An extraordinary and unprecedented heatwave swept across western North America (i.e., the Pacific Northwest) in late June of 2021, resulting in hundreds of deaths, a massive die-off of sea creatures off the coast, and horrific wildfires. Here, we use observational data to find the atmospheric circulation variabilities of the North Pacific and Arctic-Pacific-Canada patterns that co-occurred with the development and mature phases of the heatwave, as well as the North America pattern, which coincided with the decaying and eastward movement of the heatwave. Climate models from the Coupled Model Intercomparison Project (Phase 6) are not designed to simulate a particular heatwave event like this one. Still, models show that greenhouse gases are the main reason for the long-term increase of average daily maximum temperature in western North America in the past and future.

Using multiple-satellite datasets, in situ observations, and numerical simulations, the influence of typhoon-induced precipitation on the oceanic response to Typhoon Kalmaegi has been discussed. It is found that the convective system and precipitation distribution of Kalmaegi was asymmetric, which leaded to the asymmetric rainfall at observational stations. The sea surface salinity (SSS) of the buoy to the right of storm track increased with a 0.176 practical salinity units (psu) maximal positive anomaly, while the two buoys on the left side underwent several desalination processes, with a maximum decreases of 0.145 psu and 0.278 psu. Numerical simulations with and without precipitation forcing were also performed. Model results showed that typhoon-induced precipitation can weaken sea surface cooling by approximately 0.03–0.40 °C and suppress the SSS increase by approximately 0.074–0.152 psu. The effect of precipitation can be divided into the direct effect and indirect effect. On one hand, freshwater from precipitation directly dilutes the salinity. On the other hand, when salinity decreases, the ocean stratification will be enhanced, the vertical mixing will be restrained, and then the temperature and salinity can be further affected by weakened vertical mixing.

The trend of tropical-cyclone (TC) translation speed is a hot topic recently. Changes in TC translation speed during 1949–2017 over the western North Pacific are analyzed using two best-track datasets here. The TC translation speed decreased during 1949–2017, but there was no significant trend after 1981. The TC translation speed also changes with latitude and intensity. In the tropical ocean, TC translation speed decreased by 5.9% during 69-year recording period. North of 23.5° N, the changes in translation speed is highly consistent with the latitude of TC occurrence. The translation speed of tropical depressions showed no significant trend during the period 1949–2017, but the translation speed of typhoons decreased over the 69-year recording period. The period 1949–1981 contributed most of the slowdown trend. There also was an increase in the frequency of typhoons with translation speed slower than 6 m/s. The decrease of translation speed of typhoons before 1981 was likely caused by the weakening of the summertime tropical circulation.

Western Europe experienced an unprecedentedly hot July in 2022, which significantly impacted ecosystems and society. Our observational and numerical modeling study reveals that this event was influenced by anomalous North Atlantic and Eurasian jet streams. The northeastward shift of the North Atlantic jet stream, driven by sea surface temperature gradients, and the curving of the Eurasian jet stream, affected by rainfall anomalies in Pakistan, enhanced atmospheric subsidence over western Europe. This research highlights the crucial role of the synergistic behavior of the North Atlantic and Eurasian jet streams in driving extreme heat over Western Europe. Furthermore, CMIP6 climate model projections suggest that under the SSP585 scenario, similar jet stream configurations could lead to even more intense extreme temperatures (~7.02 ± 0.61 °C) compared to the current climatological mean.