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June 2018

No Thunderstorms in Central Park for the Past 15 Years? So Says the National Weather Service

No thunderstorms symbol


I've lived in Manhattan since 1981, so I can attest to the fact that we get our fair share of thunderstorms; through 1995 the average number each year was nineteen.  However, while doing research on thunderstorms, I was very surprised to discover that since 1996 only three were reported in Central Park (and none since 2003).  This is according to NOAA's annual Local Climatological report for CPK (which is the official reporting site for New York City).  Yet, during these same years the reporting stations at LaGuardia, Kennedy and Newark airports each averaged 25 per year.  I thought, perhaps, this was just an egregious oversight, so I contacted NOAA and I was told that it wasn't an error but, rather, the result of "automation and a lack of human augmentation since the mid 1990s."


I was taken aback by this explanation.  So, the most populous city in the nation no longer reports the incidence of thunderstorms because a human can't be found to do it?   What added to my consternation was that the "Reference Notices" section found in the monthly and annual reports makes no mention that thunderstorms are no longer reported, nor is there an asterisk in the report's month-by-month line for thunderstorms explaining why the number is '0' every month.  Confounding me further is the fact that an annual average is still reported - a number that grows smaller each year since all of the years with no thunderstorms reported are factored in.  So, the most current average listed, 11.1, is completely bogus




Of course, in the grand scheme of things a statistic indicating how often thunderstorms occur is not a crucial one (and it should be noted that any rainfall from a thunderstorm is reported).  However, what troubles me is that there is no explanation that thunderstorms are no longer reported.  Someone not familiar with the New York's climate may think the City actually gets no thunderstorms (and not be aware measurement sites at the three airports collect such information).  And as for the "lack of human augmentation" - isn't that what interns are for?  


Chart - Thunderstorms in NYC


Thunderstorm by month in 2017
Although thunderstorms are no longer reported in Central Park, the way it is displayed on NOAA's annual summary leaves the impression that they are, but there just weren't any storms in 2017.


Curiously, the end of tracking thunderstorms in Central Park coincides with the reporting of days of Heavy Fog for the first time.  In other words, before 1996 the average number of days each year with heavy fog reported (1/4 mile or less) was zero, but since 1996 there have been, on average, 14 such days.  It seems an odd coincidence that the jump in the number of foggy days somewhat coincides with the number of thunderstorms before 1996 while the number of thunderstorms in the present day is what the number of foggy days used to be before 1996.      

Comparing High Temperatures on Mother's Day and Father's Day

Fathers day and mothers day


Since Father's Day is about five weeks later than Mother's Day its high temperature is, on average, about thirteen degrees warmer (82° vs. 69°).  However, in 2018 there was a huge disparity in the temperatures as Father's Day had a sizzling high of 91° while Mother's Day's was only 54°.  This 37-degree difference tied 2010 for the greatest difference in temperature between the two holidays (and there was a 36-degree difference in 1994).  However, not every Father's Day has been warmer.  Since 1960 there have been eight Mother's Days with warmer highs (most recently in 2014), with the greatest difference being 28 degrees in 1970.  And sometimes the two holidays have similar readings; for example, in 2000 and 1974 they had the same high temperature.


Mothers Day Fathers Day



May 2018 Weather Recap - Big Rebound From April

Month of may


After suffering through the chilliest April in more than 40 years, May reversed course and ranked among the ten warmest, ranking sixth (4.5 degrees above average).  The month's unseasonable warmth began right out of the gate as May 1 saw a high of 80° followed by back-to-back days with highs in the 90s.  This was one of the warmest beginnings to May on record (see chart below).  There were also three days later in the month with highs of 88° (5/17), 89° (5/26) and 89° (5/29).  The last time May had five days with highs of 88° or hotter was in 1991 (which was the warmest May on record). 


After the three previous months each had more than five inches of precipitation, May was drier than average, with 3.55" of rain measured.  However, there was a period in which seven days out of eight had rain (May 12-19); this included a severe thunderstorm on 5/15 that moved through during the evening rush hour (five people in the metropolitan area were killed by falling tree limbs).


Twelve days had highs of 80° or warmer, eight days were 10 degrees or more above average, and three days had lows in the 70s.  And although May 2 and 3 had highs in the 90s, the most uncomfortable day was May 26, which had a heat index of 93° (the day's high was 89°).  By contrast, May 2 and 3 had very low humidity and their "feels like" temperatures were lower than the air temperature.  Only six other Mays have had three or more lows in the 70s (since 1930), with two of them being in 2016 and 2015.


Balancing the two days in the 90s were two days with highs in the 50s - May 13 (Mother's Day) had a high of 54° and May 19 had a high of 56°.


Last May was just 3.9 degrees warmer than April, the second closet the two months have been  (closest was 3.5 degrees in 1945).  By contrast, this May was 17.4 degrees warmer than April, the seventh furthest from April (furthest was 18.1 degrees in 1944).  May is typically 9.3 degrees warmer than April.


Chart - warmest starts to May 


Here are links to recaps of previous Mays: May 2017, 2016 and 2015.