1.   An unseasonably warm air mass was further warmed by compression, resulting in the unprecedented May heat.

2.   A very warm air mass arriving from the Midwest was further warmed by compression as breezes descended the Appalachians.

3.   Air at high pressure sinks, and compression warms it.

4.   Mild southwesterly winds can be further warmed by compression as they descend from the Rockies.

5.   This week, the area will be dominated by dry winds from the west which are warmed by compression as they descend from the Rockies.