The probabilistic skill of extended-range heat wave forecasts over Europe

Loading...
Thumbnail Image

Access rights

openAccess
CC BY
publishedVersion

URL

Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Major/Subject

Mcode

Degree programme

Language

en

Pages

15

Series

Natural Hazards and Earth System Sciences, Volume 25, issue 6, pp. 1865-1879

Abstract

Severe heat waves lasting for weeks and expanding over hundreds of kilometers in the horizontal scale have many harmful impacts on health, ecosystems, societies, and the economy. Under the ongoing climate change, heat waves are becoming even longer and hotter, and, as a proactive adaptation, the development of early warning services is essential. Weather forecasts in the extended range (2 weeks to 1 month) tend to indicate a higher skill in predicting warm extremes than average temperature events in Europe. We verified hindcasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) in forecasting heat wave days, defined here as periods with the 5 d mean temperature exceeding its 90th percentile. The verification was done in 5° × 2° resolution over Europe, based on the forecast week (1 to 4 weeks). In the first forecast week, it is evident that, across Europe, the accuracy of ECMWF heat wave forecasts surpasses that of a climatological forecast. Even into the second week, in many regions in Europe, the ECMWF forecasts prove to be more reliable than their statistical counterparts. However, if we extend the forecast lead time to 3–4 weeks, predictability begins to decline to such a level that it can no longer be said, except for southeastern Europe, that the forecasts in general were statistically significantly better than the statistical forecast. Nonetheless, the persistence of prolonged heat waves seems to have a higher-than-average level of predictability even at a 3-week lead time, offering early warning services an indication of the potential duration of an ongoing heat wave.

Description

Publisher Copyright: © Author(s) 2025.

Keywords

Other note

Citation

Korhonen, N, Hyvärinen, O, Kollanus, V, Lanki, T, Jokisalo, J, Kosonen, R, Richardson, D S & Jylhä, K 2025, 'The probabilistic skill of extended-range heat wave forecasts over Europe', Natural Hazards and Earth System Sciences, vol. 25, no. 6, pp. 1865-1879. https://doi.org/10.5194/nhess-25-1865-2025