Status: Ongoing analysis Material from: Linus
1. Impact
In August 2021 the Mediterranean saw extreme temperatures. In the beginning of the month severe wildfires hit Greece and Turkey. On 11 August the European temperature record was broken in Syracuse on Sicily with 48.8C. Later the heatwave continued to the Iberian peninsula with temperatures of 46.9C in Cordoba on 14 August.
2. Description of the event
The plots below show analyses for z500 and T850 from 5 August to 16 August.
The plot below shows Howmoller diagram of T850 analyses averaged between 30-45N. The most recent days are on the top, with the heatwave propagating from east to west over the Mediterranean.
3. Predictability
3.1 Data assimilation
3.2 HRES
3.3 ENS
The plots below show EFI for 2-metre maximum temperature on 11 August, with a 1x1 degree box centred over Syracuse.
The plot below shows the forecast evolution for 1-day (11 August) maximum temperature inside the black box outlined above (centred on Syracuse). The plot includes HRES (red), ENS control (purple), ENS distribution (blue box-and-whisker) and model climate (red box-and-whisker). The black triangle indicate model climate maximum. The signal for the heatwave started to appear around 29 August, but retreated in forecasts around 2 August before the signal got stronger again. From 5 August and onwards all ensemble medians were above the model climate maximum. One can note that the HRES was consistently warmer than ENS CF in the short-range.
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The plots below show EFI for 2-metre maximum temperature on 14 August, with a 1x1 degree box centred over Cordoba.
The plot below shows the forecast evolution for 1-day (14 August) maximum temperature inside the black box outlined above (centred on Cordoba). The plot includes HRES (red), ENS control (purple), ENS distribution (blue box-and-whisker) and model climate (red box-and-whisker). The black triangle indicate model climate maximum. All extended-range forecasts where above normal temperature, and the signal gradual increased from 31 July.
3.4 Monthly forecasts
The plot below show weekly ensemble mean anomalies of 2-metre temperature valid 9-15 August from different initial dates. While Sicily and central Spain was warmer than normal in the forecast from 2 August, the large-scale structure of the heatwave was missed in this forecast.
