Synoptic Typing of Multiduration, Heavy Precipitation Records in the Northeastern United States: 1895–2017

Abstract

Much of the previous research on total and heavy precipitation trends across the Northeastern US (hereafter Northeast) used daily precipitation totals over relatively short periods of record, which do not capture the full range of climate variability and change. Less well understood are the characteristics of long-term changes and synoptic patterns in longer-duration heavy precipitation events across the Northeast. A multi-duration (1, 2, 3, 7, 14, and 30 days), multi-return interval (2, 5, 10, and 50 years) precipitation dataset was used to diagnose changes in various types of precipitation events across the Northeast from 1895 to 2017. Increasing trends were found in all duration and return-interval event combinations with the rarest, longest duration events increasing at faster rates than more frequent, shorter duration ones. Daily 850-hPa geopotential height patterns associated with precipitation events were extracted from Rotated Principal Component Analysis and k-means clustering analysis, which allowed for the main synoptic types present, as well as their structure and evolution to be analyzed. The daily synoptic patterns thus identified were found to be similar across all durations and return-intervals and included: coastal low (Nor’easters, tropical cyclones, and predecessor rain events), deep trough, east coast trough, zonal, and high pressure patterns.

Contributions of Tropical Cyclones and Atmospheric Rivers to Extreme Precipitation Trends Over the Northeast US

“…Extreme precipitation, both the intensity and frequency, has increased across much of the contiguous United States since the 20th century (e.g., Anderson et al, 2015;DeGaetano, 2009;Easterling et al, 2017;Hoerling et al, 2016;Janssen et al, 2014;Kunkel et al, 2013;Min et al, 2011). The Northeast US (NEUS; all acronyms used in this paper are listed in Table S1 in Supporting Information S1), the most populated region in North America including the Boston to DC metro corridor area, has experienced the most rapid increase in the frequency of extreme precipitation in the US, especially since the mid-1990s (e.g., Brown et al, 2010;Crossett et al, 2023;DeGaetano, 2009;DeGaetano et al, 2020;Frei et al, 2015;Guilbert et al, 2015;Hoerling et al, 2016;Howarth et al, 2019;Huang, Patricola, Winter, et al, 2021;Huang et al, 2017Huang et al, , 2018Jong et al, 2023;Olafdottir et al, 2021). Extreme precipitation frequency over the NEUS, moreover, is projected to increase in the future warming climate (e.g., DeGaetano & Castellano, 2017;Hayhoe et al, 2007;Jong et al, 2023;Nazarian et al, 2022;Ning et al, 2015;Picard et al, 2023).…”