A Satellite-Derived Classification Scheme for Rapid Maritime Cyclogenesis

Evans, Michael S.; Keyser, Daniel; Bosart, Lance F.; Lackmann, Gary M.

doi:10.1175/1520-0493(1994)122<1381:asdcsf>2.0.co;2

Cited by 50 publications

(40 citation statements)

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“…These results are consistent with conceptual models of cyclogenesis determined observationally by Evans et al (1994), Young (1995), and Sinclair and Revell (2000). The fact that jet-entrance and jet-exit regions are favoured regions for cyclogenesis is a strong argument for considering zonal variations in the horizontal wind speed as a possible explanation for cyclone variability.…”

Section: Introductionsupporting

confidence: 89%

“…These authors have employed observational (e.g. McCallum and Norris, 1990;Evans et al, 1994;Young, 1995;Hartmann, 1995;Schultz et al, 1998;Simmons, 1999;Shapiro et al, 1999;Sinclair and Revell, 2000;Shapiro et al, 2001;Martius et al, 2007) and idealized numerical-modelling (e.g. Davies et al, 1991;Thorncroft et al, 1993;Wernli et al, 1998;Hartmann and Zuercher, 1998;Schultz et al, 1998) (Shapiro and Keyser, 1990, figure 10.27), enhancing the zonal elongation of the cyclone and fronts and reflecting the continued existence of the frontal T-bone in stage IV.…”

Section: Introductionmentioning

confidence: 99%

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Baroclinic development within zonally‐varying flows

Schultz

Zhang

2007

Quart J Royal Meteoro Soc

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Previous idealized-modelling studies have shown the importance of across-jet barotropic shear to the resulting evolution of cyclones, anticyclones, surface-based fronts, and upper-level fronts. Meanwhile, many observational studies of cyclones have shown the importance of along-jet variations in the horizontal wind speed (i.e. confluence and diffluence). This study investigates the importance of these along-jet (zonal, for zonally-oriented jets) variations in the horizontal wind speed to the resulting structures and evolutions of baroclinic waves, using idealized models of growing baroclinic waves. An idealized primitive-equation channel model is configured with growing baroclinic perturbations embedded within confluent and diffluent background flows. When the baroclinic perturbations are placed in background confluence, the lower-tropospheric frontal structure and evolution initially resemble the Shapiro-Keyser cyclone model, with a zonallyoriented cyclone, strong warm front, and bent-back warm front. Later, as the baroclinic wave is amplified in the stronger downstream baroclinicity, the warm sector of the cyclone narrows, becoming more reminiscent of the Norwegian cyclone model. The upper-level frontal structure develops with a southwest-northeast orientation, and becomes strongest at the base of the trough, where geostrophic cold advection is occurring. In contrast, when the baroclinic perturbations are placed in background diffluence, the lower-tropospheric frontal structure and evolution resemble the Norwegian cyclone model, with a meridionally-oriented cyclone, strong cold front, and occluded front. The upper-level frontal structure is initially oriented northwest-southeast on the western side of the trough, before becoming zonally oriented. Weak geostrophic temperature advection occurs along its length. These results are compared to those from previous observational and idealized-modelling studies.

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Section: Introductionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Baroclinic development within zonally‐varying flows

Schultz

Zhang

2007

Quart J Royal Meteoro Soc

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“…Given appropriate environmental conditions, perturbations on fronts can grow and extract energy from the wind shear. This is predicted by theory (Charney and Stern 1962;Schär and Davies 1990) and observed in satellite images (Evans et al 1994) and numerical analyses (e.g., Joly and Thorpe 1990;Thorncroft and Hoskins 1990).…”

Section: Introductionsupporting

confidence: 52%

Diagnosis of Frontal Instabilities over the Southern Ocean

2005

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The development of three fronts over the Southern Ocean is described using SeaWinds-on-QuikSCAT scatterometer surface winds and an attribution technique to partition the wind field in three components: nondivergent and irrotational components at the scale of the front, and the remaining harmonic component (or environmental flow) induced by the synoptic-scale flow. The front and the environment in which the front is embedded are analyzed separately.A frontal wave is shown to develop out of the first front when the large-scale alongfront stretching decreases, the environmental flow becomes frontolytic, and a connection with the upper levels is established. In the second case, the stretching remains relatively strong and no frontal wave develops. The third front exhibits a developing wave but is not in a favorable configuration with the upper levels; the frontal wave does not deepen significantly.

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“…Indeed, there are techniques to identify the genesis and subsequent development of cyclones based on the appearance of distinctive cloudrelated signatures in satellite imagery (Evans et al 1994). Thus, one must presume that cloud-diabatic effects play a part in the development of most observed cyclones.…”

Section: Introductionmentioning

confidence: 99%

The Integral Role of a Diabatic Rossby Vortex in a Heavy Snowfall Event

Moore

Montgomery

Davies

2008

Monthly Weather Review

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On 24-25 February 2005, a significant East Coast cyclone deposited from 4 to nearly 12 in. (ϳ10-30 cm) of snow on parts of the northeastern United States. The heaviest snowfall and most rapid deepening of the cyclone coincided with the favorable positioning of an upper-level, short-wave trough immediately upstream of a preexisting surface cyclone. The surface cyclone in question formed approximately 15 h before the heaviest snowfall along a coastal front in a region of frontogenesis and heavy precipitation. The incipient surface cyclone subsequently intensified as it moved to the northeast, consistently generating the strongest convection to the east-northeast of the low-level circulation center. The use of potential vorticity (PV) inversion techniques and a suite of mesoscale model simulations illustrates that the early intensification of the incipient surface cyclone was primarily driven by diabatic effects and was not critically dependent on the upper-level wave. These facts, taken in conjunction with the observed structure, energetics, and Lagrangian evolution of the incipient surface disturbance, identify it as a diabatic Rossby vortex (DRV). The antecedent surface vorticity spinup associated with the DRV phase of development is found to be integral to the subsequent rapid growth. The qualitative similarity with a number of observed cases of explosive cyclogenesis leaves open the possibility that a DRV-like feature comprises the preexisting positive low-level PV anomaly in a number of cyclogenetic events that exhibit a two-stage evolution.

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A Satellite-Derived Classification Scheme for Rapid Maritime Cyclogenesis

Cited by 50 publications

References 0 publications

Baroclinic development within zonally‐varying flows

Baroclinic development within zonally‐varying flows

Diagnosis of Frontal Instabilities over the Southern Ocean

The Integral Role of a Diabatic Rossby Vortex in a Heavy Snowfall Event

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