On Sunday, downpours will spread across areas from the Adriatic Sea to western Ukraine as cooler air is ushered into the Balkans. These downpours will be the dividing line between cooler and unsettled conditions in the northern half of Europe, and hot conditions in the southern Balkans.
Temperatures highs in Greece will still soar to near 38 C (100F) on Sunday, but areas further to the north will feel the cooler air moving into the region. Athens is expected to reach 37 C (99 F) on Sunday, but not too far to the north, Sarajevo will only see a high of 20 C (68 F).
Residents will have to continue to use caution outdoors to avoid suffering from heat exhaustion or stroke. Drink plenty of water, wear light clothing and avoid strenuous activity during the hottest time of the day (the midday and afternoon hours).
A more typical high in Athens in early September is near 29 C (85 F). Temperatures will begin to slowly fall on Monday in the city, but will remain hotter than average, More seasonable conditions will finally arrive by Tuesday and will last into the end of the week.
Where the cooler air will be in place, downpours will breakout from Serbia to Ukraine on Sunday. Some of these downpours could bring over 13 mm (0.50 of an inch) within a short period of time causing difficult travel. Although the rain will exit these areas early in the coming week, the cooler conditions will remain.
A persistent trough in the jet stream across the region will continue cooler conditions well into the coming week. This is in contrast to the hot conditions that dominated the Balkans over most of the summer.