November snowfall is relatively common in Baltimore, but usually leaves just a trace of flakes.Thursday&#8217;s dose of sustained wintry precipitation was the most the region has seen in November since at least 1989, and the earliest the area has seen measurable snowfall in 22 years.The last time measurable snowfall &#8212; defined as a tenth of an inch or more &#8212; fell here earlier than Nov. 15 was in 1996, when 0.3 of an inch fell Nov. 12, according to National Weather Service records.The official snowfall at BWI as of 7 p.m. Thursday was 1.7 inches. That was the most for the airport in November since 3.8 inches fell over two days, Nov. 22-23, 1989.Traces of snow have been recorded at BWI in November more commonly. It has only been five years since snowflakes were observed at BWI by this point in the season.A trace of snow was reported Nov. 12, 2013, and also a year before that, Nov. 13, 2012.A trace also fell Oct. 29, 2011. That storm dumped several inches of wet snow north and west of Baltimore, but BWI snowfall serves as the official mark for comparisons over the years.A &#8220;trace&#8221; is meteorologists&#8217; official term for reporting any visible snowfall that does not accumulate enough to be measured with a ruler.Baltimore&#8217;s earliest trace of snow on record came Oct. 9, in both 1895 and 1903.The record for the region&#8217;s earliest measurable snow dates to Oct. 10, 1979, when 0.3 of an inch fell at BWI.At some point in Baltimore&#8217;s 127-year-old snowfall record book, at least a trace of snow has fallen on each date in November. The region sees at least a trace of November snow in more than two out of every three years.