I recently discovered the website Weatherspark.com , when it was posted on Google+ . This website allows you to obtain very neat graphs of historic weather, average weather, and forecast weather, as well as large maps showing temperatures and radar over large areas. While Wunderground.com , one of my favorite weather sites, had this information, it is much easier to see on WeatherSpark and also loads faster (I still prefer wunderground.com for its forecasts, conditions from user-established weather stations, and smartphone app).
It's also possible to view archived radar images and conditions (temperature, wind, etc), though the method of finding them is not yet intuitive (I basically had to back-program the URLs). Here's a few fun radar videos from past storms. You can scroll around, zoom in and out, or switch between readings such as temperature or wind direction:
Recent severe thunderstorms in southern California (see this blog post). The coastal storms come in about half way through the animation, so if you want you can skip to those.
Radar and wind speed as Irene moves up the US East Coast . You can also zoom into Vermont or other areas for more detail.
August flash flooding in Pittsburgh (wait for the second storm cell!) as described in this blog entry.
June 19, 2009 in Pittsburgh, another day when Junction Hollow had sewage-stormwater overflows.
August 10 thunderstorms that caused large hail and flash flooding in East Middlebury, Vermont. (see here)
July 7, 2011 thunderstorms in Vermont (see this blog post)
May 26, 2011 severe thunderstorms in Vermont (see this blog post)
March 6, 2011 cold front - the radar itself isn't too exciting but watch the temperatures plummet when the cold front passes! (see also this post). This storm started as an unseasonably warm rain that we were worried would cause flooding due to the deep snowpack - but it soon turned into a brief ice storm, and then a record-breaking dump of March snow.
These are just a few memorable weather events, and I'm sure I will think of more later. If you have one you'd like to see, either check out the URL and 'reverse-engineer' it or leave a comment and I'll do it for you. In the future I'll be able to include these maps with descriptions of weather and flood events.