DISCUSSION: As a very large and intense thunderstorm event erupted across parts of Western and Eastern Europe yesterday afternoon and evening, many of the storms exhibited particularly high amounts of lightning strikes (i.e., a combination of cloud-to-ground, cloud-to-cloud, and intercloud-type strikes). As seen in the graphic below courtesy of lightningmaps.org, there was especially impressive lighting strike density observed across Eastern/Central Spain, Southern France, and several countries just north and east of the Eastern Mediterranean Sea.
As a further explanation, cloud-to-ground lightning occurs as a result of a disproportionate concentration of positive and negatively charged particles in the atmosphere located above and close to or at the ground respectively. This differential in the nature of the electric charge between the cloud-base and the region close to or at the surface results in an electrically-based energy imbalance which in sufficient quantities can result in a discharge in the form of an electric discharge from the cloud and down towards the surface.
Cloud-to-cloud lightning occurs as a result of differentiation in the charges of the particles between nearby clouds associated with intense thunderstorms. As a result of the very intense thunderstorms being close proximity to one another coupled with the strong differential between the positively and negatively charged particles between the respective cloud bases, this can often trigger what we observed as cloud-to-cloud lightning.
Intracloud lightning occurs based on differential in the location of positively and negatively charged particles within an intense thunderstorm (which is often positioned fairly high above the ground and is also referred to as being an elevated thunderstorm). As a consequence of the strong gradient created by the stronger concentrations of positively and negatively charged particles within different parts of the thunderstorm, this electrical in balance with in a thunderstorm cloud often triggers what we observe as intracloud lightning.
To learn more about this and other high-impact weather events from across Europe, be sure to click here!
DISCUSSION: As severe thunderstorms developed across parts of Western Europe during the day yesterday, some of these storms became particularly violent. As seen in the video below captured in part of the Southeastern Netherlands, some storms produced damaging hail on the order of golf-ball to tennis ball-sized hail which caused damage such as that observed on the roof of this home located in the city of Brabant in the Netherlands. The catalyst for such damaging hail stones being produced by these thunderstorms which moved across parts of the Netherlands was a consequence of these thunderstorms moving through regions characterized by enhanced convective instability. As a result of the particularly strong convective instability, thunderstorms which move through these particular unstable regions and ingest this high instability often have very strong upward vertical velocities within the main updraft. The end-result is that these strong upward vertical velocities bolster the potential for hail stones to remain suspended within the icing layers (located in the middle to upper portions of thunderstorm); facilitating longer-duration hail stone growth through the accumulation of ice crystals around the periphery of the initial ice nucleus which serves as the base for hail growth. Having said that, these damaging hail cores induced substantial widespread damage to automobiles, homes, businesses, etc. Note how many glass windows of cars and homes as well as solar panels sustained severe damage as a result of these severe thunderstorms' hail cores moving through these populated regions of the Netherlands. Hopefully, local residents had sufficient time to take necessary precautions ahead of the arrival of these intense thunderstorms! To learn more about other high-impact weather events from across Europe, click here!
DISCUSSION: As strong thunderstorms erupted to the east of the strengthening low-pressure system across parts of Western Europe this afternoon and evening, some of the storms formed in regions of locally high temperature contrast (i.e., due to the combination of strong warm air advection to the east of the low-pressure center and cold air advection to the west of the low-pressure center). As strong thunderstorms formed in the warm front sector near part of this strengthening temperature gradient, very impressive shelf clouds formed in association with these thunderstorms. Shelf clouds form as a result of quickly moving warm air being lifted up and over cooler air advancing ahead of the leading edge of a strong to severe thunderstorm. This process leads to the rapid condensation of low-to-mid level moisture; favoring the formation of cloud phenomena including but not limited to shelf clouds! Attached below is an absolutely classic example of this process occurring over western portions of the Netherlands earlier today. To learn more about other high-impact weather events across Europe, be sure to click here!
DISCUSSION: As strong thunderstorms erupted earlier yesterday afternoon across parts of Northwestern to North-Central Europe, some of the storms formed in regions characterized by relatively high convective instability which helped to produce thunderstorms with very strong updrafts. Along with the presence of very strong vertical updraft velocities, these storms also quickly developed very robust downdrafts. Some storms such as this one observed over in Warsaw, Poland yesterday afternoon produced an atmospheric phenomena which is scientifically referred to as a downburst. Downbursts typically occur as a consequence of downdrafts associated with intense thunderstorm being enhanced by rain-cooled air which effectively speeds up the rate at which air descends in the region of the thunderstorm's downdraft due to the increased density of the rain-cooled air as compared to the more buoyant surrounding environment. As a consequence of this denser rain-cooled air descending through the lower/middle parts of the thunderstorm, it races towards the surface quite violently which facilitates strong episodic bursts of strong winds such as that observed in the footage below as captured by Szymon Świeży. To learn more about other high-impact weather events from across Europe, be sure to click here!
