qForm over low latitude
oceans and as such are very warm,
humid, and unstable.
qmT air masses from
Atlantic and Gulf of Mexico is the
primary source region for the eastern
U.S.
qAs air advects over the
warm continent in summer the
high humidity and high heat
occasionally combine to dangerous
levels.
qmT air masses have an
enormous influence on the
southwestern U.S, particularly in summer.