A persistent rex block is ongoing over western Europe. As the cutoff upper low over the western Mediterranean slowly fills, a new push from the west produces a new cutoff low over western Europe by early in the second half of the week. Another round of cool, unsettled weather for western Europe and western and central Mediterranean.
An impressive rex block has established over Europe, with a large cutoff upper low over the Iberian Peninsula and western Mediterranean. The cutoff low has caused severe thunderstorms and intense snowfall in Spain on Saturday and severe thunderstorms in southern France and snowfall in the Algerian desert on Sunday and is producing thunderstorms and torrential rainfall in southern France today as well as heavy snowfall in southwestern Alps and intense advection of Saharan dust far north into central Europe and even as far north as Scandinavia.
500 mbar height anomaly map valid early on Friday, showing the general pattern over Europe. Map: Pivotal Weather.
As the cutoff low slowly fills, a new broad zone of low pressure pushes into western Europe from the Mediterranean. By early Thursday it forms a rather compact, deep cutoff low over southern UK / northwestern France, rapidly moving into the western-central Mediterranean by early Friday. Meanwhile, the broad and strong anticyclone over northern Europe remains, forming another rex block pattern.
500 mbar height anomaly maps showing pattern evolution over Europe over the next several days by Friday. Map: Pivotal Weather.
An associated surface cyclone will likely develop over the Bay of Biscay on Wednesday and Thursday, affecting the region, particularly the coast of western France with gale to storm force winds.
Surface winds across Europe early on Thursday, indicating a surface cyclone just south of the British Isles and Ireland. ARPEGE model guidance. Map: Wxcharts.eu.
A new round of snowfall is coming for northern Spain and the Pyrenees, as well as the Apennines. More on this in the coming days.