Hey there Mark J1,
Thanks for reaching out to the Apple Support Communities.
To get started, do you currently have Precise Location enabled for the Weather app in Settings > Privacy & Security > Location Services? If not, this may need to be turned on first before notifications for the weather app can be enabled.
For more details, check out the information in the following resource that can help with turning on weather notifications for your device: Manage weather notifications on iPhone - Apple Support
Turn on weather notifications for your location
1. Go to Settings > Privacy & Security > Location Services > Weather, then tap Always.
2. Turn on Precise Location to receive the most accurate notifications for your current location.
3. Open Weather, then tap to view your weather list.
4. Tap , then tap Notifications.
If prompted, allow notifications from the Weather app.
5. Below Current Location, turn on notifications for Severe Weather and Next-Hour Precipitation (green is on).
6. Tap Done.
Note: Not available in all countries or regions.
Keep us updated on the results.
Take care!