Just a reminder, if you want to see the real-time radar map of rain falling over the Hawaiian islands, and/or want to want to see how much rain has recently fallen, check the links below.
Might want to bookmark it so you can find it next time we’re going through a torrential flood.
National Weather Service radar map of Hawaii (pan and zoom to your area of interest)
To confirm how much rain has recently fallen, go to National Weather Service Rainfall Summary page and check the 3hr totals for the areas nearby.
With these tools, you not only see how much rain was falling that instant but also how much rain has fallen recently.
There were a few comments lost when the website was recently restored. To answer the question posed, I use Weather Underground (wunderground.com) to view the animated rain radar map, and also use wind.com to look at rainfall predictions.