The much hotter-than-normal summer season of 2024 has just ended, but weather across Europe remains sweltering hot. Thanks to an extensive heat dome dominating much of the continent as September starts, the heatwave is nowhere near its end. The first day of September has already set numerous new temperature records, and the upcoming days will further challenge the all-time high temperatures for the first month of the autumn season.
According to the forecasts of the global weather models, many countries across the south will continue to experience daytime temperatures above 35 °C. Temperatures throughout early September will remain much above average across the European continent.
Central Europe, Italy, and the Balkan peninsula are expected to experience the most anomalous hot temperatures. The unseasonably strong heat is forecast to remain for at least another week.
August 2024 ended with significant warmth and heatwaves in the southern half of Europe and across parts of France, central Europe, and the Balkan peninsula. After July, the last month of the summer season 2024 also ended as a record-breaking month.
Temperatures are repeatedly pushing into the mid to upper-30s locally, and this will also continue over the first few days of September.
The general weather model consensus suggests that the first 10 days of the month will be significantly warmer than normal for much of Europe.
September starts with new monthly records across central Europe
Over the last few days, daily records were shattered across southern and central Europe due to the ongoing heatwave. Late August usually starts a summer cooling down, but not in 2024. Temperatures remain extremely high as we enter the first autumn month.
Today, Sunday, September 1st, was already an astonishing record-breaking day. Hundreds of weather stations across central Europe have obliterated their all-time high September records. Tens of station records were set in Germany, Czechia, Poland, Austria, Slovenia, Croatia and Hungary.
Some countries, e.g., Slovenia, have seen their first ever 35 °C surpassed in September. Multiple stations breached this statistical threshold today.
An extremely hot September day was also recorded across Benelux and western Germany, with temperatures around 28 °C also recorded in southern England. Most of the Balkan peninsula peaked around the mid-30s, and central Italy reached around 38 °C.
These temperatures are extremely hot and historic for early September!
This weather pattern will continue to dominate over the first week of September and establish a large Omega-blocking pattern across the continent. Thus, scorching hot weather is maintained throughout most of the week across the south, west, and central Europe. Let us repeat once again; it is already September!
The general weather picture indicates that a blocking high – the upper ridge – will strengthen from the southern Mediterranean region into central and northern Europe, thanks to a heat dome dominating the European continent aloft.
What is a Heat dome, and why does it bring long-lasting heatwaves and excessive temperatures?
The Heat Dome is generally the primary background feature that causes yearly intense heat waves. During the summer of 2023, there were extreme heatwave events, which continued into September and October. A similar trend was also in the summer of 2024. There have been thousands of record-breaking stations, and the temperature anomalies have often been off the charts.
Similar events occurred across the Balkan peninsula and Eastern Europe through mid-late July and late August this year.
While heat waves broke records again this summer, their longevity and nighttime lows are especially astonishing. Also, on the global scale, July 21st set the new world record for the daily global surface air temperature. It was 17.09 °C, breaking the old record by 0.01 °C on July 6th, 2023.
Global temperatures from January through August this year have exceeded the long-term averages. This anomaly has been so significant over the last 12+ months that the chart provided by CopernicusEU undoubtedly speaks for itself. In August, temperatures are already decreasing statistically, but the current daily global temperatures generally remained much above the average.
The Heat Dome is that feature that leads to these extreme heat events. Usually, the heat dome is the main and the most dominant feature of summer weather patterns in Europe and North America. Still, it can also occur in autumn, as we are experiencing last year.
We hear the term heat dome when extremely high and anomalous temperatures develop. Here is how it works and why it is essential to understand it from a larger scale. The upper-level ridge pattern, or warm air mass in the higher altitudes, is known as the Upper High (we often use the term blocking High). It usually forms the heat dome.
So, this specific term is used when a broad area of high-pressure parks over a large portion of the continent. If the event is exceptionally stable and extreme, it usually stays there for several days or weeks.
The heat dome works like a lid on a pot. The extensive dome of heat traps a significantly warmer air mass at all levels underneath, sinking its layers toward the ground. Therefore, the air mass becomes dry and significantly warms as it reaches the lowest elevations.
A heat wave associated with a heat dome creates fair, stable weather and an often arid air mass with minimal chances for precipitation or even clouds. This happens due to the sinking air parcels in the center of the heat dome, resulting in rising temperatures. Sometimes, we see the weather pattern developing a so-called Omega blocking High.
The example below shows this kind of omega-blocking pattern over Europe from early September last year. The pattern engulfed a large part of the continent, with a central heat dome and a low-pressure system on each side. One low was over the southern Mediterranean, and the other over the Azores.
Especially during dry summer, drier and warmer weather produces a significantly enhanced wildfire threat due to developing drought. Or additionally worsening the ongoing, pre-existing, arid conditions. Such examples were wildfires in the Pacific Northwest and other parts of western North America in recent years or in Europe (Greece, Portugal, etc.) during last year’s summer season.
