Sladić: Bosnia and Herzegovina will be hit by the heatwave Polifemo, temperatures heading towards 40 degrees by the end of the week

Written by Nedim Sladić

Summers that bring more than four heatwaves to Bosnia and Herzegovina during the entire climatological summer (June 1 - August 31) are extremely rare. And this year we have many.

We are facing the sixth heatwave, which Italian meteorological services have named Polifemo after Hannibal and Lucifer. It will manifest with moderately strong intensity, but with less duration compared to the previous one. However, according to initial forecasts, it will not be shorter than seven days.

The situation that would bring cooling after September 2 is still very questionable, as we are moving out of the seven-day reference period within which accurate weather forecasts can be made.

Although single-digit air temperatures were measured on Monday and Tuesday mornings, for example, only 8 degrees in Butmir, and even 1 degree in neighboring Serbia, specifically in Sjenica, these values will significantly increase in the coming days. An Iberian minimum within a cyclone will form over Spain and deepen almost to Gibraltar, which will cause a push of air mass from North Africa, as part of a formed thermobaric ridge and a strong anticyclone in the Mediterranean, to transport very hot air towards our regions in a pronounced high-altitude southwesterly flow. This will continue until the first days of September, when, according to the current situation, the peak of the heat would follow.

As both the surface and upper layers will be characterized by uniform pressure, there will be almost no wind, and a strong anticyclonic field will neutralize potential instabilities over the Balkans, ensuring clear skies over most of the Balkans.

According to available forecast material based on the GFS and ECMWF prognostic models, with a comparison made with three others: UKMO, ICON-DWD, and ARPEGE, in the period from August 24 to September 2, sunny and hot weather will prevail, and from the weekend, very hot weather, with temperatures rising higher and higher each day.

In terms of altitude, temperatures will start rising from tomorrow, and in many parts of Bosnia and Herzegovina over the weekend and early next week, they will even exceed 35 degrees.

Temperature ranges will be mostly from 29 to 34 in Bosnia tomorrow, and from 31 to 36 in Herzegovina, and over the weekend, everywhere from 33 to 39 degrees.

Minimum temperatures will still be low tonight, but from Saturday onwards, they will be slightly above 15 degrees everywhere, so the values will again be appropriate for August, and we won't need jackets.

Although it is the end of August, the chance of tropical nights in northern Bosnia (minimum temperature not falling below 20 degrees throughout the night) should not be ruled out, although the probabilities for such an event are decreasing, mainly because the nights are getting longer, thus extending the cooling process.

The peak of the heat should be expected around August 31 and September 1, when temperatures in northern Bosnia and southern Herzegovina will again reach 40 degrees.

An anomaly in air temperature deviation is also evident from August 28 to September 2, which is 8 to 12 degrees higher than the long-term average (1981-2010), according to both prognostic models. As we move beyond the seven-day period, numerical analysis begins to diverge, and the situation after September 1 becomes more complicated.

While the ECMWF prognostic model extends the heat until September 3, the GFS model predicts the passage of a weakened front north of us on the night of September 1-2, bringing a more pronounced drop in temperatures.

In this case, the main role will be played by the strength of the anticyclone itself and how the front will react when it recognizes its strength and approaches our regions, as the GFS currently suggests.

Accordingly, we will know what awaits us after September 1 only after the weekend. Summer does not give up that easily.

There will be no precipitation in many places in Bosnia and Herzegovina for at least another eight days.