There will initially be plenty of sunshine over the southeast on Saturday, but more variable cloudiness will come with a possibility of low cloud, some haze or a fog bank in Flanders. In the followingnoon, sunny spells will alternate with cloudy periods, according to forecasts from the Royal Meteorological Institute (IRM). The weather will remain dry in most regions, with only the risk of a local downpour, mainly in the north-east of the country as well as in the Ardennes.
The maxima will be between 20°C in the Hautes Fagnes and 24 or 25°C locally. In the morning, the wind will be weak from the southwest inland. During the day, it will become moderate and turn north-northwest. On the Coast, it will sometimes be quite strong in the followingnoon, with peaks of up to 50 km/h. This evening, the weather will remain dry with large clearings and high sails. During the night, low clouds will form in places in the Ardennes. The minima will be between 7 and 10°C in Upper Belgium and between 11 and 14°C elsewhere. The northerly wind, moderate at first and temporarily still quite strong on the coast, will gradually weaken.
Sunday will begin under widespread sunny spells. During the day, residual humidity, linked to the remnants of a warm front over the North Sea, will however give rise to cloudy periods. The weather will remain dry in most regions, but thicker clouds might release a few drops on the Hautes Fagnes relief. The coastal region will benefit from sunnier conditions. The maximum will be between 16 and 19°C in the Ardennes, around 20 or 21°C by the sea, between 22 and 24°C elsewhere, and around 25°C in Belgian Lorraine. The wind will generally be moderate from the north.
Monday, the anticyclone will shift towards the Netherlands and will cause sunnier weather. However, cloudy fields might still temporarily drift over the northeast of the territory. Temperatures will begin to rise with maximums of 20 to 23 degrees in the Ardennes, around 23 degrees on the coast, and 24 to 27 degrees elsewhere, under a weak to moderate north to northeast wind.
Mardi, the high pressure area will progress towards Central Europe and direct warmer continental air towards our regions. The weather will remain dry and sunny with occasional high sails. The maximum will be around 25 or 26 degrees in the Ardennes, and between 27 and 30 degrees elsewhere. The wind will be weak from south-southeast to south-southwest, with the possibility of a light sea breeze on the coast in the followingnoon.
Wednesday, temperatures might still reach values around 30 degrees (or even locally a little more) in the center, but a new anticyclone approaching from the west might already induce an intrusion of cooler Atlantic air towards our regions, with d advantage of cloudy fields. The timing of this transition is still uncertain.
Thursday and Friday, the anticyclonic zone over the Near Atlantic will extend towards our regions; it should maintain stable and temporarily less warm air there, with highs around or slightly above 25 degrees in the center of the country. The weather will often be sunny with sometimes transient cloudier passages.