Answer: These are called WARM FRONT.
Explanation: In meteorology, warm front is known as a trailing edge of a retreating mass of cold air. It involves a warm air mass replacing a cold air mass. They are typically located on the equator-facing edge of an isotherm gradient.
Clouds ahead of the warm front are mostly stratiform, and rainfall gradually increases as the front approaches.
You didn't show a picture of the tree so I don't know either
Pretty sure its called the 38th Parallel, or the Demilitarized Zone. :)
The Earth is roughly a sphere. The Earth is an irregularly shaped ellipsoid.
