What air mass usually affects Washington and Oregon?
They can bring copious rains and snows to Washington and Oregon. During the winter months, the very cold air masses moving south are called “Continental Arctic” air masses. The source regions of these air masses that affect the U.S. are the Arctic Basin and interior North American north of 55 degrees latitude.
How does air mass affect weather?
When winds move air masses, they carry their weather conditions (heat or cold, dry or moist) from the source region to a new region. When the air mass reaches a new region, it might clash with another air mass that has a different temperature and humidity. This can create a severe storm.
What 4 air masses affect weather in the United States?
Five air masses affect the United States during the course of a typical year: continental polar, continental arctic, continental tropical, maritime polar, and maritime tropical.
What type of air mass affects North America?
The 4 types of air masses that impact North America most commonly are maritime tropical (mT), continental tropical (cT), maritime polar (mP), and continental polar (cP).
Which air masses bring dry weather to the United States?
2. A continental polar air mass can form over the land during the winter months. In the Northern Hemisphere, it originates in northern Canada or Alaska. As it moves southward, it brings dry weather conditions to the United States.
What kind of air masses affect the weather?
They form from the modification of another air mass, usually continental polar or maritime tropical, which moves over the cold ocean areas. This is the predominate air mass west of the Rocky Mountains and in western Europe. The Maritime Polar air mass over the North Pacific effects the weather in the upper northwest causing the rainy season.
What kind of air mass is in Seattle?
When Rossby waves dip south from the Arctic Circle they bring with them wisps of continental arctic and polar air into the northern reaches of Washington. The continental polar air mass is usually responsible for any extreme temperatures in Seattle.
What kind of air masses drop out of Canada?
The Continental Polar (cP) and the Maritime Tropical (mT). The Continental air mass will begin to drop south out of Canada and bring cold air to the south with a dominant high pressure system. Semi-permanent high pressure systems determine migration of the air masses during the summer and winter months.
What kind of air masses cover the United States?
Maritime Tropical (mT) Air Mass Maritime Tropical airmass will be very warm and humid. A “tropical continental” airmass usually covers much of the United States in the summertime. Other airmass types include “arctic”, “equatorial”, and “monsoon”.