Data about radar rainfall nowcasts of 80 high-intensity rainfall in 5 cities in the Netherlands from 2008 to 2021

doi: 10.4121/22246273.v1
The doi above is for this specific version of this dataset, which is currently the latest. Newer versions may be published in the future. For a link that will always point to the latest version, please use
doi: 10.4121/22246273
Datacite citation style:
Lin, Steven (2023): Data about radar rainfall nowcasts of 80 high-intensity rainfall in 5 cities in the Netherlands from 2008 to 2021. Version 1. 4TU.ResearchData. dataset.
Other citation styles (APA, Harvard, MLA, Vancouver, Chicago, IEEE) available at Datacite
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This repository contains the radar rainfall nowcasts for 80 high-intensity rainfall events spread over 5 urban areas (Amsterdam, the Hague, Groningen, Maastricht, and Eindhoven) in the Netherlands. 

Rainfall events chosen criteria: 

The high-intensity events were selected for each municipality by using RadarTools ( RadarTools can list the rainfall events based on the highest climatological rainfall accumulation at any 1-km2 grid cell within each municipality in the Netherlands since 2008. RadarTools sets different thresholds to select rainfall events of different periods. For example, the selection criteria for 1-h period is that the precipitation sum in any grid cell is above 15 mm. For 24-h period, the threshold is 30 mm. Rainfall is not necessarily continuous during the period. We selected the eight highest 1-h and eight highest 24-h events in each of the 5 municipalities from 2008 to 2021. When selecting the 24-h events, the events that covered the period of the previously selected 1-h events were excluded per urban area to ensure independence of the events. This selection procedure led to 5 (cities) × 2 (durations) × 8 (events) = 80 events. 


For every five-minute time step in each of the events, a probabilistic nowcast was made by pySTEPS (v0.2 used) libraries (Ayzel et al., 2019; Pulkkinen et al., 2019). 

We used the same Pysteps setup as in Imhoff et al. (2020,, which consisted of the STEPS (short-term ensemble prediction system) nowcasting method using a semi-Lagrangian advection method and the Lucas‐Kanade optical flow method (using the QPE from time t-3 to t). An autoregressive model of order 2 and 8 cascade levels was used. 

All nowcasts have a time step of 5 min and a forecast horizon of 4 hours. Nowcasts are first run with real-time QPE from Royal Netherlands Meteorological Institute ( The 1-h events before 2020 are also run with climatological ( and CARROTS-adjusted QPE ( Hence, in total, there are 9,060 separate norecasts (each with 4-hour forecast horizon and 20 ensemble members). 

The nowcasts are saved as netCDF files in folders with the following structure: event duration (1 or 24 hrs) and QPE products used (realtime, CARROTS, or climatological) > city name > event folder > individual nowcasts. The filenames of the event folder indicate the onsets of the high-intensity rainfall events in UTC. The filenames of nowcasts indicate the issue time of the nowcasts in UTC.

  • 2023-04-17 first online, published, posted
TU Delft, Faculty of Civil Engineering and Geosciences, Department of Water Management
Deltares, Delft
Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands


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