I've had many people asking me over the past few days what's been going on with the weather lately. No surprise, given that we've had temperatures flirting with 80 degrees in some spots during the middle of the week. Not to mention the fact that two days featured tornado watches across central Virginia, with actual tornadoes being reported outside of the Richmond area. All of these things are a little out of the ordinary for Virginia in late October.
This Friday night, things will turn around dramatically. A sharp cold front has moved through the area and a large area of high pressure is settling in. An area of high pressure is a large dome of sinking area and clouds don't tend to form in this type of environment. The winds will also die down as the high pressure moves in Friday night. The clear skies and calm winds are the two main ingredients for what we call radiational cooling. This simply means that the heat that was acquired during the afternoon will be able to effectively escape back into space during the overnight because there's nothing to keep it from doing so. Clouds generally help to keep our temperatures warmer during the overnight, preventing outgoing radiation (heat energy) from escaping into the upper atmosphere. Gusty winds help keep the atmosphere mixed up, preventing temperatures from dropping off as much. This explains why the clear sky, light wind combination generally leads to some of our coldest nights.
Temperatures are expected to get very close to the freezing mark and maybe even a bit lower in some of the coldest spots by early Saturday morning. If you still have any outdoor plants that are sensitive to these types of weather conditions, you'll want to take all of the necessary precautions on Friday night before the temperatures drop. Freeze watches and warnings have gone up across our entire viewing area and they'll stay in effect until Saturday morning.
In the meantime, there's another UVA home football game on Saturday at noon, so I'm expecting tailgating temperatures to start out in the 30s and gradually warm through the 50s by kickoff. Dress warm and bring the hot chocolate. Hope everybody has a great weekend!