[D66] [JD: 156] Intense heatwave over Europe

Wed Jul 28 08:18:12 CEST 2021

severe-weather.eu
<https://www.severe-weather.eu/europe-weather/most-intense-heatwave-summer-2021-forecast-mk/>

  Parts of southern Europe will be baking with around 40-45 °C as the
  most intense heatwave of summer 2021 is on the way this week

Published: 27/07/2021 By: Author Marko Korosec
<https://www.severe-weather.eu/author/admin/>

Categories Europe Weather
<https://www.severe-weather.eu/category/europe-weather/>

11-13 minutes
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*It looks like the final days of July and early August will bring the
most intense heatwave of summer 2021 in Europe so far. Temperatures are
expected to push well above 40 °C in some areas, potentially up to
around 45 °C is possible over Greece over the weekend. This will
significantly increase wildfire threat across the Mediterranean region
and the Balkan peninsula.*

The month of July has brought some severe heat mostly into the southern
and southeastern parts of the European continent, while any significant
heatwaves have been lacking to the west. The hottest temperatures were
observed over the Mediterranean, the Balkan peninsula, and Turkey,
exceeding 40 °C at times. However, a heatwave was lately also spread
across the normally cooler UK and Ireland, low 30s were reported last week.

But this week, a textbook pattern is establishing over Europe, which is
prone to extremely high temperatures. The remainder of July and also the
early days of August, the final summer season, will bring the most
intense heatwave of 2021.

most intense heatwave summer 2021 forecast balkan peninsula

The reason behind the upcoming strongest heatwave this summer is the new
upper-level blocking of High strengthening from the Mediterranean region
into the Balkan peninsula. The heat will be extreme and should persist
for at least a week, possibly more across the south.

While on the northern side of the expanding ridge, a massive Saharan
dust cloud is being pushed into central Europe
<https://www.severe-weather.eu/europe-weather/dust-cloud-europe-heatwave-mk/>
as well.

Peak temperatures are expected to push well above 40 °C, potentially
even close to around 45 °C in parts of the southern Balkan peninsula, as
well as Italy and other parts of the south-central Mediterranean.

Here is the animation of the temperatures in the lowest parts of the
atmosphere over the next 10 days. A significantly warmer air mass than
normal will quickly increase from the Mediterranean into the Balkan
peninsula, with nearly 10 °C above average temperatures expected.

Parts of Italy, Serbia, North Macedonia, Albania, Romania, Bulgaria, and
Greece are all ready to get baked by the extreme and dry heatwave.
High-resolution model guidance is clear with a good agreement of peak
daytime temperatures approaching the mid-40s during the hottest days.

The air mass during this heatwave will remain rather dry and should also
additionally increase the wildfire potential across southern parts of
Europe where drought is the worst. And destructive wildfires are already
ongoing in Sardinia, Italy
<https://twitter.com/TheInsiderPaper/status/1419827003201663010> this week.

Such a drier-than-normal pattern will likely continue for the South, so
conditions are expected to become even worse. Drought and wildfires are
other side effect of a significant heatwave, while heatstroke remains
the worst.

    SEAS AROUND EUROPE ARE GETTING WARMER

With the quite persistent warmer patterns over the recent weeks, also
the sea surface temperatures have warmer up. Even significantly in some
parts of Europe. Those remain extremely high across the Baltic region,
with the waters being more than 6 °C above normal. Waterspout season
towards this fall could be wild there.

Also very warm are the Atlantic Ocean waters around the UK and Ireland.
About 2 to 4 °C above normal for the end of July which is rather
impressive given the lack of any significant heatwaves over western
Europe so far this summer.

most-intense-heatwave-summer-2021-forecast-sea-temperature

The most concerning part of Europe is, however, the Mediterranean Sea
water temperature. Basically, the whole Mediterranean region has seas
well above the average, thanks to the persistent strong heatwaves and
very high temperatures this year.

Both the sea and lake temperatures are warming up a lot this summer. The
Mediterranean sea has nearly +3 °C above long-term average sea
temperatures in many areas.

Keep in mind that very warm seas are a most important source of high
moisture content that directly reflects into the highest dewpoints and
high to extreme instability when it comes to severe thunderstorms.

Just this Monday, very high moisture contributed to a destructive
hailstorm near Parma, Italy where a striking number of vehicles were
literally destroyed, being trapped in the traffic jams along the highway
Milano – Bologna.

most-intense-heatwave-summer-2021-forecast-hail

/Above: giant hailstones near Parma, Italy. Credits: Meteo Bassano e
Pedemontana del Grappa
<https://www.facebook.com/meteoBassanoPedemontanadelGrappa/> / Tornado
in Italia <https://www.facebook.com/tornadoinitalia>/

When the end of summer approaches in Europe, the seas are typically the
warmest. Resulting in very high dewpoints that often lead to extreme
flooding events across eastern Iberia, southern France, along the
southern Alps, Italy, and the western Balkan peninsula.

Keep this in mind as it could turn to r a potential concerning threat
over the next few months as we enter into progressive fall patterns and
frontal systems.

A rather typical combination of the deep trough/low over the North
Atlantic and western Europe against the blocking High to its east
results in a strong warm advection return from the deep southern parts
of Europe, Mediterranean, and North Africa. Early this week, it also
combines with the massive dust cloud advection from the Saharan desert.

most-intense-heatwave-summer-2021-forecast-pattern

More stable weather is foreseen for a few days across much of Europe.
While in between both large scale features, southwesterly winds will
gradually lead to ample moisture returning toward the Alps. The next
frontal system is likely to arrive at the end of the next weekend.
Severe storms will likely form after a period of hot days.

