About precipitation forecast table

HHFS receives precipitation forecast data from the Hungarian Meteorological Service twice a day. Forecast data are given on a regular grid which covers all subcatchment areas included in HHFS hydrological forecast system. From incoming precipitation forecast data mean areal values are produced for various time intervals and subcatchments using different methods (including HHFS' own developed downscaling and parameter estimation methods). After data processing phase maps and tables are produced in order to give an adequate representation of the forecasts for hydrological purposes. The meteorological model used by HHFS is run twice a day, namely at 00 UTC and 12 UTC. Products based on the first model run are published on this site shortly after 9 a.m. during summer time (respectively after 8 a.m. in the rest of the year), correspondingly data of the second model run are published after 9 p.m. during summer time (respectively after 8 p.m. in the rest of the year).

"Day 1" in the table header refers to the day of the model run, "06-18" refers to the time interval between 06 UTC and 18 UTC, respectively "18-06" refers to the time interval between 18 UTC and 06 UTC. For example in the forecast table of the model run on 12 July 2008 at 00 UTC, the "Day 1/18-06" column contains mean areal precipitation values expected in the period 12 July 2008 18 UTC - 13 July 2008 06 UTC.

Due to HHFS' continuous development activity mean areal precipitation forecast values are produced not only for main subcatchments, but also for smaller ones which are of crucial importance in runoff processes.

When exceed a certain threshold, forecasted values are displayed in the tables using different colours as listed below:

• forecasted precipitation is expected to be between 15 and 25 mm: yellow
• forecasted precipitation is expected to be between 25 and 50 mm: orange
• forecasted precipitation is expected to exceed 50 mm: red