GREAT VIEW OF A FUNNEL CLOUD EARLIER IN WELLINGTON, UNITED KINGDOM! (credit: Wellington Primary School PTA via WeatherNation)
DISCUSSION: As a weak low-pressure continued to slowly move across parts of the British Isles earlier today, a round of strong to severe thunderstorms ripped through parts of Western Europe. As some of these storms moved across parts of Western Europe and consequently encountered stronger vertical wind shear, certain storms developed pronounced rotating updrafts such as the storm captured in the image below earlier today in Wellington, UK. Note how in this particular storm there was an incredibly low cloud base; indicative of a surface-based convective storm and also how there was clear evidence of a developing funnel cloud as well! Though it did not last very long beneath the lowered cloud base near the center of the base of this thunderstorm (more scientifically referred to as a wall cloud), this indicates the presence of both sufficiently strong instability and vertical wind shear based on the occurrence of this funnel cloud for even a brief time! To learn more about other high-impact weather from across Europe, be sure to click here!
DISCUSSION: As a commercial flight made its final approach towards Istanbul Atatürk International Airport, there were some strong thunderstorms which were moving towards and through the areas in and around Istanbul, Turkey. As a result, the pilot and the entire cabin crew and passenger population aboard this flight saw quite an impressive lightning show as seen in the image below courtesy of Turkish Airlines Pilot Utku Utkan. Note how close the lightning was in the photograph captured below by the aforementioned pilot. Typically, all over the world, pilots and especially commercial airplane pilots will often do their very best to avoid flying near or through strong to severe thunderstorms due to the inherent dangers posed by strong updrafts and/or downdrafts in the vicinity of the core of the thunderstorm. Nonetheless, here was a case where the pilots (based upon their likely required flight path by the local Air Traffic Controller) had no choice but to fly in close proximity to this particular area of thunderstorm activity. Absolutely breath-taking shots to say the least! To learn more about other high-impact weather from across Europe, click here!
DISCUSSION: As intense thunderstorms developed over the Northern Ligurian Sea earlier today, heavy rainfall began to move inland as the associated convective storms moved eastward and headed inland over Northwestern Italy. As a result of very persistent thunderstorm activity pumping in off of the Northern Ligurian Sea, there was a large threat for widespread flooding and flash flooding. Ultimately, the threat for highly-impactful flooding was verified as a result of heavy, persistent rainfall moving through the region this afternoon and evening (local time). Note how many of the roadways in the photographs included below clearly indicate the results of massive flooding across this part of Northwestern Italy! To learn more about other high-impact weather from across Europe, be sure to click here!
DISCUSSION: Despite it feeling like the beginnings of Summer across much of North America over the last week or so coupled with more very warm weather on the way for much of North America during the week ahead, it has been quite a different story across some parts of Western Europe. As shown in the image below, there was even a considerable amount of accumulating snowfall across parts of Northern Finland! This accumulating snowfall came as a result of a strengthening low-pressure system which emerged off of the North Atlantic Ocean and brought a plethora of moisture-laden air towards much of Western and Northwestern Europe! Here is some very impressive late-Spring snowfall in the heart of Western Europe! Just more evidence that as noted in the post below (courtesy of Meteo Europe), Nature does not follow the seasonal clock at all times! To learn more about other high-impact weather from across Europe, be sure to click here!
GORGEOUS TORNADO OBSERVED NEAR HAMBURG -BRAMFELD, GERMANY A FEW HOURS AGO! (credit: Benjamin Kempkes via Meteo Europe)
DISCUSSION: As severe thunderstorm erupted across parts of Western Europe earlier today, some of these more discrete convective storms (i.e., storms which were more isolated with respect to the majority of the convective storms moving through the region) moved into an environment defined by stronger vertical wind shear (i.e., changes in the strength and/or direction of the winds with height) and particularly high convective instability. As a result of these changing environmental conditions, storms such as this one developed strong, rotating updrafts capable of producing tornadoes as happened with the storm captured below courtesy of Benjamin Kempkes. Note how the condensation funnel is so crystal-clear in this particular storm with a weak presence of rainshafts dancing around the funnel a bit! A very photogenic tornadic storm to say the least! To learn more about other high-impact weather from across Europe, be sure to click here!
DISCUSSION: As discrete convective storms fired up across parts of Western Europe earlier today, some of these storms grew fairly high into the middle and upper portions of the atmosphere. One great example was this particular thunderstorm which erupted over North Rhine-Westphalia, Germany (located in Western Germany). Note how you can identify the height at which the upper-level inhibited any further vertical propagation of the main updraft based on the spread of the upper-level cumulonimbus cloud debris outward from the center in the form of an anvil! Just about as classic as it gets (and lucky too) to see a mature thunderstorm from a commercial aircraft! To learn more about other high-impact weather from across Europe, be sure to click here!