A heat dome is often also to blame for deadly heatwaves worldwide, as the scorching and excessive heat usually lasts for a very long period. Such heat dome events brought record temperatures in many countries worldwide in the summer of 2023 and 2024, extending into the fall seasons.
The daily average, minimum, and maximum temperatures under the heat dome are typically significantly above average. When the heat dome is solid, it challenges existing historical records. This becomes particularly striking when this feature develops during early summer or autumn.
An Omega blocking pattern establishes a heat dome and maintains the heatwave underneath
The unusually hot weather will continue through early September, thanks to a persistent heat dome and a strengthening Omega blocking high across Europe.
The warm plume above will allow the heatwave to maintain its path from the central Mediterranean towards France, Italy, and central Europe, then expand further north towards the UK, Benelux, Germany, and northern Europe late this week.
The upper-level ridge is forecast to be the strongest early into the mid-week, pushing temperatures in the lowest levels into the upper-30s across Italy and the central Balkans and the low-30s in France, Germany, and eastern Europe.
The highest temperature anomaly is expected across the Mediterranean, France, Germany, Benelux, the UK, most of central Europe, and Scandinavia from Wednesday through Saturday. Temperatures will be around 8-12 °C above the average for early September.
The strengthening heatwave will allow temperatures to climb the most in Germany, Benelux, Italy, Croatia, Hungary, Bosnia, Serbia, Czechia, and Slovakia.
The following chart indicates a 2 m temperature anomaly on Saturday next weekend, with abundant heat underneath the heat dome and a strong Omega blocking the upper ridge aloft.
Heat will be the most intense across southern and central Europe.
While the heatwave will be strongest across southern Europe and especially the Balkans during the first days of next week, it will also spread further north after Wednesday. Due to an upper low from the Atlantic, the hottest air mass will gradually diminish across southwestern Europe. Still, the rest of the continent will continue to experience hot summer-like weather.
Therefore, scorching heat will continue throughout Southern and Central Europe through early September.
The general temperature picture hints at the summer heat continuing to dominate the southern half of Europe through the start of September. Below is a video animation of the heatwave’s maintaining across Europe and its progress across the continent next week.
After next weekend, the overall weather model consensus also suggests that some chances for rain and thunderstorms could return, collapse the blocking High, and finally start a more seasonable weather trend.
However, the South and East remain more stable, hot, and dry, and the extreme wildfire threat continues or worsens.
Peak temperatures will be in the upper 30s in Italy and the Balkans. France, Benelux, Germany, and the UK will be near the 30s next weekend
With the upper High gradually expanding north from the Mediterranean towards Northern Europe this week, temperatures will remain much above average for many countries.
Temperatures will be the highest across Italy, the Balkan peninsula, and central Europe.
France, Benelux, Germany, Czechia and Poland
North of the Alps, temperatures will have a temporal pause after the weekend heat but will gradually increase after mid-week again. Therefore, from Wednesday through Saturday, peak afternoon temperatures are forecast to reach the mid to mid-30s across eastern Germany, Czechia, and Poland.
Most of France will remain in the mid- to upper 20s, excluding the southern parts, where peak temperatures will continue in the low 30s. After Friday, temperatures will warm up again across France and Benelux, nearing the 30s over the weekend.
It will usually be warm for September further north across Denmark and southern Sweden, thanks to the center of the Omega blocking high aloft. Peak temperatures will also push close to the 30 °C from Friday to Sunday.
the UK and Ireland
Sunday was very warm across the UK, while through mid-week, temperatures will be going down across the UK and Ireland due to the effect of a shallow low moving across the region from the Atlantic. However, warmer temperatures will again spread throughout the UK towards the weekend.
Daytime temperatures will reach mid-20s across England and Scotland from Friday through Sunday this week. Low 20s are forecast for Ireland as well.
Temperatures are likely to decrease gradually after the next Monday.
Spain and Portugal
Excessive heat, with temperatures in the mid-30s to locally upper 30s, will remain over the southern and central portion of the Iberian peninsula this week.
Multiple consecutive days will bring temperatures into the 34-37 °C range across southern and central Spain and Portugal.
The northern part of the peninsula will experience cooler maritime airmass from the Bay of Biscay, so hot weather is not expected there.
Temperatures across the south will likely remain hot also over the next weekend.
Italy and the Balkans
According to some global mid-range weather models, the heatwave across the Mediterranean and Balkan peninsula is expected to continue through early September and could extend into mid-month.
The forecast peak temperatures from Monday through Thursday suggest that parts of Italy, the south-central Balkans, and the Panonian plains will experience mid to upper 30s for multiple days.
After this Sunday’s record-breaking values of September, these temperatures are ready to challenge more daily temperature records for the region.
According to long-range weather models, some temperature changes are foreseen across some parts of Europe later this month. Higher moisture could bring some much-needed rain and temperatures back into near-normal values after this heatwave is finally over.
