26-28 May – Severe weather and flash flooding associated with a slow moving front (click on images to enlarge)
A slow moving from tracked into the region from the west and northwest, producing severe weather on 26-27 May and flash flooding on 28 May. The severe weather potential was recognized on 26-27 May but the flash flood potential was a bit less intuitive on 28 May. Most events were warned with decent lead times, but the convective mode had to be analyzed each day as conditions changed and the frontal boundary slowly shifted east each day.
Above: Soundings from Albany, NY at 12Z and 18Z 26 May and 00Z 27 May. Note the instability and shear through the day.
Above: Upper air charts for 250 hPa, 500 hPa and 850 hPa from 12Z 26 May. Note the upper impulse was not positioned to track east very quickly.
Above: Loop of surface maps from 26 May. Note the front became nearly stationary over northern and western NY.
Above: Storm reports for 26 May.
Above: Pictures of hail from Long Lake.
Above: Soundings from Albany, NY at 12Z 27 May and 00Z 28 May. Note the similar instability and shear to the previous day.
Above: Storm reports from 27 May.
Above: Soundings from Albany, NY at 12Z 28 May and 00Z 29 May. Note the similar instability and shear to the past 2 days. The depth of the moisture increased significantly between 12Z and 00Z.
Above: Radar estimated rainfall. Notice the extreme values in Warren County NY from training thunderstorm cells.
Above: Hydrograph from the Schroon River at Riverbank showing the rapid rainfall runoff that produced flooding.
Above: Storm reports for 28 May. Note large hail was reported along with the flooding rains in Warren County NY.
Above: Pictures from Warren County courtesy of Amy Manning.