How do you know if there is dry air coming in behind a storm system?

Question

How do you know if there is dry air coming in behind a storm system?

Answer 1

Look at a water vapor loop. Darker colored areas depict the drier air, and whiter colored areas depict the moister air. You could also look at a dew-point map and try to estimate how the upstream dew-points will translate into your region behind a frontal boundary.

Water Vapor Loop: http://weather.unisys.com/satellite/sat_...

Dew-point map: http://weather.unisys.com/surface/sfc_co...