LEWISTOWN — You certainly won’t call it a heatwave, but temperatures around the Juniata River Valley are expected to rise into the mid- to high-40s by Wednesday, according to the latest weather forecast by AccuWeather.

Today’s forecast predicts it will be mostly cloudy and very cold, with a high of 23 degrees and a 25 percent chance of precipitation. Tonight will be partly cloudy to cloudy, with a low of 15.

“Some of the coldest air of the season is settling in currently and will stick around across the area through Monday night,” AccuWeather Meteorologist Brandon Buckingham said on Sunday. “During this stretch, temperatures will be 10 to 20 degrees below typical average temperatures for mid-December.”

On Tuesday, AccuWeather believes it will start warming up a bit with variable cloudiness. The high could reach 34, with no chance of precipitation. Tuesday night will be partly cloudy with a low of 22.

“A notable change in the weather pattern will occur not only in central Pennsylvania, but for many locations across the central and eastern United States early- to mid-week, as a storm along the West Coast pumps in milder Pacific air into the central and eastern states,” Buckingham explained.

“By Tuesday in Lewistown, temperatures are expected to climb above freezing, then by Wednesday and Thursday, high temperatures can climb into the 40s,” Buckingham added. “While many may enjoy the warmup, those who are hoping for a white Christmas may see their chances dwindle during this timeframe.”

But, there’s still a week to go and the weather forecasts can certainly change.

On Wednesday, the clouds start to leave and are followed by a brightening sky and some warmer temps. The high could reach 46. At nighttime, conditions should become partly cloudy, with a low of 25.

Thursday cools down a bit with a high of 42 as the clouds return. There’s a slight chance of precipitation, especially at night where rain and drizzle are forecasted. The low is expected to be 34.

“By late week, we are monitoring the potential for a notable storm that will track across the central and eastern United States, and it is likely to bring impactful weather across central Pennsylvania in the form of wind and rain, then a rapid return to colder conditions on the back side of the storm,” Buckingham said.

“While it is still too early to specify the exact timing of impacts late week, there is the potential for a flash freeze in the wake of the departing storm late week that could disrupt holiday travel, shopping and logistical plans,” Buckingham added.

Friday temps drop to 39 as conditions become breezy with partial sunshine. On Friday night, it will remain breezy into the evening hours; otherwise, it will be rather cloudy with a low of 26.