q Maritime polar air masses form over upper latitude oceanic regions and are cool and moist.
qmP air masses
form over high-latitude ocean as cP air masses move out from the interior of continents. (i.e., cP à mP).
qOceans add
heat and moisture into the dry and cold cP air masses.
qAlong the
west coast of the U.S., mP air affects regions during winter and may be present before mid-latitude cyclones advect over the continent.
qAlong the
east coast, mP air typically affects regions after cyclone passage as the mP air wraps around the area of low pressure.