Probably silly question

[moogyboobles]

Just how is radar can tell which clouds will rain/snow and which are just floating about being clouds?

Is it how they look, or height or something? Just wondering as I have some lovely looking dark clouds over me but radars say no ppn for miles. I am clutching at straws!

[Nick F]

The radar picks out precipitation falling from the clouds rather than what's in the clouds, quite often cloud can look ominous like it will drop something, but sometimes sunlight can make it look darker at its base and give the perception that it might rain or snow from it. Also, preciptn. can evaporate before reaching the ground - due to the air beneath the cloud being very dry, or the cloud may not be super-saturated or heavy enough for anything to fall from it.

[moogyboobles]

Thank you Nick!