Update: York County and the rest of central Pennsylvania should prepare for a freeze Friday night, according to the National Weather Service.

The NWS has issued a freeze warning for 2-9 a.m. Saturday for York and the surrounding area. The freeze is expected to end the traditional growing season for the region, the service said.

A cold front will push temperatures below 30 degrees in the early morning hours, the NWS said.

Gardeners and farmers should harvest or protect sensitive plants, and indoor plants should be brought inside or covered, the service said.

Previous story: If you haven't had to do so already, prepare to turn on the heat Friday night as cold temperatures move into York County.

While you're at it, you may want to cover outdoor plants to protect them against the frost expected to hit the area as nighttime temperatures drop below the freezing point.

The National Weather Service has issued a freeze watch for York, Adams, Cumberland, Dauphin, Franklin, Lancaster and Lebanon counties that runs from Friday night to 9 a.m. Saturday.

The first frost of the fall and winter seasons is a little early this year.

Typically the first freeze of the year occurs in mid- to late October, said AccuWeather senior meteorologist Michael Pigott.

“So this is a bit early,” he said.

Frost: The early frost is the result of the second cold front that will move into the area in as many days.

The front with cold, high pressure will move into the area Friday and cause the thermometer to dip to 29.

“The second cold front will bring even colder temperatures to the area,” Pigott said.

But come Saturday, temperatures will rebound to a high of 58 with lots of sunshine and a nighttime low of 45, according to AccuWeather.

Sunday will be even warmer, with a high of 70 and partly cloudy skies.

The nighttime low Sunday is expected to be 56, according to AccuWeather.

Despite the earlier-than-normal frost, temperatures throughout the winter aren't expected to be colder than in years past.

While the eastern part of the state will likely see a higher-than-average amount of snowfall, Pigott said temperatures in York County are expected to remain at normal levels.

Colors: Even with the frost, state forestry officials say fall colors in the southern part of the state will stick around through the end of the month.

According to the Department of Conservation and Natural Resources' Bureau of Forestry's fall foliage report, trees in Michaux State Forest, part of which is in northwestern York County, are expected to be in full color by Monday.

White oaks are bringing maroons and deep purples to the landscape, the report says.

Oaks and tulip trees are going from “summertime green to rusty brown and golden yellow,” the report states.

— Reach Greg Gross at ggross@yorkdispatch.com.



Protecting outdoor plants

Worried about a frost predicted for Friday affecting outdoor plants?

Here are few tips to protect them from the deep freeze:

* Water the soil thoroughly. Wet soil holds heat better than dry soil, protecting roots and warming air near the soil.

* Sheets, drop cloths, blankets and plastic sheets are suitable covers for vulnerable plants. Use stakes to keep material from touching foliage. Remove the coverings when temperatures rise the next day.

* For a short cold period, low plantings can be covered with mulch, such as straw or leaf mold. Remove once the danger of frost has passed.

* For a small tree, place a 100-watt lamp designed for outdoor use on the branches near the trunk. It can emit enough warmth to reduce frost damage. Holiday lights (not LED lights) serve a similar function, but be sure they don't touch any covering materials.

* Spray an anti-transpirant on the foliage of cold-sensitive plants to seal in moisture. One application can protect for up to three months.

* Cluster container plants close together and, if possible, in a sheltered spot close to the house.

Source: University of California Marin Master Gardeners.