I have often wondered why DCA comes in with low snow totals after a huge snowfall, sometimes up to half less than surrounding areas of Washington DC. Sometimes I laugh when I see the disparity in totals. But when DULLES reported a low of 6 degrees in February in comparison to WASHINGTON REAGAN NATIONAL of 20 degrees for a low, I threw my hands up and gave up. I have always known to be a disparity between "FOGGY BOTTOM" and the outskirts of DC. If interested, here is a two page article on the subject.

http://wdtb.noaa.gov/courses/wintera...C_20100317.pdf