Report snow and ice accumulation to the National Weather Service in State College by sending an email to ctp.stormreports@noaa.gov, posting to the NWS State College Facebook page or tweeting @nwsstatecollege with the hashtag #CTPWX. &&

Update:

As of 9:45 p.m. there was no snow or ice falling in West Manchester Township.

In anticipation of the winter storm, the York County Office of Emergency Management offers the following preparedness tips:

Residents should maintain an emergency kit in their homes to ensure they have adequate supplies if unable to leave their homes. Such kits should minimally include: A supply of drinking water, non-perishable food, non-electric can opener, first-aid kit, radio, flashlight, personal health needs and extra batteries.

Have the phone number to your electricity provider available. Residents should not call 911 to report power outages unless the outage poses a threat to safety or property. Instead, residents should call their electricity provider.

Residents should have on hand an adequate supply of rock salt or alternate product to melt ice on walkways, as well as snow shovels and other snow/ice removal equipment.

Clear fire hydrants near your home or business from snow so they are readily accessible to fire departments.

Ensure that generators are prepared and ready to safely use pursuant to manufacturer instructions. Never use a generator indoors or near windows or doors. Call an electrician if needed to help with installation, maintenance or preparation.

Take the necessary steps to prepare alternate sources of heat (e.g. kerosene heaters, wood stoves, etc.) if residents plan to use them during a power outage. Follow manufacturer instructions and ensure an adequate supply of fuel.

Make sure your vehicle contains an emergency kit containing, at minimum, water, non-perishable food, a flashlight, extra blankets, maps, jumper cables and a first-aid kit.

Previously reported:

A winter storm warning went into effect for York County at 7 p.m. Tuesday and will continue until 4 p.m. Wednesday, according to the National Weather Service.

There is a chance for snow and sleet to begin Tuesday evening, with the accumulation of 1 to 3 inches and a trace of ice, said Tony Mach, meteorological technician with weather service. Precipitation is expected to be heaviest beginning about midnight.

The area may get freezing rain, snow and sleet after midnight with the rain continuing into Wednesday morning, he said.

The winter storm warning notes that the accumulation of ice could cause power outages.

The Wednesday morning commute will be "severely impacted," according to the warning issued for York and the surrounding counties.

There also is a chance for rain Wednesday afternoon.

The overnight low temperature from Tuesday to Wednesday will be in the mid 20s. For Wednesday, the high temperature will be in the mid 30s with lows around 20 degrees, according to Mach.

—Reach Eyana Adah McMillan at emcmillan@yorkdispatch.com.