The Influence of Atmospheric Rivers on Cold‐Season Precipitation in the Upper Great Lakes Region

Abstract

This study aims to identify the impacts of atmospheric rivers (AR) associated with cold‐season precipitation in the Upper Great Lakes region of the United States. A MERRA‐2‐derived AR dataset is combined with data from a suite of instruments hosted by the National Weather Service in Marquette, Michigan, including a profiling radar and a video disdrometer. ARs coincide with deep, synoptically‐forced precipitation 28% of the time during the cold season. These ARs are found to intrude from the southwest and are associated with warmer surface and upper‐level temperatures, increased radar reflectivity values, and enhanced precipitation rates. Warmer atmospheric temperatures aloft associated with ARs lead to a fourfold increase in the likelihood that cold‐season precipitation will be rain instead of snow. Additionally, inland ARs in the Upper Great Lakes region are correlated with the negative phases of the Pacific Decadal Oscillation and the Pacific‐North American pattern.

Multi‐Year Analysis of Rain‐Snow Levels at Marquette, Michigan

“…The rain and RSL identification starts with a threshold for precipitation occurrence of radar reflectivity greater than −10 dBZ at the 400 m AGL (Kulie et al., 2021; Mateling et al., 2021; Pettersen, Kulie, et al., 2020; Shates et al., 2021). Next, rain and snow are separated using a V d threshold (White et al., 2002) where rain is conservatively categorized as having V d greater than 3 ms −1 .…”

“…The Great Lakes Region also experiences precipitation from atmospheric rivers (Mateling et al., 2021; Slinskey et al., 2020), and Mateling et al. (2021) illustrated that atmospheric river events impact the MQT site and often lead to enhanced precipitation rates and cold‐season rain events.…”

“…RSLs respond to the seasonal change in temperature. During the cold season, most precipitation falls as snow at MQT, but Mateling et al (2021) showed that atmospheric river events reaching the site increase the likelihood of rainfall. Surface air temperatures associated with many shallow RSL rainfall events were also near 0°C (not shown), which further underlines the challenge in using a temperature threshold to separate snow, rain-snow transitions, and freezing rain (Stewart et al, 2015) within the satellite radar blind zone.…”

“…Kulie et al (2021) further characterized MQT snowfall regimes, including enhancements of shallow and deep snowfall from the effects of orography and Lake Superior. The Great Lakes Region also experiences precipitation from atmospheric rivers (Mateling et al, 2021;Slinskey et al, 2020), and Mateling et al (2021) illustrated that atmospheric river events impact the MQT site and often lead to enhanced precipitation rates and cold-season rain events.…”

Vertical Structure of Clouds and Precipitation During Arctic Cold‐Air Outbreaks and Warm‐Air Intrusions: Observations From COMBLE

“…The median date of occurrence of CAOs fell on 13 March 2020, and that of WAIs fell on 08 February 2020. Reanalysis‐based climatologies show that CAOs are most common in the winter (DJF) over the far northern Atlantic Ocean (Fletcher et al., 2016; Mateling et al., 2023). The seasonal contrast probably is smaller for WAIs, but their impact is most pronounced in winter (Woods & Caballero, 2016).…”