I want to take some time to dissect the meteorology and hydrology behind what will be remembered as a defining event in Northeast flood history, one that struck the county where I was born and raised.

(Attached: picture of me at Rich's Farm ice cream in Oxford, in better times) There were essentially three separate extreme rain events yesterday: one in Fairfield County, one in New Haven County, and one in Long Island. The first two were generally from the same meso-boundary and overlapped, though saw a shift in focus; the third was clearly discrete.

More and more confident the Northeast could experience the worst flooding since Ida over the coming 48 hours. For some locations, this could be the most severe hydrological event since Irene. A thread on the setup, the hazard, and why I'm so concerned.

Flooding is a complicated, ingredients- and storm- based thing to forecast. But it all comes down to: will it rain enough to overwhelm natural and manmade water-removal infrastructure? Enough to send streams from banks, swamp urban drains, bust culverts and roads, sink hillsides?

Per an analysis of KBUF ASOS data, Buffalo seems to currently be experiencing the longest duration of continuous blizzard conditions since at least 1950- by a wide margin.

12/24/2022 20:54: 31.25 hours
1/21/1985 21:00: 16.00 hours In 1977, blizzard conditions lasted 'just' 11 continuous hours at most.

Ten years ago today, severe storms tore through the East. They were extremely impactful, enough so to launch the word "derecho" into the national spotlight.

Perhaps the most astounding aspect of that most epic windstorm? Every major record it set has since been shattered.

https://twitter.com/capitalweather/status/1542237587485691910

The decade since has been a broken record of broken records for derecho activity.

6/29/2012 was soaringly historic for 75mph wind gusts, an important metric of derecho activity. But that record was broken in 2020, and again in 2020, and then in 2021, and in 2022.