More pronounced cooling to follow, but it won't mark the complete end of summer

Written by: Nedim Sladić

After a short period of stable days characterized by pleasant and slightly above-average air temperatures, a new deterioration of weather conditions is approaching from Western Europe. Atmospheric pressure will drop in our regions as early as tomorrow. We will owe all of this to a cold front associated with a Genoa cyclone, which will move from Italy towards Istria and Slovenia on Saturday afternoon, reach northwestern Croatia late in the afternoon, and then arrive in Bosnia and Herzegovina and Serbia during the night between Saturday and Sunday, causing rain, showers, thunderstorms, and a significant drop in temperatures, in some places by more than ten degrees compared to Saturday.

It is important to mention that we will only feel the front, not the full cyclonic influence, as it moves further west along the Italian Adriatic coast, meaning the weather change will be quite rapid, confirmed by the stabilization of weather on Monday, and the amount of precipitation will again be quite scarce everywhere. Ahead of the front approaching our regions, as the cyclone enters the Adriatic, it will extend a smaller branch towards us, and from it, a negligible, isolated, weak, and shallow upper-level trough will form over Vojvodina, which will not have a significant impact on us as it will move very quickly eastward towards Eastern Europe with the approaching front.

As we will be facing a change in weather and in the warm sector of the cyclone's influence ahead of the front, very warm air will flow in from the southwest upper-level flow from the western Mediterranean, raising temperatures to a very high 38 degrees. With the passage of the front, the upper-level flow will change from southwesterly to northeasterly, and consequently, cooler air will flow in from northeastern Europe.

Based on the derived synoptic map, the weather in Bosnia and Herzegovina tomorrow will be mostly stable, predominantly sunny, and very hot. In the latter part of the afternoon, characteristic pre-frontal activity will occur in northwestern Bosnia, accompanied by the development of a thin layer of stratiform clouds from which no heavy rain will fall, but it will dissipate quickly. In the rest of the country, it will be sunny, with only weak development of diurnal clouds. During the night, cloudiness from the direction of Kordun will first affect Krajina and northern Bosnia, and during Sunday morning, it will reach the rest of the country, bringing rain, showers, and thunderstorms.

Due to the previously heated ground surface, with the penetration of a significantly cooler air mass into the warm ground in the north and northwest of the country, there is a high probability of vertical cloud development, which could result in more pronounced thunderstorms accompanied by hail, locally heavy precipitation, and gusty winds. The Krajina region is expected to receive the most precipitation (10 to 20 liters), while in the rest of the country on Sunday, it will mostly be between 2 and 10 liters.

Wind intensity tomorrow will be light to moderate, predominantly southwesterly. During the night, with the passage of the front, a strong, and in gusts very strong, northerly and northeasterly wind will temporarily blow in the north and northwest of the country, but it will quickly weaken to moderate.
Morning temperatures will range from 16 to 22 degrees, and in the south from 22 to 27 degrees. The highest daily values will generally be between 32 and 38 degrees.

On Sunday morning, there will be light rain in almost the entire country, while in the latter part of the day, light rain and showers are expected mostly in the central, eastern, and southeastern parts of the country. In Krajina and northern Bosnia, it will generally be dry due to the strengthening atmospheric pressure and the ridge of the Central European anticyclone, leading to a stabilization of weather conditions.

Due to the pressure difference, low in the south and high in the north, a pronounced gradient will be established, making it relatively windy with mostly moderate, and in some places in the north, strong northerly and northeasterly winds, while in Herzegovina, the bora will strengthen. Temperatures will be between 18 and 23 degrees everywhere. Monday will bring stabilization of conditions, but temperatures will rise by 3 to 4 degrees compared to Sunday. Tuesday will again bring predominantly sunny and warm weather, with temperatures rising day by day, so towards the end of the week, according to current forecasts, it will be hot again.