New gridded daily operational map products for Slovakia

New gridded climatological maps were added into daily operation at Slovak Hydrometeorological Institute (SHMI) during March 2025. They comprise the following products: Minimum, Maximum, Mean daily air temperature [°C], Daily precipitation sum [mm] and Daily sum of potential evapotranspiration [mm]. The maps are updated daily at 10 a.m. (CET) and are freely available for the public. The temperature maps are created using method of Frei (2014) which is suitable for areas with complex orography since it has been originally used for territories of Switzerland and Austria. Precipitation map is created using two-step interpolation procedure. In this case, the computation combines background monthly normal precipitation fields created by kriging with external drift (KED) and daily field created by Inverse Distance Weighting (IDW) method. Daily sum of potential evapotranspiration is derived from aforementioned maps using modified Hargreaves method (Droogers & Allen 2002). The map products are published at the website in a user-friendly form. E.g. tooltip helps to read the exact interval values from the map to ensure a correct understanding of colour scale used in the maps. Additionally, a videotutorial explaining each product and all its utilities should improve the overall understanding of displayed data by general public.

In consequence, to daily operational climatological maps, newly updated drought monitoring products were added to operation during June 2025. Following products were updated, or newly created: Standardized precipitation-evapotranspiration index (SPEI), Standardized Precipitation Index (SPI), both for 30-day period, Precipitation balance in comparison with normal of 90-day precipitation sum, Percentual difference of precipitation in comparison with normal of 90-day precipitation sum and duration of drought. SPEI and SPI indices include a 7-day forecast based on A-LAEF (days 1-3) and ECMWF IFS models (days 4-7). Instead of a deterministic forecast, an ensemble forecast is used, showing the mean, 10th, and 90th percentiles of the ensemble to illustrate the forecast uncertainty.

Third part of new products represents new bioclimatological products, namely Universal Thermal Comfort Index (UTCI) and Heat index (HI) and fire risk products, namely Fire Weather Index (FWI) and Fuel moisture index (FMI). These products have 7 day forecast as well, based on ALADIN NWP model with 2 km resolution (day 1-3) and ECMWF model (day 4-7).

Acknowledgment

This work was supported by project Clim4Cast (Central European Alliance for Increasing Climate Change Resilience to Combined Consequences of Drought, Heatwave, and Fire Weather through Regionally-Tuned Forecasting; CE0100059) co-funded by European Union funds (ERDF – Interreg Central Europe).