Thursday, April 17, 2014
Well, you knew it was going to be cold this morning. Portland is in the upper teens for its coldest morning since late last winter. The good news is that the cold isn't going to last more than another 24 hours with milder air poised to move northward late this week and into the weekend. Below are some other readings as of 6AM this morning.
The dry air over us today is creating the need to put some humidity back into the air. When temperatures get this cold and you heat the air inside your house, you lower the amount of moisture. If you are like me, and have forced hot air, the house becomes particularly dry on these cold mornings.
Since the cold won't last but another day, I'm not going to start my humidifier just yet, but it might be a good idea to check on them, clean them and bring it up from the basement.
High pressure moved down from Canada yesterday and brought this shot of what meteorologists call arctic air. The reason we use that term is quite simply the air is of arctic origin and has properties of being cold and dry.
Remember how cool it was the first couple of week of August this year? We actually had some modified arctic air move into the area. It was quite unusual for mid-summer to have an arctic air mass make it so far south. In the summer, the arctic region is getting full, though be it weak sunshine. Therefore, even up there the temperatures are in the 30s and 40s. When the air moves south it warms up. We don't have below freezing air in summer because the sunshine here is so strong that time of year. Temperatures the first two weeks of August in many places were actually cooler than the second two, rather usual, but all due to the arctic air.
Now, in mid-November, the arctic region has been dark for several weeks and temperatures have fallen dramatically. There is a town in northern Canada past the arctic circle called Resolute. In the summer they can reach the 40s, this time of year, it becomes less common to have days much over 10F! The image below shows the forecast for the next several days in that region. Notice the lows at night are well below zero. There is also no sunrise or sunset because the sun stays below the horizon until sometime in February. It might get a bit lighter in the middle of the day this time of year, but in a few weeks it will be very dark, even at noon.
I would like to visit resolute someday, but only in the summer when the sun never sets and the air is a milder 40 above zero, not 80 degrees colder.
Our arctic air will retreat back into Canada tomorrow and leave us with a dry forecast through the weekend. We will see highs back into the 40s tomorrow and lower 50s for the weekend. If you thought winter had settled in, think again, we still have some time to complete our fall chores and get ready for a more permanent cold that surely lies ahead.
Gardening this week
This week my video is on raised beds and how they can help extend the season. I show you several ways you can use raised bed or cold frames to allow your gardening to start earlier and end later each year.
I'll be updating the forecast for the week on Twitter at @growingwisdom Please follow me there. Feel free to comment or ask questions too.Tweet
David Epstein has been a meteorologist for more than 25 years. He spent 16 years in Boston and currently freelances at WGME13 in Portland.
In 2006, David founded GrowingWisdom.com, a business producing educational and marketing videos for the green industry. He currently is a professor at Framingham State College, teaches Jan Plan at Colby College and owns Bloomscapes Inc., a landscape design business.
David authored "Gardens Of New England" and his work has been published in Grolier's Science Annual for 10 years. He lives in South Natick, Mass., and has a summer home in Harpswell.