Time of measurement is shown in UTC (UTC = UT = GMT = CEST-2h = CET-1h), local time is shown in parentheses after UTC time.

Radar data
Radar data include combined information from Skalky and Brdy radar. Area with no available radar data is covered by grey color.
The description of reflectivity scale with precipitation intensity in [mm/h] is only approximate. The scale demonstrates exponential dependence of precipitation intensity [mm/h] on radar reflectivity [dBZ]. For low precipitation intensities (approx. 0.1 mm/h) the precipitation often doesn't reach the ground. For high precipitation intensitites (over 100 mm/h) the actual precipitation intensity is often lower, these values rather imply the presence of hail, which are the strongest targets of meteorological origin.
Narrow colourful rays that don't represent any real radar target are sometimes present in radar data. Their origin isn't meteorological but they are related to the jamming of radar measurements by wireless communication network devices operated by internet providers. Intensity of these "targets" varies between individual measurements (approx. 4 - 30 dBZ), sometimes it can even vanish.
More detailed information is available on ZDE.

Lightning detection
Lightning flash is a strong spark discharge, when electric charge is transferred between places with different electric potential. Lightning flashes can be classified as intracloud (IC) and cloud-to-ground (CG) flashes, which can be further classified as negative (CG-, carrying negative charge into ground) and positive (CG+, carrying positive charge into ground). CHMI doesn't operate own lightning detection network but it utilizes data from lightning detection network operated by external company. Detection network is mainly suitable for detection of CG flashes, probability of detection in case of IC flashes is lower. Network detects individual lightning discharges, whereas lightning flash usually consists of several lightning discharges. Probability of detection of individual lightning discharges is approx. 70%, probability of detection in case of lightning flashes (i.e. at least some part of lightning discharges) should exceed 90% but it is not 100%. Spatial accuracy of network is approx. 1 km. On rare occasions false lightning discharges can be detected.

Precipitation 1h, 3h, 6h, 24h
Areal radar precipitation estimates and point values obtained from station precipitation measurements are summed over 1h, 3h, 6h, 24h and then combined together. The resulting field has advantages of both methods: the spatial coverage by radar measurements as well as precise direct point measurements on meteorological stations. However, even these combined precipitation estimates can be burdened by inaccuracies - missing station measurements or their insufficient representation of given area, radar beam attenuation, orgraphic intensification of precipitation, etc.

Station measurement
Application displays hourly measurements from meteorological stations.

Author: RNDr. Petr Novák Ph.D., Czech Hydrometeorlogical Institute.