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Maximum CAPE during the specified period is shown as well as maximum CAPE in case the convective inhibition (CIN) is less than 200 J/kg and therefore convection can be triggered. When CIN is greater than 200 j/kg the cap is so strong that it prevents convection from happening.
The tephigram for Varna, the city affected by flash floods, shows that the atmosphere was unstable, humidity quite high coming from the Black Sea with easterly winds at the surface. The black curve in the analysis is drawn taking the maximum temperature in Varna on that day which was close to 23C. The 12-hour forecast profile was a little bit different with a deep saturated layer from the surface implying rainfall at that time.
Tephigrams for Varna: analysis (left), 12-h forecast (right).
3.3 ENS
The flash floods occurred on 19 June in the evening and in early morning on the 20 June when just in few hours more than 100 mm of rainfall were recorded in NE part of the country. Flash floods occurred there. The analyses show that 99th model climate percentile for 24h total rainfall was exceeded in many places in the east of Bulgaria. Some local heavy showers were observed in far western regions of the country as well. If we compare observations with the 95th model climate (M-climate) percentile, we'll notice areas of local torrential downpours in many parts of Northern Bulgaria as well. The shortest range EFI forecast matches quite well the areas affected by heavy rain but the EFI has never reached extremely high values close to 1 over NE Bulgaria. This is more likely due to the convective nature of the rain and the large uncertainty in the forecast that we might expect in such cases. Note that there is 6-hour shift between the validity of the EFI forecast and the accumulations represented by the observations: EFI is valid from 00 to 00UTC whilst accumulations are for periods starting from 06UTC.
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Longer lead time EFI/SOT forecasts for 72- and 120-hour total precipitation. Green triangles denote observations that exceed 99th model climate percentile.
The extended-range EFI, for T+240-360 gives a hint of wet weather.
EFI for total precipitation, forecast for T+240-360h. Yellow/red colours mean wetter than normal conditions.
3.4 Monthly forecasts
Exceptionally wet weather in the Balkans has been predicted well in the medium range by the ENS. Positive precipitation anomalies appeared even in the far medium range for days 8 to 14. For longer ranges in the monthly forecast there is no signal.
Precipitation anomalies from ECMWF monthly forecast compared with the analysis.
3.5 Comparison with other centres
Four control forecast of total precipitation from TIGGE: ECMWF, UKMO, NCEP and LAM Aladin Austria. Having different resolution and different model characteristics they all forecast significant rainfall in the eastern part of Bulgaria.
4. Experience from general performance/other cases
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