Islip hit by the meteorological hat trick in the last half-year

[bluewave]

 

http://www.nws.noaa.gov/oh/hdsc/aep_storm_analysis/11_Islip_2014.pdf

 

Exceedance Probability Analysis for the Islip, NY Rainfall Event, 13 August 2014

Hydrometeorological Design Studies Center

National Weather Service National Oceanic and Atmospheric Administration 1325 East­West Highway, Silver Spring, MD 20910

E­mail: [email protected] Updated: 22 August 2014

 

The Hydrometeorological Design Studies Center (HDSC) analyzed annual exceedance probabilities (AEPs) for the Islip, NY rainfall event that occurred on 13 August 2014. AEP is probability of exceeding a given amount of rainfall at least once in any given year at a given location. It is an indicator of the rarity of rainfall amounts and is used as the basis of hydrologic design. The Islip event delivered rainfall amounts that exceeded 11 inches in 3 hours in some locations, causing extreme flash flooding.

The rarity of this event is illustrated in two figures below. Figure 1 shows how the maximum observed rainfall amounts compared to corresponding rainfall frequency estimates for AEPs from 1/2 (50%) to 1/1000 (0.1%) for durations from 30 minutes to 72 hours for a rain gauge in the Islip area ­ KISP, MacArthur Airport (40.7939°N, 73.1017°W, 98 ft elevation). The KISP gauge is part of the Automated Surface Observing System (ASOS). The AEPs are preliminary estimates from unpublished NOAA Atlas 14, Volume 10, Version 1 and may differ from final estimates, which will be released in 2015. The upper bound of the 90% confidence interval for 1/1000 AEP is also shown in the figure to illustrate uncertainty associated with the calculation of AEPs, which increase as the AEP becomes smaller. As can be seen from Figure 1, probabilities are less than 1/1000 for durations between 45­min and 24­hour. Both 2­hour and 3­hour amounts exceed the upper bound of the 90% confidence interval of corresponding 1/1000 estimates.

 

 

[tmagan]

Just watching CNN international weather and saw that Montpellier, France (on the south coast) had 10.6" of rain in a four hour period on Monday.

[Bobby]

Although maybe not in a 12 month period but many parts of N and S Carolina and possibly MD have seen all 3. But again quite the statistic for Islip. Although Sandy wasn't a hurricane at Landfall nor was it near Islip.

[tmagan]

Islip, NY has just observed nine inches of snow in two hours, something you see in the great lake effect bands.

[Cobalt]

 

[psv88]

On 5/7/2018 at 12:50 PM, Cobalt said:

 

And 4 in the past 3 years...since i moved to my house in Suffolk in April 2015 we have had 4 blizzards, at least one every year, and 2 in 2018...just ridiculous out here.

[tmagan]

Lets take a reset:

Hurricane Warning for Henri in August, even though it didn't make landfall on Long Island, and not as a hurricane

Tornado outbreak in November

Verified blizzard conditions today