The Health Risks During A Heatwave
During an extended period of hot weather, generally surpassing +35 °C, it is physically challenging and presents an enhanced risk for health.
Sweltering weather, particularly in extended periods – heat waves – is uncomfortable but presents a significant health risk.
Who is most at risk?
Scorching hot weather is uncomfortable for most people. The following groups are particularly threatened by the very high temperatures we encounter during heat waves:
- elderly people aged over 75 years
- babies, young children
- people with chronic/long-term health conditions, such as diabetes, respiratory disease, circulatory disease
- People who are obese
- People taking certain medicines
- people who work outdoors, in hot/poorly ventilated areas, or engage in physical activity in hot weather
- socially isolated people
- people who are not acclimatized to hot weather, such as tourists from northern countries
Always stay cool, hydrated, and healthy in scorching hot weather
Staying hydrated is one of the most crucial things during extreme heat. Consider taking these precautions and measures to stay healthy in scorching weather:
- Drink plenty of water! – A human’s body cools through sweating; on a sweltering day, an adult may lose up to several liters of water. Keep drinking water, and avoid drinking alcohol, hot drinks, and drinks with high sugar content, as they can worsen dehydration. Regular water intake is a good way of preventing dehydration.
- Keep your body cool; stay out of the sun if possible. Eat small meals, preferably fruit and salads. Wear light-colored and loose clothing made from natural materials like cotton. Take a cool shower or a cold bath if you feel hot. Also – keep your workspace and living space cool. If you do not have air conditioning, shut the curtains and blinds during the day. Stay in the coolest room, and avoid using the stove and oven as much as possible. If your home gets too hot, go to a cooler place – a library, shopping center, cinema, or swimming pool.
- Keep your food safe! Properly Store food that needs refrigeration! Food spoils rapidly at high temperatures, and you may risk food poisoning if it is not stored correctly.
- If you need to go out in the sun, protect your skin, use proper sunscreen and clothing to avoid sunburns, and cover your head correctly.
- Know your body and have a plan – Ask your doctor if you have any health conditions that may increase the risk of heat-related illness. Call and consult with your doctor if you are feeling unwell. Call emergency help (know the number!) if you feel unwell!
Common heat-related illnesses with symptoms: What to do if it happens?
WHO considers these symptoms’ descriptions and treatments below as informative only – consult with your doctor for details and professional advice:
Dehydration
Dehydration occurs when the body loses too much water to maintain normal functions. Symptoms include dizziness, tiredness, irritability, thirst, dark yellow urine, loss of appetite, and fainting. Drink plenty of water or diluted fruit juice. Avoid coffee, alcohol, and sugary drinks. Move to a cooler space to cool off. If you feel unwell, call your doctor or emergency room.
Heat rash
Heat rash is an itchy rash caused by excessive sweating. Move to a cooler, dryer environment, and keep the affected areas dry. Hydrating creams may make the condition worse. Consult with your doctor.
Heat cramps
This happens during strenuous activity when the body sweats and loses water and salt. Heat cramps manifest as muscle pains or spasms. If this happens, stop all activity, move/lie down in a cool place, and raise your legs slightly. Drink water or diluted juice. Have a cool shower or bath, and apply ice packs. Refrain from returning to strenuous activity for several hours. If heat cramps do not subside, seek medical help.
Heat exhaustion
Heat exhaustion is a condition caused by dehydration, which causes excessive loss of water and salt. Symptoms include heavy sweating, pale skin, fast and weak pulse, fast and shallow breathing, muscle weakness or cramps, tiredness and weakness, dizziness, headache, nausea or vomiting, and fainting.
If heat exhaustion occurs, the body needs to be cooled and rehydrated by moving to a chilled place, lying down, having a cool shower or bath, and placing cool packs under the armpits, groin, or back of the neck. Rehydration should be done by taking small amounts of cool fluids. Medical help is advised if symptoms do not abate within an hour.
Heat stroke
Heat stroke happens when the body temperature reaches 40.5 °C, a severe and life-threatening condition! Immediate first aid in lowering body temperature is critical, and an immediate call for an ambulance! Find more information on heatstroke here.
High relative humidity during a heatwave can also significantly affect the body, making it physically challenging for those working outside. After high rainfall, intense heating helps evaporate the soaked grounds, resulting in higher humidity than usual.
We use a heat index to represent the natural feel of scorching hot temperatures and high humidity. These graphics indicate the natural feel of temperatures based on the temperature and humidity.
As we see, when air mass has a temperature around +35 °C, humidity below 60 percent is much less challenging than once the humidity is very high, e.g., above 80 %. Thus, the actual feel temperature would be near 50 degrees Celsius.
Even at temperatures close to the 40s, such sweltering hot air becomes hard to handle with even lower humidity, 50 to 60 percent.
Wxcharts, Pivotalweather, and Wetterzentrale provided images for this article.
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