Feedbacks of Sea Surface Temperature to Wintertime Storm Tracks in the North Atlantic

In this study, the lagged maximum covariance analysis is performed on winter storm-track anomalies,
represented by the meridional heat flux by synoptic-scale (2–8 days) transient eddies and sea surface temperature
(SST) anomalies in the North Atlantic, which are both derived from reanalysis datasets spanning
the twentieth century. The analysis shows significant seasonal and interannual coupling between storm-track
and SST variations. On seasonal time scales, it is found that SST anomalies in the preceding early winter
(November–December), which are expected to change the lower-tropospheric baroclinicity, can significantly
influence storm tracks in early spring (March); that is, an intensification and slight northward shift of storm
tracks in response to a midlatitude SST dipole, with a cold pole centered to the southeast of Newfoundland
and a warm pole in the western subtropical Atlantic. This storm-track response pattern is similar to the storm-track
forcing pattern in early spring, which resembles the dominant mode of storm tracks. At interannual
time scales, it is found that the wintertime (January–March) storm-track and SST anomalies are mutually
reinforced, manifesting as a zonal-dipole-like pattern in storm-track anomalies (with dominant negative
anomalies in the downstream) coupled with a midlatitude SST monopole (with warm anomalies centered to
the south and east of Newfoundland).