Feb 092014
 

An upper front and jetstreak, associated with a rapid shortwave trough crossing Tasmania, helped whip up strong, hot northwesterly surface winds on Sunday, causing extreme fire dangers with active fires in central and eastern Victoria.

WeatherTheatre SceneOne Analysis captured the upper front west of Tasmania at 9-2-2014-0Z, revealed as a tropopause fold extending some two-thirds the depth of the troposphere.

WeatherTheatre SceneOne 9-2-2014-00z, Australia, Top Down View

WeatherTheatre SceneOne 9-2-2014-00z, Australia, Top Down View. An elongated well in the tropopause surface indicates the shortwave trough, at this time just west of Tasmania. Red shadings show the strongest winds, associated with the jetstreak.

WeatherTheatre SceneOne 9-2-2014-00z, Australia, Northerly View

WeatherTheatre SceneOne 9-2-2014-00z, Australia, Northerly View. In the foreground, the upper front is revealed where the tropopause (upper) surface folds into an elongated tubular sheath, enveloping an elevated 300K Theta (lower) surface. Red shadings on the tropopause indicate the strongest winds associated with the jetstreak. Blue shadings on the 300K Theta (lower) surface indicate the coldest air while red shadings the warmest air.

Jan 072014
 

WeatherTheatre SceneOne captures Tropical Cyclone Christine, not long before it crossed the Northwest Australian coast.  TC Christine stands out as a slender vorticity tube, coloured by wind speed, near the Northwest Australian coast on the 30-12-2013-18z SceneOne analysis.  The strongest winds are lower down the in atmosphere, as is typical for warm cored tropical cyclones (via the thermal wind relation).

WeatherTheatre SceneOne 30-12-2013-18z, Australia, Vertical Southeasterly View

WeatherTheatre SceneOne 30-12-2013-18z, Australia, Vertical Southeasterly View. Tropical Cyclone Christine stands out as a slender vorticity tube, shaded by wind speed, in the foreground.

Dec 052013
 

A burst of unseasonal, wintry weather is sweeping across southeast Australia due to a strong, upper cold front in association with a shortwave disturbance crossing the region. The front is triggering widespread rain, thunderstorms and mountain snowfalls.

The WeatherTheatre SceneOne, 4-12-2013-12z analysis, vertical views reveal a deep, narrow tropopause fold along the upper front enveloping a peak in the theta surface where cold polar air is situated behind it.  A narrow elliptical, polar jet filament on the planar view is characteristic of the short wavelength of this disturbance.

Surface cyclogensis is occurring in response to the upper front and strong thermal gradient over southeast Australia.  Forecast models indicate a surface low forming near the southern NSW coast rapidly developing and moving southeast across the Tasman Sea in the next 24 hours.

WeatherTheatre SceneOne 4-12-2013-12z Australia Southeasterly View

WeatherTheatre SceneOne 4-12-2013-12z Australia Southeasterly View. A deep, narrow, curved tropopause fold (upper surface) revealing the upper front envelopes the 300K theta (lower) surface, indicating the associated cold 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).

WeatherTheatre SceneOne 4-12-2013-12z Australia Top-down View

WeatherTheatre SceneOne 4-12-2013-12z Australia Top-down View. A narrow shortwave trough associated with the upper cold front moving over southeast Australia is revealed by the sharply curved, positively tilted, elliptical polar jet filament, seen in the red shadings on the tropopause, which merges with the subtropical jet at the apoapsis. 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 4-12-2013-12z Australia Westerly Vertical View

WeatherTheatre SceneOne 4-12-2013-12z Australia Westerly Vertical View. The upper front features prominently on the left of the image where it is revealed by a tropopause fold enveloping a mounded theta surface associated with the cold 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).

WeatherTheatre SceneOne 4-12-2013-12z Australia Northerly Vertical View

WeatherTheatre SceneOne 4-12-2013-12z Australia Northerly Vertical View. A cut-away view of the upper front stands out in the foreground, showing the theta mound in the centre surrounded by a folded tropopause in the frontal zone. 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 strong, upper cold front is situated south of Australia, in the background of the WeatherTheatre SceneOne, 3-12-2013-0z Analysis, Southerly View.  The front is marked by a deep tropopause fold and associated elevated theta surface behind, indicating a good depth and spread of cold air following.

