In my series on sources of climate data I mentioned the regional climate centers as a great source of information both for specific regions and for national perspectives. The Midwestern Regional Climate Center has a couple of new products that you might be interested in.
One feature that has many national aspects is their new El Niño page. This page provides information on what El Niño is, what the current status is, and what impacts to expect (mainly in the Midwest). There is also an interactive GIS-based national map that shows how this year’s climate relates to that in previous El Niño years. You can visit the page at http://mcc.sws.uiuc.edu/mw_climate/elNino/index.jsp.
Their cli-MATE website also has a new set of interpolated maps which can be used to display past weather across the US. Remember, you have to sign up for a free account on cli-MATE, but once you are in, there is a wealth of information there, including the ability to search for number of days above or below certain thresholds, creating thermographs, and lots of historical data. The map below shows the precipitation for the Southeast since the beginning of the month. Since it is interpolated from station data, it will look a bit different than radar-derived maps, but still shows the overall pattern very well.
You can access all these tools (and get a weather almanac for your smartphone too) at http://mrcc.isws.illinois.edu/.