The Morning Glory: An extraordinary atmospheric undular bore (original) (raw)

The Causes of Fog at Maddens Plain, N.S.W., 1975-1990

Add-Ed Studies in Geography, 2017

Daytime fog at Maddens Plain along the Illawarra escarpment south of Sydney between 1975-1990 can be related either to expansive cooling of air directed onshore against the escarpment, or to cloud under conditions of convective instability. Because of ground drainage, radiation fogs rarely persist into daytime. Principal component analysis of a suite of regional and local meteorological variables and fog parameters indicates that fog is related to the presence of macro-scale circulation, namely east coast lows, the passage of cold fronts or monsoonal intrusions of low pressure over the interior of New South Wales. The development and persistence of these lows are linked inseparably to the positioning and movement of anticyclonic cells across the continent. Surprisingly there appears to be little consistent relationship of either fog characteristics or the synoptic patterns favouring fog formation to phases of the Southern Oscillation.

The Vertical Vorticity Structure within a Squall Line Observed during BAMEX: Banded Vorticity Features and the Evolution of a Bowing Segment

Monthly Weather Review, 2015

A quasi-linear convective line with a trailing stratiform region developed during the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) while being sampled by two airborne Doppler radars. The finescale reflectivity and Doppler velocities recorded by the radars documented the evolution of the convective line. Bands of positive and negative vertical vorticity oriented parallel to the convective line were resolved in the analysis. This type of structure has rarely been reported in the literature and appears to be a result of the tilting and subsequent stretching of ambient horizontal vorticity produced by the low-level wind shear vector with a significant along-line component. The radar analysis also documented the evolution of an embedded bow echo within the convective line. Embedded bow echoes have been documented for a number of years; however, a detailed analysis of their kinematic structure has not been previously reported in the literature. The counterrotating circulati...