Searching by miles at this time of year is the wrong approach, IMO. I've seen fares cheaper to Philly from SFO than to PHX. Here's the blurb I copy/paste for how to use google.com/flights for people who want short segment runs. You can use it without a destination entered and get similar results for your needs as well:

"The easiest way to search for a close-in segment run is to use google.com/flights to narrow your choices down. Enter your departure city, then leave the destination blank. Tighten up the dates on the calendar for a same day trip out and back, then click on the 'Places' icon which will cause a map to appear. Zoom in and move the map around until you get good results nearby, then simply advance through the dates. You may also constrain your results to one particular airline or alliance, such as United only or all Star Alliance flights (which will capture UA+US).

Another idea is to use the calendar function on ITA. Use your home airport as both your origin and destination, with a length of stay of zero nights. Then click on the "nearby" link at the end of the destination line to expand your search by 200 miles or so. That'll capture out and back flights in a tight radius which does the heavy lifting for you."