I’ve yet to see any mapping program with this as a feature, but I think it would be really useful.
Put the weather radar as an overlay on the map, then let the user choose how severe of a storm they’re comfortable driving through. If you’re ok driving through a shower, but not through a severe thunderstorm, Waze MIGHT be able to route you around it.
Just a thought.
Its fairly common in the marine mapping products. So it is certainly doable. No sure it will make it to the top of the waze priority list soon.
Instead of an overlay, which might be distracting, maybe just pulling data based on radar and other technology to pinpoint those “dangerous” or “warning” locations and post those on the map automatically?
(I’d like to see a satellite view of the ground before other overlay-type info.)
Big time good idea to have precipitation radar. Come to New Hampshire and drive with a snowstorm bearing down or anywhere when thunderstorms are around. Airplanes have it, it’s high time car drivers have it.
Airplanes have real-time weather returns on their screens because they have a weather radar detection system inside. You would have to get that on your car which I believe is not yet available…
However pilots get a satelite picture as well as general weather charts on the ground during dispatch which allows them to select a more appropriate route if needed. This would be the feature Waze may need to work on in the future which I also believe is not impossible. 
It would also be nice if we can turn on or off certain layers from the client, based on the individual preference.
I had a casual discussion with whomever runs the Waze Twitter account and they made it clear they were not planning on implementing this feature.
It’s a shame, because I also think it would be quite useful.