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Cyclone Lothar
Cyclone Lothar is regarded as the worst European windstorm recorded during the 20th century. Crossing France, Belgium, Luxembourg and Germany between 25 December and 27 December 1999, Cyclone Lothar's average winds reached up to 115 km/h inland (Orly), but with gusts exceeding 150 km/h, almost equivalent to a Category 2 hurricane, resulting in 110 deaths (including 88 in France alone) and more than €15 billion in damage, becoming the costliest European windstorm ever recorded.
Lothar moved at 100 km/h along an axis from Brittany (about 4 am) to Lorraine (about 9 am) to Alsace (11 am) with a front 150 km wide. It was the second of a series of devastating European windstorms which made landfall in December 1999, occurring around three weeks after Cyclone Anatol, which caused severe damage in Denmark and nearby parts of Sweden and Germany. The day after Lothar moved over western Europe, another intense European windstorm, Cyclone Martin, caused severe damage to the south of Lothar's track.
A series of severe winter storms crossed the North Atlantic and Western Europe in December 1999. In early December, Denmark was hit by Cyclone Anatol which caused severe damage there and in neighboring areas. A second storm then crossed Europe on 12 December. Starting on December 20, 1999, the Iceland depression strengthened and created a strong temperature contrast along a polar front across the Atlantic. Meanwhile, a high-pressure system covered Central and Eastern Europe. A very deep and sizable depression moved across Britain on the night of 24–25 December (analysed to have possibly reached a low of 938 mb between Scotland and Norway), this set up a large area of westerly flow into Europe which brought Lothar. This highly unstable situation inevitably meant low predictability, and saw an unusually straight and strong jet stream (similar circumstances were also noted the day before the arrival of the Great Storm of 1987).
Lothar moved rapidly, pushed by a strong jet stream on the morning of December 26, at a speed close to 130 km/h. It reached a central pressure of 985 hPa about 300 km south of Ireland. As it approached the northwest coast of France, the storm slowed to 97 km/h before beginning a rapid intensification phase. The central pressure dropped by 32 hPa in 8 hours, falling to 960 hPa during the storm's passage over Paris, which corresponds to the definition of a meteorological bomb. Its deepening intensified on land due to strong interaction with the high-altitude jet stream, which was close to 400 km/h at 9,000 m altitude.
Lothar was extremely intense and only 300 km in diameter, much smaller than the typical diameter for a mid-latitude depression. Its rapid intensification generated an internal pressure gradient comparable to what is observed in Category 2 hurricanes. Exceptionally strong winds were recorded in an area 150 km south of the depression's center.
Before Lothar dissipated, a new disturbance formed near where Lothar had formed. This storm, called Martin, followed a path 200 km south of Lothar and reached its recorded minimum pressure of 964 hPa. Its winds were at maximum intensity as it approached the French coast on the evening of December 27, comparable to those of Lothar: 190 km/h on the coasts and 158 km/h inland.
Storm Martin then struck France and central Europe from 26 to 28 December 1999. At the end of January 2000 two additional damaging storms crossed Denmark and the northern part of Germany.
After the problems of the great storm of 1987, European meteorological services greatly improved their numerical weather prediction models, and Météo-France predicted Lothar. However, cyclone Lothar was not well predicted, with one meteorologist later claiming that forecasts could be split into those that were poor and those that were very poor.
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Cyclone Lothar
Cyclone Lothar is regarded as the worst European windstorm recorded during the 20th century. Crossing France, Belgium, Luxembourg and Germany between 25 December and 27 December 1999, Cyclone Lothar's average winds reached up to 115 km/h inland (Orly), but with gusts exceeding 150 km/h, almost equivalent to a Category 2 hurricane, resulting in 110 deaths (including 88 in France alone) and more than €15 billion in damage, becoming the costliest European windstorm ever recorded.
Lothar moved at 100 km/h along an axis from Brittany (about 4 am) to Lorraine (about 9 am) to Alsace (11 am) with a front 150 km wide. It was the second of a series of devastating European windstorms which made landfall in December 1999, occurring around three weeks after Cyclone Anatol, which caused severe damage in Denmark and nearby parts of Sweden and Germany. The day after Lothar moved over western Europe, another intense European windstorm, Cyclone Martin, caused severe damage to the south of Lothar's track.
A series of severe winter storms crossed the North Atlantic and Western Europe in December 1999. In early December, Denmark was hit by Cyclone Anatol which caused severe damage there and in neighboring areas. A second storm then crossed Europe on 12 December. Starting on December 20, 1999, the Iceland depression strengthened and created a strong temperature contrast along a polar front across the Atlantic. Meanwhile, a high-pressure system covered Central and Eastern Europe. A very deep and sizable depression moved across Britain on the night of 24–25 December (analysed to have possibly reached a low of 938 mb between Scotland and Norway), this set up a large area of westerly flow into Europe which brought Lothar. This highly unstable situation inevitably meant low predictability, and saw an unusually straight and strong jet stream (similar circumstances were also noted the day before the arrival of the Great Storm of 1987).
Lothar moved rapidly, pushed by a strong jet stream on the morning of December 26, at a speed close to 130 km/h. It reached a central pressure of 985 hPa about 300 km south of Ireland. As it approached the northwest coast of France, the storm slowed to 97 km/h before beginning a rapid intensification phase. The central pressure dropped by 32 hPa in 8 hours, falling to 960 hPa during the storm's passage over Paris, which corresponds to the definition of a meteorological bomb. Its deepening intensified on land due to strong interaction with the high-altitude jet stream, which was close to 400 km/h at 9,000 m altitude.
Lothar was extremely intense and only 300 km in diameter, much smaller than the typical diameter for a mid-latitude depression. Its rapid intensification generated an internal pressure gradient comparable to what is observed in Category 2 hurricanes. Exceptionally strong winds were recorded in an area 150 km south of the depression's center.
Before Lothar dissipated, a new disturbance formed near where Lothar had formed. This storm, called Martin, followed a path 200 km south of Lothar and reached its recorded minimum pressure of 964 hPa. Its winds were at maximum intensity as it approached the French coast on the evening of December 27, comparable to those of Lothar: 190 km/h on the coasts and 158 km/h inland.
Storm Martin then struck France and central Europe from 26 to 28 December 1999. At the end of January 2000 two additional damaging storms crossed Denmark and the northern part of Germany.
After the problems of the great storm of 1987, European meteorological services greatly improved their numerical weather prediction models, and Météo-France predicted Lothar. However, cyclone Lothar was not well predicted, with one meteorologist later claiming that forecasts could be split into those that were poor and those that were very poor.