13. A warm air mass that is cut off from the ground is said to be
14. A swirling center of low air pressure is called a(n)
15.
are high-pressure centers of dry air.

Explanation:

Been a while since studying weather... so double check these...

13. Warm air mass above ground => an 'inversion' ... Normally, atmospheric temperature decreases ~2°C / 1000 ft... Reversal of that trend is due to trapped warm air above ground and is referred to as 'an inversion'.

14. Swirling center of low air pressure => a 'cyclone' ... In the Northern Hemisphere the flow is counter clockwise but in the Southern Hemisphere such a phenomenon is clockwise flow.

15. High-pressure centers of dry air => a 'ridge' which is contrast to a low-pressure center called a 'trough'.  Hope these are right. :-)

the product of the pressure and volume is also constant