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Thunderstorms produce flash flooding and severe weather (tornadoes and damaging winds) across the Northeast US

By Scott Bachmeier •

1-minute GOES-19 Infrared Window images with plots of Flash Flood Warning polygons (red) and 1-hour precipitation accumulations at METAR sites (white), from 1901 UTC on 20 August to 0200 UTC on 21 August

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared Window images (above) included Flash Flood Warning polygons and 1-hour precipitation accumulations during a period when thunderstorms produced heavy rainfall and flash flooding across parts of the Northeast US on 20 August 2026. Notable rainfall occurred in the New York City area, with over 5 inches recorded in Suffolk County on Long Island; the highest 1-hour precipitation accumulation at nearby La Guardia International Airport was 1.82 inches.

1-minute GOES-19 Visible images with time-matched plots of SPC Storm Reports, from 1838-2318 UTC on 20 August

Some of these thunderstorms also produced tornadoes and damaging winds — 1-minute GOES-19 Visible images (above) and Infrared Window images (below) included time-matched plots of SPC Storm Reports.

1-minute GOES-19 Infrared Window images with time-matched plots of SPC Storm Reports, from 1838-2318 UTC on 20 August

The thunderstorm that produced a tornado in Dover, Delaware exhibited a well-defined Enhanced-V storm top signature (below).

GOES-19 Infrared Window image at 2218 UTC on 20 August with time-matched plots of SPC Storm Reports [click to enlarge]

Categories: GOES-19, Heavy rain / flooding, Severe convection