Honestly, our weather has been a hot mess. We were in the high 70s the beginning of the week and 40 the nest day, 54 today, going to be high 60s tomorrow. Thursday we will be in the 40s for the day then drop that night down to 8. Our winters are usually around the high teens/low 20s but this year has been a mess.
If the chickens are in the coop but the wind is not in the coop, the wind chill does not matter.
So you can ignore that part of the weather forecast (unless you want to add wind protection to the run.)
What temperatures have you had in the past few weeks? If the chickens have been gradually adjusting to cooler temperatures, they may do fine, and you will just need to make sure they have thawed water at frequent intervals.
If you want to warm the coop just a little bit in the cold morning, you can fill a big bucket with hot water, put the lid on tight to keep it from spilling or evaporating, and sit it in the coop. I think it helps the person feel better more than it helps the chickens, but it does add a little warmth without any risk of fire. You don't want spilled water or extra humidity in the coop, so do make sure the lid is secure. (Not a long-term solution, unless you really want to build muscles by carrying all those buckets.)
But if they are used to much warmer temperatures, and if this is expected to be a brief cold snap that will not happen again, you might consider bringing them into a garage or similar space for the coldest night or two. I would not bring them in for normal winter temperatures in your climate, but it might be the easiest way to deal with an extreme cold snap that goes way below what is usual for your area. (I don't know your weather well enough to know how common that temperature is.)