Under the ridge, the heatwave will rapidly increase in the coming days,
affecting the Mediterranean and the Balkan peninsula, including at least
the southern parts of central Europe. As well as central Italy. While
the temperatures were already in the mid to upper 30s this Monday and
low 40s on Tuesday, they will soon exceed the 40 °C marks. And push much
higher towards the weekend.

The attached chart below is showing the maximum temperatures observed
across the central and southern parts of Europe early this week, on
Monday, July 26th. The Mid to upper 30s were reported from Italy and the
southern Balkan peninsula. Cooler conditions remain across Western Europe.

most-intense-heatwave-summer-2021-forecast-maximum-monday

Extremely hot weather continues over Algeria and Tunisia, reaching
around +50 °C on several days already this month. But it is indeed a dry
heat and a rather normal temperature for the region during peak summer.
The lack of moisture is making it a bit easier to withstand.

    HEAT INTENSIFIES ACROSS ITALY AND THE BALKANS, LOCALLY CLOSE TO 45 °C

This week’s general weather pattern over Europe is a textbook example of
how a strong warm advection brings an intense heatwave. When we see the
low to the west (blueish colors) and high (reddish colors) to the
east-southeast, we should be weather aware that it will lead the
temperature to rise a lot.

A so-called *heat dome* establishes across the southeastern parts of
Europe with an extended period of extreme heat. This is a term that we
use when an area of high-pressure parks over a large portion of the
continent and persists there for days.

most-intense-heatwave-summer-2021-forecast-heat-dome

Heat dome works like a lid on a pot, trapping hot air mass underneath.
And this feature is often blamed to be responsible for long-lasting and
deadly heatwaves around the world. Often a very significant heatwave
develops underneath with temperatures well above normal, challenging
some heat records.

Such a heat dome event brought an unprecedented historic heat over
Pacific Northwest
<https://www.severe-weather.eu/global-weather/heat-dome-record-breaking-heatwave-pacific-northwest-canada-united-states-mk/>
of Canada and the United States a few weeks ago.

During the coming days, temperatures will be gradually rising and likely
reach higher daily highs. Parts of central Europe and the Balkan
peninsula will experience about 10-15 °C warmer temperatures than
normal, an extremely hot period for the end of July.

most-intense-heatwave-summer-2021-forecast-temperature-anomaly

With such an anomaly of the near-surface temperature that are being
forecasted, the peak afternoon maximum values should easily push into
the low 40s. Very likely even higher after tomorrow, Wednesday. The
hottest locations will be the most heat-prone lowlands and valleys.

A scorching heatwave will establish, we can see the highlighted areas
where the lowlands typically bring the highest temperatures on summer
days. The two charts below are showing the highest temperatures on
Wednesday and Thursday, July 27th and 29th, respectively.

most-intense-heatwave-summer-2021-forecast-wednesday-thursday

Parts so southern Italy, Albania, Greece, North Macedonia, Serbia,
Bulgaria, Romania, and western Turkey should be baking in the
temperatures between 39 and 43 °C, according to this weather model.

Towards the weekend, the heatwave likely peaks and brings the highest
temperatures for the same areas. The afternoon will be even hotter,
thankfully also a tad drier, so the Heat Index will remain similar. The
worst combination would be with the high moisture, but this is not
happening this time.

most-intense-heatwave-summer-2021-forecast-friday-saturday

The highest temperatures will be observed over southeast Italy, possibly
also the eastern Po valley on the north, on both Friday and Saturday.
While the strongest heat is expected over the central and southern
Balkan peninsula.

Greece, North Macedonia, Serbia, eastern Croatia, southern Romania, most
of Bulgaria, and also western Turkey should expect 40-44 °C during the
afternoon hours.

To better imagine how anomalous the core of the heat will be to the
south, see the attached GFS Meteogram ensemble forecast charts below.
Those include the 850 mbar (approximately 1500 m ASL) temperature
forecast for Lecce, southern Italy, and Athens, Greece in the southern
Balkan peninsula over the next 14 days.

   The sign of significant warming this week is more than obvious.

most-intense-heatwave-summer-2021-forecast-meteogram

Note, that the temperature over Athens is gradually increasing until the
peak on August 2nd, reaching nearly 27 °C at the 850 mbar level, so
about 10 °C above the normal values at this height. This is undoubtedly
leading to extremely high daytime maximum temperatures, close to mid-40s.

While the right chart for Lecce, Italy hints that the heat will remain
as hot as it is in these days, also peaking around Aug 2nd. Temperatures
are about 7-8 °C warmer than normal at 1500 m ASL.

    EXTREME HEATWAVE EXTENDS INTO EARLY AUGUST, REFRESHMENT TO THE NORTH

Although parts of the Mediterranean and the Balkan peninsula might see
the peak of the ongoing heatwave on Friday into Saturday, the scorching
heat will remain over far southern parts of the peninsula also through
the early days of August.

Sunday could bring nearly 45 °C across Greece, 41-42 °C over Bulgaria,
southern Romania, and western Turkey. With Monday being even hottest,
potentially challenging some heat daily records in the region.

most-intense-heatwave-summer-2021-forecast-sunday-monday

Bulgaria, Greece, and western Turkey could see the peak afternoon
temperatures between 42 and 45 °C on Monday. This will be the hottest
day of the year for the southern Balkan peninsula region.

Refreshing temperatures are expected to arrive into central Europe on
Sunday through Monday as well, staying in the upper 20s to low 30s
during the day. Severe weather will likely develop around the Alps on
Sunday, however.

most-intense-heatwave-summer-2021-forecast-pattern-weekend

But the distance of the potential new frontal system is still too far in
advance and the exact evolution remains uncertain. Stay tuned for
further details in the coming days.

***The images used in this article were provided by Wxcharts
<https://www.wxcharts.com/>, and Wetterzentrale
<https://www.wetterzentrale.de/>.