Dec 062013
 

NW Europe is being battered by a powerful winter cold front responsible for severe winds, snowfalls, and heavy rain and flooding.  The WeatherTheatre SceneOne, 5-12-2013-12z, Vertical and Planar Views show a strong upper cold front, signified by a deep tropopause fold, and associated strong polar jet apparent in the red shadings across the NE Atlantic and NW Europe.

The upper front has lead to a deep surface low over southern Norway and steep pressure gradients to the south of the low centre, driving gale force winds.   Forecast models indicate the low rapidly moving across to western Russia by the weekend as the upper front progresses east.

WeatherTheatre SceneOne 5-12-2013-12z, Europe, Vertical Northerly View

WeatherTheatre SceneOne 5-12-2013-12z, Europe, Vertical Northerly View. A deep tropopause fold is notable in the background, shaded red due to a strong polar jetstream. The fold obscures a steep 300K theta surface indicating very cold polar air behind it. Red shadings correlate with the strongest winds (upper surface) and warmest temperatures (lower surface). Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).

WeatherTheatre SceneOne 5-12-2013-12z, Europe, Top-down Planar View

WeatherTheatre SceneOne 5-12-2013-12z, Europe, Top-down Planar View. A strong jetstream (red shadings) is seen entering NW Europe near the top of the view. The tropopause is obscured by the a very high 300K theta surface (the blue area) north of the jet, indicating cold polar air. Red shadings correlate with the strongest winds (upper surface) and warmest temperatures (lower surface). Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).

Dec 022013
 

A cut-off, upper low over the Southern Mediterranean is driving a deep surface low near Sicily, causing widespread heavy rainfalls over the central Mediterranean. The 1-12-2013-18z WeatherTheatre SceneOne Analysis, Northerly Perspective, shows a dramatic tropopause curtain fold (upper surface), wrapping around with the upper low circulation, and an associated raised Theta surface immediately below. Forecast models show the low persisting and slowly moving southeast, then gradually weakening from the 5th.

WeatherTheatre SceneOne 1-12-2013-18z Northerly Perspective Snapshot, showing a cut-off upper low with dramatic tropopause fold near the middle foreground.  Red shadings correlate with the strongest winds (upper surface) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).

WeatherTheatre SceneOne 1-12-2013-18z Northerly Perspective Snapshot, showing a cut-off upper low with dramatic tropopause fold near the centre foreground. Red shadings correlate with the strongest winds (upper surface) and warmest temperatures (lower surface). Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).