Monday morning brought the first below freezing morning to Boston and it was just about on schedule. Normally, the first frost at Logan Airport occurs the last few days of October or the first week of November. We have gone later, but this time of the year and end the growing season is expected.
I'll be updating the forecast throughout the week on Twitter at @growingwisdom Please follow me there. Feel free to comment or ask questions too.
Clear skies are overhead tonight and with the exceptions being Cape Cod and some spots right along the coast seeing a few clouds Where it is clear, temperatures are already in the 20s, where there are clouds, it's in the upper 30s and lower 40s.
This time of year radiational cooling can cause a wide range of temperatures from the coastal plain to inland valleys. Radiational cooling is a meteorological phenomena that occurs under clear skies and light winds. The term is applied to these conditions because the heat of the day is able to radiate into space very effectively thus allowing the coldest temperatures possible by sunrise. If there are even a few clouds overhead, the process is interrupted because the heat that is escaping hits the clouds and bounces back to earth, keeping it significantly warmer.
A night with a blanket of high clouds versus a night with crystal clear skies can lead to temperatures 20 or more degrees warmer from the clouds acting like a blanket. Tonight, a few clouds and a light wind from off the water should prevent our temperatures from falling to lower levels than Monday morning. Some areas will likely get as cold as last night.
High pressure, or air that is piled up at the ground is responsible for our clear skies at night and brilliant sunshine during the day the first part of the week. As the high moves off the coast, the winds will turn more southerly and temperatures will moderate. By Wednesday I expect highs to be more typical of early November reaching back into the mid-50s.
Thursday is even milder with a brief return of 60 degree or higher temperatures. A front to our west will squeeze warm up northward up the coastline and also bring a period of showers. Showers appear most likely the second half of the day and overnight.
On Friday, the front will sweep offshore and bring a return to clear and colder conditions for the start of the weekend. Winds will increase Friday morning and drag in another chilly air mass from Canada. I don't expect the next blast of cold air to be quite as winter-like as the one we are currently experiencing.
It probably seems silly talking about a drought in November, but that's exactly what we are experiencing in much of Massachusetts this fall. The map below shows a wide area, mostly the eastern part of the state, has flipped into a moderate drought status. While this might not seem important, as the growing season has ended, it can impact the ability for some plants to survive the winter.
If you have planted any trees or shrubs this year, especially since August, be sure to water them about once a week and soak them thoroughly. I still don't see any significant rain on the horizon. It's great for raking leaves, but really bad for the ground water situation. If we don’t have a normal amount of rain or snow this winter, we are setting up for major problems next spring.
The clear skies much of this week will give you and opportunity to check out Venus in the southwestern sky. On Tuesday, the setting crescent moon will be close to Venus for a nice celestial show. The image below shows some of the astronomical features in the eastern sky. The image is from earthsky.org.
Unfortunately, we had many clouds on Sunday morning that prevented us from seeing the sunrise eclipse. There are some great photos on the internet of the event and I encourage you to check them out. Here is one I found that someone took on a plane. Very cool.
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.
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