I am a waterman and when one is, he "Keeps a weather eye aloft" or he becomes another name on a memorial plaque.
The problem with most of the phone level weather apps is that they tend to be local. So, if you don't know a city or at least a zip code, they can be a problem. We carry wire, so every morning I do a lot with numerous sites. (Too many to list here and some would make no sense to someone not experienced to read them.) To understand the expected weather for the day, be it a road day or local. The main data site for me is
Unisys Weather. If you do not understand what it tells you, there are parts that are more citizen oriented that you can use.
There is an app for android called "Raindar". It locks into the GPS (if you have) and give a precipitation picture all around and can be requested to show current movement. I find this to be helpful if the weather is likely to be an issue during a road day.
Matt