❗ Cold air is denser and thicker than warm air, so it usually sinks as warm air increases. Cold air sinks which causes a transient accumulation of water near the earth's area and thus an area with a high pressure in regions where winds meet at high altitude. With an increase in altitude air pressure reduces, so high pressure is in fact a relative concept. Weather forecasters commonly use this to signify high pressure relative to normal atmospheric pressures at that level.
