If the winter of 2015 wasn't tough enough, on March 24 the New York office of the National Weather Service issued a statement announcing that the season's snowfall in Central Park had been revised upward by 3.3". This is the only time I can recall weather records being changed so significantly weeks after the fact. The official announcement can be found here. I would have loved to have been privy to the discussions that led to this decision. I'm especially curious how NWS pinpointed the three snow events that were under-reported (Jan. 6, Jan. 24, and Feb. 2).
For quite a few years weather hobbyists, myself included, questioned the measurements from Central Park since it consistently reported lower accumulations than Newark Airport, LGA and JFK (yet it often had higher rainfall); therefore, it was gratifying to see the issue addressed. Perhaps it had something to do with the fact that the other reporting locations are at airports (perhaps tree branches in the park were blocking snowflakes?). A post from New York Metro Weather addressed the subject and its implications for confidence in future snow totals.
A number of other revisions have resulted from the NWS announcement:
- With 50.3" the new total, the winter of 2015 moves from 22nd to 18th snowiest.
- Feb. 2's snowfall of 5.0" (revised from 3.3") ties it with 1874 as the snowiest Feb. 2. This new amount also increased the winter's number of snowfalls of four inches or more to six, tying it with last winter.
- With Jan. 6's total snow revised from 0.5" to 1.0", the number of snowfalls of an inch or more this winter increased to 13, which is one more than last winter (which had seven inches more total snowfall) and the most since the winter of 1994.
- Winter 2015 is now the fourth of the past six to see 50" or more of snow. By comparison, the average is one such snowy winter every ten years.
Then the following winter there was revision made to that season's snowfall - and this one had more of an implication. On Jan. 23 a blizzard dumped 26.8" of snow, putting it just 0.1" behind the biggest accumulation of all time from ten years earlier. Then three months later the National Weather Service announced that snow from a final band, which amounted to 0.7", had been omitted. This additional accumulation upped the storm's total to 27.5" and made it New York's biggest snowstorm.
These revisions brought to mind 1983 when it was announced at the end of that year that Central Park's rain gauge had been broken since May. This was an especially crucial matter since 1983 reported the most rain on record, but was it valid? This put the NWS in a sticky spot, but rather than address it they let it linger for years. The issue resurfaced in 2011 when that year received the second greatest annual rainfall. However, some thought it could lay claim as rainiest because of 1983's shaky measurement. Pressed, the NWS finally decided that the 1983 record would stand - although previous NOAA climate reports left monthly rainfall totals for 1983 blank and noted the equipment malfunction. I wasn't convinced by their argument.