NYC: 2004 2nd Consecutive Very Wet Year

[donsutherland1]

In New York City, 2004 marked only the 7th time since regular recordkeeping began in 1869 that the City received 50" or more precipitation in consecutive years. 2003 and 2004 were the first consecutive years with such precipitation since 1989 and 1990.

Only once did the City experience three consecutive years with 50" or more precipitation: 1971, 1972, and 1973.

[donsutherland1]

An issue arose at another message board as to how much wetter New York City has been after 1970 than in the past.

Precipitation has averaged noticeably higher than in the past during the 1971-2004 period. The average precipitation for those 34 years came to 49.92". In addition, wet years (50" or more) were substantially more common than dry ones (below 40"):

• 50" or more: 13/34 (38%) seasons
• 40.0"-49.99": 18/34 (53%) seasons
• Less than 40": 3/34 (9%) seasons

In fact, during the 1971-2004 period there were more 60" or greater seasons than less than 40" seasons: 5 vs. 3.

Prior to the 1971-2004 period, New York City had not seen any 60" or greater seasons and there were fewer 50" or greater seasons in the prior 102 years than during the 1971-2004 period. This may, at least in part, raise some questions concerning measurements. Nevertheless, for what it is worth, for the 102 seasons that preceded the above-noted period, the following occurred:

Average: 42.87"

• 50" or more: 12/102 (12%) seasons
• 40.0"-49.99": 53/102 (52%) seasons
• Less than 40": 37/112 (36%) seasons

Finally, the highest figure for average annual precipitation during a similar length of time to the 1971-2004 period prior to 1971 was 44.74" (1901-1934). That's more than 10% below the present average.

Without doubt, New York City appears to be wetter than in the past. In my view, the issue as to whether changing climate, global indices, urban heat island effect, measurement techniques/technology, other factors, or a combination are responsible is a good one for further study.