A tongue of warm air stretches across Southeast Australia preceding the front, reflected in the valley in the 300K Theta surface, where the intersection with the surface corresponds to the 27 degree celcius isotherm.  Forecast models project widespread rain across Southeast Australia ahead of the front and the cold-air behind the front should bring unseasonal snowfalls to the Southeast Australia mountains on Thursday, 5th.

A tropopause lowering over the Tasman Sea, seen on the left side of SceneOne and coming into view in the last few frames of the Southerly to Westerly Orbital View, is associated with a cut-off low which is expected to gradually weaken in the next two days.

WeatherTheatre SceneOne 3-12-2013-0z Southerly to Westerly Orbital View.

WeatherTheatre SceneOne 3-12-2013-0z Southerly to Westerly Orbital View. A strong upper cold front appears south of the continent in the first few frames. A cut-off upper low over the Tasman, which is also driving a cut-off surface low, comes into scene in the last few frames as a lowered tropopause in the top 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 3-12-2013-0z Southerly View

WeatherTheatre SceneOne 3-12-2013-0z Southerly View. A strong, upper cold front stands out in the background, apparent by the folded tropopause (upper surface), shaded red due to the strong jetstream winds associated with the front. The fold wraps around a large mound in the 300K Theta surface below which provides an indication of the depth and spread of the cold 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).

Nov 292013
 

An upper cold front has passed across Tasmania overnight, rapidly moving over the Tasman Sea towards New Zealand today.  A broad tropopause ‘curtain’ fold, dramatically illustrating the front, hangs over the Tasman Sea in the 28-11-2013-18z, WeatherTheatre SceneOne Australia snapshots. The heaped up Theta surface below shows the extent of the associated cold air.

WeatherTheatre SceneOne 28-11-2013-18z Snapshot

WeatherTheatre SceneOne 28-11-2013-18z Westerly Perspective Snapshot. A heaped-up Theta (lower surface) mound illustrates the extent of the cold air associated with the upper cold front, identified by the tropopause curtain situated immediately above. 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 28-11-2013-18z Snapshot

WeatherTheatre SceneOne 28-11-2013-18z Top-down Perspective Snapshot. The valley in the tropopause marks an upper cold front crossing the Tasman Sea. Red shadings correlate with the strongest winds. Conversely, blue shadings correlate with the weakest winds.

WeatherTheatre SceneOne 28-11-2013-18z Snapshot

WeatherTheatre SceneOne 28-11-2013-18z Southeasterly Perspective Snapshot. The curtain appearance of the tropopause (upper surface) in the background signifies an upper cold front crossing the Tasman Sea. 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 strong upper front is nearing Tasmania and features prominently in the 27-11-2013-18z, WeatherTheatre Analysis, snapshot.  The front is made apparent by a deeply folded tropopause (upper surface), seen in the background of the Southeasterly Perspective below.  As a result, rapid cyclogensis is occurring with a surface low quickly deepening.  Most forecast models show the low situated east of Tasmania by Thursday night.

WeatherTheatre 27-11-2013-18z Snapshot

WeatherTheatre 27-11-2013-00z Southeasterly Perspective, showing a strong front near Tasmania, apparent by the folded tropopause (upper surface) and consequently raised Theta (lower) surface, indicating cold air. An upper trough over Western Australia can be seen as a slender vorticity tube, suspended from the surface above, in the right foreground.  Thin cyclonic-vorticity filaments, suspended in the foreground are due to Ex-Tropical Cyclone Alessia.  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).

A small upper trough over Western Australia, marked by a tropopause vorticity-tube extending down from the surrounding tropopause surface above, can be seen in the right of the snapshot.

Thin filaments of cyclonic-vorticity, visible in the foreground, are due to a Ex-Tropical Cyclone Alessia which is located over the Gulf Country.

Nov 272013
 

The WeatherTheatre, 26-11-2013-12z, Australia, Analysis snapshots feature a strong upper front over the Tasman Sea, where the sub-tropical and polar jetstreams are merging.  Darker shadings on the top-down perspective show the steepness of the tropopause in this region, which is prominent in the upper left of the south-easterly perspective snapshot. A tiered, folding, tropopause surface indicates the merging jetstreams in the frontal region. The polar jet is associated with the lower tier and the subtropical jet the higher tier.

