Downpours will spread from Italy to Ukraine to start the weekend before cooler air works southward and eventually sweeps the heat wave away from the Balkan Peninsula.
While a prolonged cool spell is already underway across the northern half of Europe, the Balkan Peninsula is facing additional days of sizzling heat Friday and Saturday.
Temperatures will once again soar toward or past 32 C (90 F) across most of the Balkans on Friday and Saturday. This includes in Belgrade, Sofia and Bucharest. More typical early-September highs range from near 24 C (75 F) in Sofia to around 27 C (lower 80s F) in Bucharest.
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).
Relief from the heat is finally on the horizon for Sunday and Monday with the passage of a cold front, but that will not happen until an area of low pressure riding along the front tracks from Italy to Ukraine accompanied by potentially flooding downpours.
The drenching rain and thunderstorms will first evolve around Rome late Friday night. While flash flooding is the greater threat, there is concern that the strongest thunderstorms will be able to kick up damaging winds.
As the soaking persists into Saturday morning in Rome, downpours will unfold during the day across the northwestern Balkans. This includes in Slovenia, Croatia, northern Bosnia and Herzegovina, northern Serbia, southern Hungary and northwestern Romania.
Saturday night, the drenching rain will spread to Kiev and neighboring parts of Belarus.
Localized flooding will remain a threat as the downpours shift eastward Saturday into Saturday night. Even if flooding does not ensue, the heavy rain could create issues for travelers by reducing visibility and heightening the risk of vehicles hydroplaning at highway speeds.
Those with outdoor plans to start the weekend may be forced to postpone them or move indoors.
Once the downpour threat shifts out of the Balkans, the door will open for the storm system's cold front to drop southward and finally sweep away the seemingly unrelenting heat wave.
The cooling will come in a north-to-south fashion Sunday into Monday, causing temperatures to be held 6 to 12 degrees C (10 to 20 degrees F) below the previous day's high. Monday's highs surpassing 32 C (90 F) will be suppressed to southern Greece with no indication of a quick return to the rest of the Balkans in the following days.