Last year, for the first time ever recorded, Portland had to wait until November to record a temperature reading of 32 degrees or lower. This year we reached that unwelcome (for many) milestone on the 18th of October.

If you escaped without a freeze this morning, you likely won’t Monday. The air is very dry and will remain chilly all day both today and tomorrow. Temperatures this afternoon will rival the coldest high temperatures on record for the date. While the frost isn’t terribly unusual, the fact we won’t get out of the mid-40s today is more noteworthy.

There was snow in the mountains and northern Maine yesterday as the cold air arrived. This isn’t the earliest snow has occurred, but it does remind us summer is definitely over and winter sports will be taking place real soon. Sunday River is forecast to open Monday the 19th of October.

High pressure has come down from Canada in much the same fashion as last winter. This high has brought unusually chilly air to the region and put an end to the growing season in most areas. Tomorrow should be a few degrees colder with 20s widespread.

The map of temperatures below shows how the coldest air is presently across the northeast corner of the nation. I drew a line representing the jet stream on the map to help see how the air is flowing at the upper levels above the cold.

The core of the cold air pushes out to sea Monday afternoon and milder air ensures no frost the rest of the week. If you moved plants inside, you could put them back out Monday afternoon for the rest of the week. The best way to acclimate houseplants to being moved back inside is to move them in at night and out during the day, but unless you have just a few plants, this becomes impractical.

Milder air means several days back into the 60s from Tuesday through Thursday before another cold front knocks readings back again. The shot of colder air this weekend won’t be quite as chilly as this one.

Dry October
There hasn’t been consistent moisture this month and after a mostly dry September, the drought conditions are still firmly in place. You might not think about a drought this time of year or even the need to water, but this is the case. October can be one of the driest months of the entire year so it’s not surprising we are dry.

Wetter November
Typically the jet stream reconfigures itself during November and brings wetter conditions. As the colder air from the north starts interacting with milder air to the south more rain should start appearing the forecast.

Look East Monday
There’s a great celestial show happening early this week. Venus is the brightest object in the eastern sky during the pre-dawn hours. You can also see Mars and Jupiter close together under Venus. If you have a clear view of the horizon and its dark mercury is also visible low in the sky.
The picture below courtesy of Skynews.ca provides a great idea of what you will see. Venus is so bright it will be visible until sunrise and if you look hard, you can even see it post 7 a.m. for a few minutes.