[Gordonjcp]

Doing something like that on VHF is utterly idiotic if you need to cover a large area, unless it's as flat as a snooker table.

Do it on SW, around 6MHz, and you'll cover a 300-mile radius with 50 watts.

[RF_Savage]

But weather is more local. 6MHz might not get that good of a range with low powers like that thanks to the really high amounts of man made noise on HF bands.

So the inherently local nature of VHF complements the inherently local weather alerts. Floods and tornadoes are not an issue at a distance of 300 miles.

[rsaxvc]

That seems rather limited compared to EAS in practice, since some EAS stations will relay appropriate alerts, and since EAS runs over both broadcast FM, AM, and TV stations.