Have you ever been in a highway rest area, truck stop or gas station and heard the NOAA weather report broadcasting repeatedly? THAT'S IT!! In most areas it's a simulated (computer) voice that repeats the current conditions and weather forecast over and over, 24/7. When applicable, they will include hazardous weather info. If severe enough, you will here a tone, just like the alert tone on TV for the emergency broadcast system.
It takes usually about 5 minutes to get through the current conditions in the area and another couple of minutes for the forecast. Usually! But it really is that simple. If you want to know the forecast, you turn on a NOAA radio, tune in to one of 7 frequencies (2 others are in Canada for those close to the border), and you get the government's version of what the weather is supposed to do.
ADDED: You've heard of these phone numbers you can call for the weather? Same thing here, only over radio.
Again, I have not tested these newer weather radios such as this:
https://www.amazon.com/Crosse-810-805-Weather-Alert-Flashlight/dp/B0080JIVC2/?tag=treasurenet01-20
I "have" tested various GMRS walkie talkie's that have the NOAA weather bands, but from my experience, they do not pull in a signal as well as a handheld scanner. The scanner I listed in my first post is rather inexpensive, for a scanner, but will give you the weather, plus potentially a whole lot more. The weakness there is its antennae. It's flexible, but not unbreakable. You could try one of the smaller weather-only radios (like above) and see how well it picks up a signal in your area.
Where we live is flat land, but also lots (and lots and lots and LOTS!!) of water! So there are occasionally flooding and flash flooding reports that come over the scanner on the weather bands. I would imagine if there is a chance for flash flooding in mountainous regions, the same would hold true. For nighttime, this is where the SAME technology would shine, as you could leave the radio on in alert mode (on, but silent) and it would alert you ONLY if there is severe weather coming to your specific county.