Subseasonal Predictions of Polar Low Activity Using a Hybrid Statistical‐Dynamical Approach

Abstract

Polar lows (PLs) are intense maritime mesocyclones that occur during the winter season over high-latitude oceans (Rasmussen & Turner, 2003) with average horizontal length scales on the order of 300 km and lifetimes around 20 hr (Stoll, 2022). PLs can serve as major threats to human life and property through their associated severe weather conditions, such as gale-force winds, large-amplitude oceanic waves (Rojo et al., 2019), and heavy snowfall (Harrold & Browning, 1969). This motivates the skillful prediction of PL activity at short to extended lead times.Forecasting PLs is a challenging task because PLs are short-lived mesoscale systems that develop quickly in sparsely observed oceans (Moreno-Ibáñez et al., 2021). Our short-term prediction capabilities have increased substantially in recent decades, with skillful predictions of storm track and intensity now being realized several days ahead (Müller et al., 2017;Stoll et al., 2020). On the other hand, PL predictability on the subseasonal time scale is yet to be studied, and subseasonal forecasts of PL activity are seldom issued, if at all. The subseasonal variability of PL activity has received some attention and been linked to certain modes of climate variability, including the Madden-

Modulation of Polar Low Activity by the Madden‐Julian Oscillation

“…Although coarse‐resolution global models do not realistically represent PLs, the MJO and the associated teleconnection patterns can be skillfully predicted by global models (e.g., Lim et al., 2018; Robertson and Vitart, 2018; Stan et al., 2022). Since the impacts of the MJO on PL activity can be explained by the large‐scale environmental conditions, skillful subseasonal prediction of PL activity is achievable to the extent that the MJO and the associated teleconnections are predictable on the subseasonal timescale (Boyd et al., 2023).…”

Polar low research: recent developments and promising courses of research

“…In the Bering Sea, Sea of Okhotsk, and Gulf of Alaska, PL activity increases during the Arctic low regime, and decreases during the Pacific wave train regime (Boyd and Wang, 2024). A promising method to produce subseasonal forecasts of PL activity is the PGI (Boyd et al, 2023;Boyd and Wang, 2024), but its forecasting skill depends on the region, with predictability being highest over the Nordic, Irminger, Labrador, and Bering Seas (Boyd et al, 2023).…”