Belgium under nationwide yellow thunderstorm warning from Thursday afternoon
Belgium’s Royal Meteorological Institute has placed the entire country under a yellow thunderstorm warning from 17:00 on Thursday, 27 August, until 04:00 on Friday, with intense rain, hail and strong wind gusts forecast locally.
The warning covers the full country during the evening travel and activity period. Short bursts of intense rain, hail, lightning and strong gusts can disrupt roads, rail services and outdoor events and can cause highly localised flooding or damage.
Updated 27 August 2026 — : The () has placed every Belgian province and under a yellow thunderstorm warning from 17:00 on Thursday until 04:00 on Friday. The institute expects a storm system to enter Belgium from the south late in the afternoon, bringing locally severe thunderstorms and a risk of disruption.
The forecasts rainfall totals of 20 to 40 litres per square metre within one to six hours in several places, with higher amounts possible in isolated locations. It says the storms can also produce hail and strong wind gusts. The precise path and intensity of individual cells remain uncertain because thunderstorms develop on a small geographical scale.
A yellow warning means vigilance is required. Under the ’s official system, that level is issued when hazardous weather has a sufficient probability of reaching defined thresholds within 48 hours. For thunderstorms, the yellow criteria include heavy rainfall, hailstones measuring one to two centimetres, strong gusts or dangerous lightning. The warning does not mean that every municipality will experience severe weather.
The alert follows an exceptionally warm and dry Belgian summer. In a seasonal assessment published this week, the said summer 2026 was on course to become ’s warmest since national records began in 1833. It also reported an unusually dry period between 1 July and 15 August. That background does not determine where Thursday’s storms will strike, but intense rain falling rapidly onto hard or dry ground can create local drainage and surface-water problems.
The weather system forms part of a wider unstable pattern affecting France and neighbouring areas. reported successive storm outbreaks this week and expected an active storm zone to extend towards northern France on Thursday, consistent with the ’s forecast of storms entering from the south.
Residents should secure loose outdoor objects, avoid sheltering beneath trees and monitor the ’s warning map and radar. The National Crisis Centre advises people to follow official information during natural hazards. Travellers and event organisers should allow for sudden local disruption, while the IRM may revise the warning as observations clarify the storms’ route and strength.
Impact
Regional — The warning applies to Flanders, Wallonia and Brussels. The storms are forecast to enter from the south, but the IRM has not identified any one Belgian region as certain to receive the strongest impacts.
Local — Brussels is included in the nationwide warning during the Thursday evening travel and activity period. Residents, commuters and event organisers should be prepared for highly localised heavy rain, hail, lightning or strong gusts between 17:00 and 04:00, even if nearby areas remain largely unaffected. Short downpours may disrupt roads, public transport and outdoor plans or produce localised flooding. The forecast does not indicate that Brussels will necessarily experience worse conditions than Flanders or Wallonia.
What it means for you
If you are travelling, commuting or attending an outdoor event on Thursday evening, check the latest IRM warning and transport or organiser updates before leaving. Carry rain protection, allow extra journey time and avoid exposed outdoor locations during lightning or strong gusts. Secure loose items on balconies, terraces and gardens, and move vehicles or valuables away from places prone to local flooding where practical. The main period to watch is 17:00 on Thursday, 27 August, through 04:00 on Friday; conditions may vary sharply over short distances.
Who, where and what
Key people, places and terms in this story
The entire country is covered by the yellow thunderstorm warning.
The capital region is included in the warning alongside every Belgian province.
Belgium’s northern region is covered by the warning.
Belgium’s southern region, from which the storms are forecast to enter, is covered by the warning.
The recent season assessed by the IRM in relation to heat and drought.
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The entire country is covered by the yellow thunderstorm warning.
The capital region is included in the warning alongside every Belgian province.
Belgium’s northern region is covered by the warning.
Belgium’s southern region, from which the storms are forecast to enter, is covered by the warning.
The recent season assessed by the IRM in relation to heat and drought.
Belgium’s federal weather service and the issuer of the nationwide warning.
The French abbreviation used for the Royal Meteorological Institute of Belgium.
Belgian news outlet reporting the nationwide warning.
French national weather service cited regarding successive storm outbreaks in France.
Federal authority providing public information on natural hazards in Belgium.
Sources & evidence
- View sourceRoyal Meteorological Institute of Belgium — national warningsPrimaryofficial· meteo.be· 27 August 2026Retrieved 26 August 2026· 36 days ago· Dated
- View sourceLa Libre Belgiqueprimary· lalibre.be· 26 August 2026Retrieved 26 August 2026· 37 days ago· Dated
- View sourceRoyal Meteorological Institute — warning system explanationofficial· meteo.beRetrieved 26 August 2026
- View sourceMétéo-France — successive storm outbreakscorroborating· meteofrance.com· 26 August 2026Retrieved 26 August 2026· 37 days ago· Dated
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This briefing was prepared with AI assistance and reviewed by a Belgium Impulse editor before publication. methodology.