(NEWS10) – On this week’s Weather 101 we will discuss air masses, where they come from, what they are and how they affect our weather here in the northeast.
A few things about air masses, there are two main divisions of air masses and they are categorized by their moisture content.
Continental air masses, designated with the lowercase “c” originate over continental landmasses, therefore, there is no moisture and they are considered to be very dry air masses.
Maritime air masses, designated with the lowercase “m” originate over the oceans and thus have a fairly high moisture content.
Each of these two divisions of air masses are then divided based on the temperature of the surface where they originate.
Arctic air masses, designated with the letter “A” are very cold, these types of air masses originate over the arctic and Antarctic regions, think the North and South pole.
Polar air masses, designated with the letter “P” aren’t AS cold as their arctic counterpart, as they typically originate from higher latitudes in the northern and southern hemispheres both over land and over water.
Tropical air masses, designated with the letter “T” are warm and hot, as they originate over lower latitudes, think tropics or desert, both over land or over sea.
So when we put these two divisions together we get:
Continental arctic (cA): This particular air mass is sourced over the poles and thus are very cold and dry, We will occasionally get this air mass in the winter months with a strong storm system and a big arctic high behind that. This would bring Arctic air with sunny skies for the northeast. This can sometimes lead to record-breaking cold in the Midwest and Northeast.
Continental polar (cP): This originates in the higher latitudes both in the north and south hemispheres, with it being continental this would have characteristics similar to the Arctic air mass but it wouldn’t be AS cold.
Maritime polar (mP): Sometimes the Continental polar air masses can move over the oceans, mainly in the northeast and the northwest. This would pick up more characteristics of a maritime air mass as it picks up moisture from the oceans. This would typically be associated with colder temperatures, cloudy conditions and sometimes wintry precipitation.
Continental tropical (cT): Typically continental tropical air masses form over the desert southwest in the United States and this is what you would associate with very hot and dry air. Typically in the summer months, this could lead to record-breaking heat in the southwest and occasionally this air mass can move into the northeast depending on how strong it is which would bring a hot and dry air mass to the northeast.
Maritime tropical (mT): Sometimes, just like the polar air masses, tropical air masses can move over the oceans. This would pick up maritime characteristics which would greatly increase the moisture within the air mass itself. This is typically what we see in the summertime months as it moves up the east coast and into the northeast. This is the type of air mass you think of in those hot steamy months in the middle of summer with warm temperatures and high humidity levels.
Sometimes these air masses battle each other. What I mean is a blast of polar air (continental polar) will dive south out of Canada and meet up with a maritime tropical air mass. Where they meet storm systems will develop along that boundary. In the winter months, this is when we can get our big winter storms in the middle of the country, or even along the east coast. Think big winter storms or even blizzards.
In the summer months, the polar air mass will still sometimes move south and meet with the warm humid air from the maritime tropical air mass. Where these meet, especially in the warmer months it is a good chance we can get a cold front to develop. Along this boundary is where we can get severe weather to develop.
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