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Extreme Weather: New York's Greatest One-Hour Rainfalls Since 1970

Torrential_rain2

 

I've written posts about New York's biggest rainstorms, its greatest daily rainfall totals and rainiest months.  This post adds to the genre by examining the City's most torrential one-hour rainfalls.  Although an inch of rain falling over the course of a day is a generous amount, a few times each year this amount pours down in just an hour - or less; occasionally the amounts exceed 1.50".

 

Although nor'easters and tropical systems are responsible for the greatest rainfall, these amounts are usually spread out over twelve hours or more.  Thunderstorms, on the other hand, are most likely to produce copious amounts of rain in short periods of time.  August has had the highest propensity for these torrential downpours.

 

60minutes

 

The greatest one-hour rainfall to occur in New York since 1970 was measured during the evening of Aug. 10, 2006 when 2.46" fell between 6:11-7:11 PM.  Five other huge 60-minute deluges have occurred around this date as well: 1.91" fell on Aug. 8, 2007; 1.40" fell on Aug. 9, 1976; 1.92" fell on Aug. 10, 1990, 2.09" fell on Aug. 12, 1989 and 1.76" fell on Aug. 12, 2020.  The most recent one-hour downpour of an inch or more occurred on July 8, 2021 when 1.56" fell between 5-6 PM.

 

Flooding_rain_central_park


(Like all of the previous analyses I've written about heavy precipitation, 1983 is a problem because it's rainfall totals were disavowed due to a malfunctioning rain gauge for most of the year.)

 

HIGH INTENSITY RAINFALL - 1 HOUR   
(1970 - 2013)      
       
Date Amount Time  
Aug 10, 2006 2.46" 6:11-7:11 PM  
July 17, 1995 2.09" 10:19-11:19 PM  
Aug 12, 1989 2.09" 12:45-1:45 PM  
Aug 10, 1990 1.92" 6:17-7:17 PM  
Aug 8, 2007 1.91" 4:36-5:36 AM  
July 29, 1980 1.78" 8:30-9:30 PM  
Sept 8, 2004 1.76" 6-7AM  
June 3, 1991 1.75" 9:06-10:06 PM  
.June 2, 2006 1.73" 2:35-3:35 PM  
Aug 14, 2005 1.73" 5:56-6:56 PM  
Aug 2, 1973 1.65" 8:30-9:30 AM  
Aug 16, 1993 1.58" 5:37-6:37 PM  
Oct 1, 2010 1.55" 4:05-5:05 AM  
July 6, 1975 1.43" 4-5PM  
Aug 9, 1976 1.40" 10-11PM  
June 22, 1973 1.40" 1-2PM  
June 6, 1989 1.35" 1:25-2:25 PM  
May 23, 2013 1.32" 2:25-3:25 PM  
Aug 14, 2011 1.30" 1:02-2:02 AM  
July 6, 2005 1.26" Midnight-1AM  
Oct 21, 1995 1.26" 10:45-11:45 AM  
Note: Excludes 1983      
   

 

 

Beginning in 1982, the most drenching rains by 5-minute, 10-minute, 15-minute, half hour, and 45-minute intervals was reported in the monthly Local Climatological Data report.  The greatest amount of rain to fall in five minute's time was 0.63" on Oct. 14, 2011 between 12:36 and 12:41 AM.  (That's an hourly rate of 7.56".)  And there have been three instances where more than an inch of rain fell in just 15 minutes.  Frustratingly, this information is reported on an inconsistent basis (i.e., since 2000 this information is unavailable for 39 months). 

 

Boots_puddle

 

HIGH INTENSITY RAINFALL - 5 MINUTES  
(1982 - 2013)      
       
Date Amount Time  
Oct 14, 2011 0.63" 12:36-12:41 AM  
June 2, 2006 0.54" 2:46-2:51 PM  
July 26, 2009 0.46" 5:23-5:28 PM  
Aug 3, 2007 0.46" 10:16-10:21 PM  
Sept 10, 1992 0.45" 11:15-11:20 PM  
       
15 MINUTES (1982 - 2013)    
       
Date Amount Time  
June 2, 2006 1.25" 2:39-2:54 PM  
Aug 3, 2007 1.06" 10:06-10:21 PM  
Aug 12, 1989 1.02" 12:56-1:11 PM  
Aug 19, 2011 0.94" 6:26-6:41 PM  
Sept 10, 1992 0.92" 11:06-11:21 PM  
       
30 MINUTES (1982 - 2013)    
       
Date Amount Time  
Aug 12, 1989 1.64" 12:53-1:23 PM  
June 2, 2006 1.51" 2:35-3:05 PM  
June 3, 1991 1.47" 9:22-9:52 PM  
Aug 10, 2006 1.33" 6:12-6:42 PM  
Aug 10, 1990 1.22" 6:46-7:16 PM  
       

 

 

 

 

 

 

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