*Article NeXtNow***: A Convolutional Deep Learning Model for the Prediction of Weather Radar Data for Nowcasting Purposes**

**Alexandra-Ioana Albu 1,†, Gabriela Czibula 1,\*,†, Andrei Mihai 1,†, Istvan Gergely Czibula 1,† and Sorin Burcea 2 and Abdelkader Mezghani 3**

> 1 Department of Computer Science, Babe¸s-Bolyai University, 400084 Cluj-Napoca, Romania;

alexandra.albu@ubbcluj.ro (A.-I.A.); andrei.mihai@ubbcluj.ro (A.M.); istvan.czibula@ubbcluj.ro (I.G.C.) 2 Romanian National Meteorological Administration, 013686 Bucharest, Romania;


**Abstract:** With the recent increase in the occurrence of severe weather phenomena, the development of accurate weather nowcasting is of paramount importance. Among the computational methods that are used to predict the evolution of weather, deep learning techniques offer a particularly appealing solution due to their capability for learning patterns from large amounts of data and their fast inference times. In this paper, we propose a convolutional network for weather forecasting that is based on radar product prediction. Our model (*NeXtNow*) adapts the ResNeXt architecture that has been proposed in the computer vision literature to solve the spatiotemporal prediction problem. *NeXtNow* consists of an encoder–decoder convolutional architecture, which maps radar measurements from the past onto radar measurements that are recorded in the future. The ResNeXt architecture was chosen as the basis for our network due to its flexibility, which allows for the design of models that can be customized for specific tasks by stacking multiple blocks of the same type. We validated our approach using radar data that were collected from the Romanian National Meteorological Administration (NMA) and the Norwegian Meteorological Institute (MET) and we empirically showed that the inclusion of multiple past radar measurements led to more accurate predictions further in the future. We also showed that *NeXtNow* could outperform *XNow*, which is a convolutional architecture that has previously been proposed for short-term radar data prediction and has a performance that is comparable to those of other similar approaches in the nowcasting literature. Compared to *XNow*, *NeXtNow* provided improvements to the critical success index that ranged from 1% to 17% and improvements to the root mean square error that ranged from 5% to 6%.

**Keywords:** weather nowcasting; deep learning; ResNeXt; radar data
