Points to Remember. 1  Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa. 2  The plant contains the mind-altering chemical delta-9-tetrahydrocannabinol (THC) and other related compounds. 3  People use marijuana by smoking, eating, drinking, and inhaling it.
A cold front is symbolized on a weather map as a line with triangles. The triangles can be thought of as icicles. Cold fronts are often coloured blue. The presence of a cold front means that cold air is advancing and pushing underneath warmer air.
This vertical cross-section of a cold front shows cold air behind the cold front (dark blue lines) advancing into warmer air ahead of the front. Where the two air masses meet, convergence often occurs which can result in upward motion of air parcels. If the air contains enough moisture, rain can occur. If the air also is unstable, thunderstorms can develop as well. This is a simplified view of a cold front. Sometimes, fronts aloft (above the surface) can result in precipitation ahead of cold fronts.