Persistent temperature anomalies during blocking high-pressure events arise from a combination of large-scale dynamical stagnation and surface-atmosphere feedbacks that reinforce heating or cooling beneath the ridge. Research that attributes blocking to quasi-stationary wave patterns emphasizes how disrupted west-to-east flow allows a persistent anticyclone to deflect normal storm tracks and air-mass exchange. Thomas Woollings University of Oxford has shown that Rossby wave breaking and changes in the jet stream shape are central to block formation, producing the slow-moving ridges that trap air masses for days to weeks.
Dynamical drivers and surface feedbacks
Inside the high-pressure core, subsidence warming compresses and heats descending air while clouds thin, increasing incoming solar radiation and daytime heating. Reduced horizontal advection under a stationary ridge means local thermodynamic processes, not frontal exchange, dominate temperature evolution. Soil moisture feedback is a powerful amplifier: when soils are dry, less incoming energy goes into evaporation and more into sensible heating, raising surface temperatures further. Sonia Seneviratne ETH Zurich has documented how soil moisture deficits amplify heatwave intensity and persistence, linking land-surface state to atmospheric extremes. Arctic and snow-cover anomalies can also alter albedo and regional heating, with researchers such as David W. J. Thompson Colorado State University highlighting how shifts in high-latitude forcing can influence jet latitude and block susceptibility, though the magnitude and sign of these links remain subjects of active study.
Consequences and regional nuance
Prolonged temperature anomalies beneath blocking highs have direct human, ecological, and economic consequences. Heat extremes stress public health systems, reduce crop yields, and increase energy demand; in dry regions they raise wildfire risk and strain water supplies. Cold anomalies on the poleward side of some blocks can cause damaging freezes that affect agriculture and infrastructure. Cultural and territorial factors shape vulnerability: urban heat islands and densely populated Mediterranean basins amplify human exposure to stuck heat, while boreal forest regions face heightened fire risk and carbon feedbacks. Jennifer A. Francis Woodwell Climate Research Center has argued that changing Arctic conditions may influence the frequency or persistence of these patterns, a hypothesis that motivates ongoing model and observational work.
Improving forecasts and adaptation depends on better representation of wave-mean flow interactions, land–atmosphere coupling, and cryosphere variability in models, and on targeted monitoring of soil moisture, snow cover, and regional circulation to anticipate the onset and societal impacts of blocking-driven temperature anomalies.