Precipitation type transition regions in winter storms over southern Ontario

Stewart, Ronald E.; King, Patrick

doi:10.1029/jd095id13p22355

Cited by 17 publications

(6 citation statements)

References 32 publications

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“…Ryzhkov and Zrnic (1998) associated these signatures with the rain-snow transition zone, as corroborated by precipitation-type observations near OUN during the period 1900-2000 UTC. Drawing on transition-zone conceptual models described by Stewart and King (1990) and Stewart (1992), Ryzhkov and Zrnic explained that (i) the peak Z DR (and K DP ) prior to the transition from rain to snow is due to the presence of large, oblate raindrops; (ii) the pronounced dip in HV essentially within the transition zone owes to a large spread in the distribution of hydrometeor types and sizes (Doviak and Zrnic 1993, 264-266); and (iii) the peak in Z H just after the transition responds to the aggregates of effectively large diameter found in this region. The reflectivity band in Figs.…”

Section: Reflectivity Band and The Rain-snow Transitionmentioning

confidence: 99%

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Multiscale Structure and Evolution of an Oklahoma Winter Precipitation Event

Trapp¹,

Schultz²,

Ryzhkov³

et al. 2001

Mon. Wea. Rev.

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A significant winter precipitation event occurred on 8-9 March 1994 in Oklahoma. Snow accumulations greater than 30 cm (12 in.) were measured within a narrow corridor in northern Oklahoma. On the synoptic scale and mesoscale, a correspondence between large snow accumulations and 600-hPa frontogenesis was revealed; the precipitation was formed above the cold frontal surface, owing to midtropospheric ascent associated with the cross-frontal circulation in a region of elevated conditional instability. The location of such a narrow corridor of large accumulations was not, however, disclosed by any patterns in the radar reflectivity data. Indeed, during this event, an elongated maximum of snow accumulation was not associated with a persistent ''band'' of enhanced reflectivity and vice versa. Dual-polarization and dual-Doppler radar data allowed for a novel analysis of winter precipitation processes and structures, within the context of the larger-scale diagnosis. It was possible to identify, in order of distance southward toward the surface cold front: (i) an elevated convective element, which was classified as an elevated thunderstorm and may have functioned as an ice crystal ''generator'' cell, embedded within a broad region of generally stratiform precipitation; (ii) a reflectivity band and associated rain-snow transition zone, the evolution and structure of which apparently were coupled to the effects of melting precipitation and strong vertical wind shear; and (iii) a mixed-phase precipitation-generating, prolific lightning-producing, nonelevated thunderstorm cell that was sustained in the postfrontal air in part by virtue of its rotational dynamics.

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Section: Reflectivity Band and The Rain-snow Transitionmentioning

confidence: 99%

“…11 and 12 can be interpreted as a horizontal segment of a ''vertical bright band'' (VBB). In essence, the VBB is a manifestation of the mixed-phase precipitation generated within the rain-snow transition zone (Stewart and King 1990, their Fig. 15).…”

Section: Reflectivity Band and The Rain-snow Transitionmentioning

confidence: 99%

Multiscale Structure and Evolution of an Oklahoma Winter Precipitation Event

Trapp¹,

Schultz²,

Ryzhkov³

et al. 2001

Mon. Wea. Rev.

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“…4). Stewart and King (1990) also noted reflectivity bright bands below the 0ЊC level in an Ontario winter storm. There are no large echoes with strong reflectivities and isolated cores that are typically expected with thunderstorms.…”

Section: Time (Utc/date)mentioning

confidence: 99%

“…Colman ( 1990a,b ) dynamic and thermodynamic environments of elevated thunderstorms in the eastern United States on the cold side of fronts. Stewart and King ( 1990 ) considered the region separating frozen from liquid precipitation in southern Ontario; thunder was heard by observers in one of two cases. Galway and Pearson ( 1981 ) focused on winter tornadoes in the central United States that usually had widespread blizzards, heavy snow, and / or extensive glazing on the cold side of the weather systems.…”

Section: Introductionmentioning

confidence: 99%

Lightning during Two Central U.S. Winter Precipitation Events

Holle

Watson

1996

Wea. Forecasting

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Network-detected cloud-to-ground lightning coincident with mainly frozen precipitation (freezing rain, sleet, snow) was studied over the central United States during two outbreaks of arctic air in January 1994. During the first event, the ratio of positive to total flashes was 59%, flashes were few and disorganized in area, and no surface observer reported thunder. For the other event the ratio was 52% during the first few hours in subfreezing surface air, then decreased when flashes formed in the nearby region above freezing. Also, flashes in this case were linearly aligned and coincided with conditional symmetric instability; thunder was heard infrequently by surface observers. On radar, reflectivity cores grew from weak to moderate intensity within a few hours of the lightning during both cases. Echo area increased greatly before flashes in one case, while the area increase coincided with flashes in the other. Some base-scan reflectivities were strong in both thunderstorm regions due to the radar beam intersecting the melting level. Regions with lightning often could be identified better by high echo tops than reflectivity. Analyses on the scale of one or two states diagnosed the strength of low-level warming that contributed to formation of thunderstorms and significant frozen precipitation. Quasigeostrophic analyses showed that 850-mb temperature advection and 850-500-mb differential vorticity advection were similar in magnitude in the lightning area during both events. Once convection formed, lightning and echo-top information identified downstream regions with a potential for subsequent frozen precipitation.

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“…13). This feature possibly indicates the presence of another mesoscale structurea vertical bright band (Stewart and King, 1990).…”

Section: Case 3 Mesoscale Analysis In Synoptic-scale Stormsmentioning

confidence: 99%

The king city operational doppler radar: Development, all‐season applications and forecasting

et al. 1991

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In 1985, the first Doppler weather radar to operate in Canada was established by the Research Directorate of the Atmospheric Environment Service (AES) at a site in IntroductionThe King City weather radar facility located north of Toronto, Ontario, was established as a research centre by the Atmospheric Environment Service for cloud physics and radar meterology in 1985. It is the first Doppler radar system to be designed and operated in Canada specifically for the weather observing role. The system was developed from hardware components that were commercially available and by in-house design of interfacing and software. Over the past several years, a program of research and development of the system and its applications has progressed to the point where the system output has been fully integrated into the operational program of the Ontario Weather Centre, which provides full weather services to their forecast region. At the same time, a broad research and development program continues, with the emphasis on meteorological applications. A close liaison of the research and operational sectors has allowed the immediate transfer of technology into operations with mutual benefits.

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Precipitation type transition regions in winter storms over southern Ontario

Cited by 17 publications

References 32 publications

Multiscale Structure and Evolution of an Oklahoma Winter Precipitation Event

Multiscale Structure and Evolution of an Oklahoma Winter Precipitation Event

Lightning during Two Central U.S. Winter Precipitation Events

The king city operational doppler radar: Development, all‐season applications and forecasting

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