Heat extremes frequently hit different regions synchronously during boreal summer over the Eurasian continent. A remarkable coupling is first revealed between Eurasian heat extreme occurrence and individual extratropical intraseasonal oscillation (EISO). Further, the combined EISOs facilitate and largely increase the occurrence probabilities of synchronous Eurasian heat extremes. These dominant combined EISOs together contribute 20–45% to the total heat extreme days over the five Eurasian regions where the climatological heat extremes occur most frequently. A multi-model hindcast further shows that the subseasonal prediction exhibits higher skills for synchronous heat extremes over the combined-EISO hotspot regions when the associated combined EISOs are active, supporting the notion that the monitoring and prediction of EISOs are crucial for heat extremes’ early warning. Skillful prediction of EISOs opens a pathway for heat extremes’ prediction by extending it from the weather to the subseasonal timescales.

在北半球夏季，欧亚大陆的不同地区经常同时遭遇极端高温。首次揭示了欧亚极端高温事件与个别温带季节内振荡（EISO）之间的显着耦合。此外，组合的 EISO 促进并大大增加了同步欧亚高温极端事件的发生概率。这些占主导地位的综合 EISO 合计占极端高温天气最频繁发生的欧亚五个地区极端高温日总数的 20-45%。多模型后报进一步表明，当相关的组合 EISO 活跃时，次季节预测对组合 EISO 热点区域的同步极端高温表现出更高的技能，支持了 EISO 的监测和预测对于早期极端高温至关重要的观点。警告。 EISO 的熟练预测通过将其从天气扩展到次季节时间尺度，为极端高温的预测开辟了一条途径。