A very warm period is foreseen for northern Europe after this weekend. Temperatures up to almost 10 °C above average for early September are possible across parts of Finland.

As mentioned in the weekly preview yesterday, the European continent is undergoing a significant pattern change this weekend. A so-called Rex blocking ridge pattern develops: a persistent strong ridge / high pressure system over north Europe with an upper low to its south in the Mediterranean. Strong warm advection will be ongoing along the eastern flank of deep trough over the north Atlantic onto Scandinavia. This then brings stable and warm weather into N-NE European countries and much warmer afternoons than usual.

Warm weather is expected to continue for several days before a new wave pushes across the northern Europe from the west. Attached maps are temperature anomalies for Monday, Tuesday and Wednesday afternoons.

These are the peak afternoon temperatures expected on Monday, Sept 3rd. South-central Finland and Sweden could peak into mid 20s which is 8-10 °C warmer than normal for this time of the year.