Or Hadas and Yohai Kaspi of the Weizmann Institute of Science published "Stronger jet, weaker storms: a mechanistic perspective on the Atlantic-Pacific storm paradox" in Nature Communications at 01:26 UTC Wednesday, April 22. [1] The paper uses 84 years of ERA5 reanalysis data and winter storm tracks to argue that the stronger-jet, weaker-storm paradox that has sat open since Nakamura's 1992 paper on Pacific midwinter suppression can be explained by a single mechanism: jet orientation.

The Pacific jet stream is stronger than the Atlantic jet in winter. Atlantic storms are nonetheless more intense. The authors find the Pacific jet's more zonal orientation moves storms through the baroclinic growth zone faster than they can extract kinetic energy from the mean flow, while the Atlantic jet's tilted orientation — from southwest to northeast — aligns with storm trajectories and gives them a longer runway along the growth zone. "Stronger jets" and "weaker storms" stop contradicting each other once the geometry of the jet relative to the storm track is included.

The implication goes beyond the academic puzzle. Hadas and Kaspi's earlier 2024 Journal of Climate paper linked storm intensity to Earth's albedo through cloud cover. [2] If jet orientation controls storm intensity and storm intensity controls cloud-radiative effects, then climate models that reproduce jet strength without reproducing jet orientation will get the wrong albedo under warming. The Pacific jet is expected to strengthen in a warming climate; the Atlantic jet is expected to tilt less. [1] Both effects would reduce storm intensity in the two basins — in which case midlatitude weather loses a central source of cloud cover just as the climate needs more of it. The paper does not run those projections. It makes them necessary.

-- KENJI NAKAMURA, Tokyo