A shot of unseasonably cool air is headed for northwestern Europe early this week.
The core of the chill will be felt on Tuesday as temperatures will not rise above 20 C (68 F) across northern France and Germany, Great Britain, Belgium and the Netherlands. This will be 3-5 degrees C (5-9 degrees F) below average in many areas.
A high of 18 C (64 F) in London on Tuesday will be the coolest day in over 2 months. The city had a similar high on June 16. The low temperature in London will fall below 10 C (upper 40s F).
While this is not a large departure from average, this region has averaged above-normal temperatures since the beginning of June. London, England for example, has averaged 2 C (4 F) above normal through this time.
In addition to below-average temperatures, showers will cross northern Europe. Cold air aloft will lead to instability bring the threat for some thunder across Scandinavia as well.
Temperatures will warm slightly through the rest of the week in these areas, but it will still remain showery and a little cooler than what can be expected this time of year.
The low pressure system that brought showery and blustery conditions this weekend across the United Kingdom, northern France and Germany is also responsible for this cool air. As the low stalls across Scandinavia this week, it will bring a brisk northerly flow across the region providing the cooler conditions.
Across central and southern Europe, a cold front will separate the cooler air across northern Europe from continued warmth across the Balkans and Ukraine.
High temperatures in these areas will be in the upper 20s and lower 30 C (middle to upper 80s F). This is generally 2-5 degrees C (4-9 degrees F) above average. Like much of northern Europe, with the exception of Greece and Bulgaria, much of southeastern Europe was been warmer than average since June.