Status:Ongoing analysis Material from: Linus, Esti, Ivan, ..
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Discussed in the following Daily reports: |
1. Impact
During the last week of February large parts of Europe were hit but a strong cold spell. The temperatures reached -40C in Scandinavia and below -10C in southern England, and Rome was hit by unusual snowfall. At the same time northern Greenland experienced extremely warm temperatures. The cold spell was due a very strong negative NAO period that might be linked to a sudden stratospheric warming and/or MJO in phase 6/7.
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The plot below shows the time evolution of temperature anomalies over the Arctic (north of 70N). The onset of the stratospheric warming took place around 11 February.
The plot below show the observed anomalies from 26 February to 4 March 2018 with respect to 15-year observed climatology (left), OBS < Q5 (blue) and OBS > Q95 (red) (middle) and OBS < Q1 (blue) and OBS > Q99 (red) (right).
3. Predictability
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The plots below show weekly anomalies of 2-metre temperature for 26 February to 4 March.
The plots below show weekly anomalies of mean-sea-level-pressure for 26 February to 4 March. The negative NAO pattern was captured from 5 February and onwards, which coincides with capturing the stratospheric warming as seen above.
The figure below shows the EFI for the weekly mean of 2-metre temperatures.
The plot below show MJO forecasts from 29 January to 15 February.
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