WeatherTheatre 26-11-2013-12z Snapshot

WeatherTheatre 26-11-2013-12z top-down snapshot.  A strong upper front over the Tasman features prominently in the darker red shadings at the right of the image.  A weakening upper trough over central Australia, apparent by the tunnel in the surface, is near the centre.  On the far left, another upper trough, apparent by another tunnel in the surface, is entering the scene.  A strong upper front, well south of the continent, is visible in the red shadings near the bottom left. 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).

 

 

A weakening upper trough, which has been supporting a surface low over Western Australia, appears near the centre of the top-down perspective as a tunnel in the tropopause surface. Another upper trough can be seen to its west and will effect Western Australia over the next 24 hours.

 

A strong upper front in the polar jet, situated well south of the continent, appears in the right background of the south-easterly perspective snapshot. This is one to watch over the next 24-48 hours as it should cause the formation of a deep surface low east of Tasmania on Thursday evening.

WeatherTheatre 26-11-2013-12z Snapshot

WeatherTheatre 26-11-2013-12z South-easterly Snapshot.  The strong upper front over the Tasman Sea features prominently as the deep fold of the tropopause (upper sruface) in the left of the image.  An upper trough over central Australia shows up near the centre foreground.  A strong upper front well south of the continent is seen by the lowering in the right background.  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 262013
 
WeatherTheatre 25-11-2013-18z Snapshot

WeatherTheatre 25-11-2013-18z snapshot, south-westerly perspective.  A disturbance in sub-tropical jet over Western Australia is visible in the upper right foreground (upper surface) and a mid-latitude disturbance behind it.  Red shadings correlate with the strong winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and coldest temperatures (lower surface).

WeatherTheatre 25-11-2013-18z Snapshot
WeatherTheatre 25-11-2013-18z snapshot, easterly perspective. The tropopause front over Western Australia is seen in the mid-foreground (upper surface), while the mid-latitude front is seen on the far right. A disturbance persisting over the Tasman Sea is visible in the background.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and cold temperatures (lower surface).

WeatherTheatre 25-11-2013-18z Snapshot
WeatherTheatre 25-11-2013-18z snapshot, south-easterly perspective. The disturbance over the Tasman Sea features prominently. Tiered tropopause (upper surface) folding is occurring as the polar jet merges with the sub-tropical jet, creating a stepped appearance to the tropopause.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures (lower surface).  Conversely, blue shadings correlate with the weakest winds (upper surface) and coldest temperatures (lower surface).

A small disturbance in the sub-tropical jetstream over Western Australia features prominently in this morning’s WeatherTheatre Analysis, at 25-11-2013-18z. It can be seen in the adjacent WeatherTheatre snapshot as a tropopause front with a trailing vorticity tube to the mid-troposphere.  The disturbance is assisting a surface low over the Gascoyne/Pilbara region.

A mid-latitude upper front in its mature phase is apparent in a tropopause fold seen south of Western Australia in the background of the south-westerly perspective snapshot.  The easterly perspective snapshot shows it on the far right side.

In the background of the easterly perspective snapshot, a persistent upper disturbance and associated tropopause folding situated over the Tasman Sea is visible.  This is better seen in the south-easterly snapshot which shows a tiered appearance to the folding, due to the polar jetstream merging with the subtropical jetstream over the eastern Tasman.

The top-down perspective below provides a good indication of the geographic layout and extent of the features described.  The two disturbances in the west are visible on the left with darker shadings indicating the steepness of the tropopause surface in the frontal regions.

 

 

WeatherTheatre 25-11-2013-18z Snapshot

WeatherTheatre 25-11-2013-18z snapshot, top-down perspective.  The merging of the polar and sub-tropical jets is evident over the eastern Tasman in the far right. The disturbance in the sub-tropical jet over Western Australia is seen on the mid-left side and the disturbance south of Western Australia on the lower left.  Red shadings correlate with the strongest winds (upper surface and vectors) and warmest temperatures.  Conversely, blue shadings correlate with the weakest winds (upper surface and vectors) and coldest temperatures (lower surface).