Quantifying intra-regime weather variability for energy applications

TL;DR

This paper emphasizes the importance of intra-regime weather variability within large-scale atmospheric circulation states, demonstrating how continuous indices can improve energy-related weather forecasts and applications.

Contribution

It introduces a method to quantify intra-regime variability using continuous indices, enhancing the understanding and operational use of weather regimes for energy applications.

Findings

Intra-regime variability significantly impacts surface weather predictions.

Continuous regime indices capture subflavors of circulation states.

Guidance provided for operational interpretation of regime forecasts.

Abstract

Weather regimes describe the large-scale atmospheric circulation in the mid-latitudes in terms of a few circulation states that modulate regional surface weather. Subseasonal forecasts of prevailing weather regimes have proven skillful and valuable to energy applications. Previous studies have mainly focused on the mean surface weather associated with a regime. However, we show in this paper that variability of surface weather within a regime cannot be ignored. These intra-regime variations, caused by different `subflavors' of the same regime, can be captured by continuous regime indices and allow a refined application of weather regimes. Here we discuss wintertime temperature and wind speed regime anomalies for four selected countries, and provide guidance on the operational use and interpretation of regime forecasts. In an accompanying supplementary dataset we provide similar analysis for all European countries, seasons and key energy variables, useful as an applied reference.