Jan 092014
 

Much of the central, northern and eastern US and Canada is in the grip of a deep freeze, experiencing the coldest temperatures in decades, due to a deep polar upper low.  WeatherTheatre SceneOne gives a 3D perspective of the evolution and progression of this winter storm, also called a ‘polar vortex’.

WeatherTheatre SceneOne 3-1-2014-12z, North America, Top Down View

WeatherTheatre SceneOne 3-1-2014-12z, North America, Top Down View. An upper shortwave trough, indicated by the sharp u-shaped curvature in the jetstream along the tropopause surface in the right half of the image, shows the first wave of cold air to affect the central-eastern US. At this time, the cold air was peaking over the northeast US. Red shadings indicate the strongest winds on the tropopause while blue shadings the lightest. The 300K Theta surface partially obscures the tropopause near the top of the image, where its height is greater. The blue shading is indicative of the cold polar air mass in this region.

WeatherTheatre SceneOne 6-1-2014-00z, North America, Top Down View

WeatherTheatre SceneOne 6-1-2014-00z, North America, Top Down View. The large u-shaped valley in the tropopause represents the second wave of cold air to affect the US, longer in wavelength than the initial cold snap, and responsible for the coldest temperatures in decades. The red shadings indicate the strongest winds, associated with the jetstream. The dark blue shadings near the top indicate cold temperatures of the 300K Theta surface, which is overlapping and obscuring the tropopause.

 

 

 

 

 

 

 

 

 

 

 

The icy storm complex began shortly after New Year, 2014, with a shortwave upper trough sweeping over central-eastern states. This was then followed by a longer-wave trough associated with the ‘polar vortex’, bringing frigid conditions across much of the US. The only areas to escape were along the west coast and the far south.

WeatherTheatre SceneOne 3-1-2014-12z, North America, Westerly Vertical View

WeatherTheatre SceneOne 3-1-2014-12z, North America, Westerly Vertical View of the first cold wave, showing a deep tropopause (upper surface) fold along the wave front, shaded red due to the intense winds associated with the jetstream in this region.

WeatherTheatre SceneOne 3-1-2014-12z, North America, Northeasterly Vertical View

WeatherTheatre SceneOne 3-1-2014-12z, North America, Northeasterly Vertical View, looking along the axis of the shortwave trough responsible for the first frigid weather across central-eastern states. 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 7-1-2014-00z, North America, Top Down View

WeatherTheatre SceneOne 7-1-2014-00z, North America, Top Down View. The second and longer wavelength upper trough responsible for the coldest temperatures in decades is seen in the u-shaped tropopause valley. The red shadings indicate intense jetstream winds. The blue shaded 300K Theta surface obscures the tropopause in the valley region.

Dec 042013
 

Plummeting temperatures, heavy snowfalls and freezing winds are blasting the NW USA as a strong winter front progresses east.

A deep, tropopause fold envelopes and intersects with a steep, mountainous, Theta surface, revealing a vigorous Arctic cold front, slicing through most of the troposphere, in the WeatherTheatre SceneOne 4-12-2013-0z Northeasterly View.

The typical upward slope of the Theta surface from tropics to polar regions is apparent at zonal points in the WeatherTheatre Orbital Sweep, culminating in a steep ascent in the frontal region.

The front is inducing surface cyclogenesis with most forecast models indicating a low over Colorado will drift northeast and rapidly deepen in the next 48 hours.

WeatherTheatre SceneOne 4-12-2013-0z Orbital Sweep

WeatherTheatre SceneOne 4-12-2013-0z North America Orbital Sweep.  A strong front ‘hangs’ over the NW USA, showing up as a curtain fold of the tropopause (upper surface).  Typical meridional upward slope of the Theta (lower) surface from tropics to polar regions is apparent at zonal points of the sweep, with a notable steep ascent near the front.  The frontal fold intersects with the Theta surface and this is apparent from northerly points (looking south) in the sweep where bits of the tropopause can be seen beneath the Theta surface.  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 4-12-2013-0z Northeasterly View

WeatherTheatre SceneOne 4-12-2013-0z Northeasterly View. A strong Arctic front is vividly revealed by a deep tropopause fold (upper surface), partially obscuring a mountainous theta surface which is indicative of a polar atmosphere. 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 032013
 

A deep, winter cold front is sweeping over the NW USA from Canada and the NW Pacific, bringing a blast of Arctic air with widespread snowfalls.  The WeatherTheatre SceneOne, 2-12-2013-12z Analysis, dramatically illustrates the front responsible for the icy weather.  The front is marked by a deep folded tropopause, extending through most of the depth of the troposphere and dominating the centre field of view.  A steeply sloping, high theta surface intersects the fold, indicating the depth and extent of the frigid Arctic air following the front.

WeatherTheatre SceneOne 2-12-2013-12z East-Northeasterly View

WeatherTheatre SceneOne 2-12-2013-12z East-Northeasterly View. A deep tropopause fold (upper surface) intersects with the 300K Theta (lower surface), associated with a strong blast of Arctic air sweeping over the NW USA. 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).

Nov 282013
 

A vigorous, early-winter season cold front has lead to the rapid development of a deep surface low over the northeast USA, bringing widespread snowfalls.  The front features prominently on 27-11-2013-18z, WeatherTheatre snapshots.  The Top-down Perspective of the tropopause shows a large amplitude, positively tilted, shortwave disturbance on the right side.  A distinctive and dramatic double-fold tropopause ‘curtain’ is apparent on the Northerly Perspective, as the subtropical jet begins to merge with the polar jet at the jetstreak entrance region.  Meanwhile, deep-blue shadings in the background are a very much elevated 300K Theta surface associated with very cold air.

WeatherTheatre 27-11-2013-18z Northerly Perspective Snapshot.

WeatherTheatre 27-11-2013-18z Northerly Perspective Snapshot. A ‘curtain’ tropopause displays twin folds, more distinctive in the foreground, where jetstreams merge.  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 27-11-2013-18z Top-down Snapshot.

WeatherTheatre 27-11-2013-18z Top-down Snapshot.  The large amplitude, shortwave disturbance features prominently on the right, where its associated jetstreak stands out in the red shading.  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).

Nov 272013
 

The WeatherTheatre, 27-11-2013-0z, North American Analysis shows a strong upper front crossing the Northeastern USA, which is driving rapid cyclogenesis and the formation of a deep surface low. The Northwesterly Perspective shows the eastern side of a deep tropopause fold (upper surface), oriented from the southwest to the northeast.  Comparison between the Northeasterly and Northwesterly Perspectives reveals the elongated nature of the front which runs across the eastern USA from the southwest to the northeast.  The raised Theta surface below indicates the spread of the associated cold air.

WeatherTheatre 27-11-2013-00z Snapshot

WeatherTheatre USA, 27-11-2013-00z, Northwesterly Perspective.  The poleward, northeasterly orientation of a strong upper front and tropopause fold (upper surface) across the eastern USA is apparent. 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 27-11-2013-00z Snapshot

WeatherTheatre 27-11-2013-00z USA Northeasterly Perspective. A strong upper front and deep tropopause fold (upper surface) dominates 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).