A Case Study of Lid Evolution Using Analyses of Observational Data and a Numerical Model Simulation

Lanicci, John M.; Warner, Thomas T.

doi:10.1175/1520-0434(1997)012<0228:acsole>2.0.co;2

Cited by 8 publications

(3 citation statements)

References 23 publications

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“…This layer forms as a Pacific cold front passes over the Rocky Mountains, and the air behind the front, which is already somewhat destabilized by surface heat fluxes over the northeastern Pacific Ocean, experiences enhanced boundary layer mixing due to the underlying rough terrain and increased insolation in the generally cloud-free region over leeward of the mountain crest. In contrast, the lower tropo- spheric air east of the lee trough is typically associated with a southerly return flow (Lanicci and Warner 1997) from a polar air mass that had previously moved southward toward the Gulf of Mexico. Although such air masses have enhanced moisture content and high equivalent potential temperature, they are typically capped by strong static stability.…”

Section: The Slope Of An Occluded Frontmentioning

confidence: 99%

Warm Occlusions, Cold Occlusions, and Forward-Tilting Cold Fronts

Stoelinga¹,

Locatelli²

2002

Bull. Amer. Meteor. Soc.

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A relationship between the slope of a front and the static stability contrast across the front provides new insights into warm and cold occlusions and forward-tilting cold fronts. O ver the past decade or so, the classical occlusion hypothesis (Bjerknes and Solberg 1922) has had a significant revival due to its validation by modern mesoscale meteorological research. This revival followed a period of decline that culminated around 1990 with near-complete rejection of the idea. Bjerkens and Solberg originally described a process by which, during the middle to late part of the life cycle of a midlatitude frontal cyclone, the cold front catches up to the warm front and occludes with it, leaving an occluded front as the interface between the two cold air masses that were earlier ahead of the warm front and behind the cold front, and detaching the warm sector air from the surface. This process is part of what is now known as the Norwegian model for the life cycle of extratropical cyclones. In the latter half of the twentieth century, several key research papers and textbooks (e.g.

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Section: The Slope Of An Occluded Frontmentioning

confidence: 99%

Warm Occlusions, Cold Occlusions, and Forward-Tilting Cold Fronts

Stoelinga¹,

Locatelli²

2002

Bull. Amer. Meteor. Soc.

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“…However, more central to this work is advancing the fundamental understanding of environments that can lead to tornado development during winter months (e.g., Sherburn and Parker 2014;King et al 2017). Of particular interest is the influence that the temperature of a moisture source has on downstream thermodynamic buoyancy and convection (Edwards and Weiss 1996;Lanicci and Warner 1997;Evans and Guyer 2006;Guyer et al 2006). This relationship can be evaluated by exploring the sensitivity of the 21-23 January 2017 tornado outbreak to temperatures of nearby moisture sources using a series of model simulations.…”

Section: Introductionmentioning

confidence: 99%

Moisture Attribution and Sensitivity Analysis of a Winter Tornado Outbreak

Molina

Allen

Prein

2020

Weather and Forecasting

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The tornado outbreak of 21–23 January 2017 caused 20 fatalities, more than 200 injuries, and over a billion dollars in damage in the Southeast United States. The event occurred concurrently with a record-breaking warm Gulf of Mexico (GoM) basin. This article explores the influence that warm GoM sea surface temperatures (SSTs) had on the tornado outbreak. Backward trajectory analysis, combined with a Lagrangian-based moisture-attribution algorithm, reveals that the tornado outbreak’s moisture predominantly originated from the southeast GoM and the northwest Caribbean Sea. We used the WRF Model to generate a control simulation of the event and explore the response to perturbed SSTs. With the aid of a tornadic storm proxy derived from updraft helicity, we show that the 21–23 January 2017 tornado outbreak exhibits sensitivity to upstream SSTs during the first day of the event. Warmer SSTs across remote moisture sources and adjacent waters increase tornado frequency, in contrast to cooler SSTs, which reduce tornado activity. Upstream SST sensitivity is reduced once convection is ongoing and modifying local moisture and instability availability. Our results highlight the importance of air–sea interactions before airmass advection toward the continental United States. The complex and nonlinear nature of the relationship between upstream SSTs and local precursor environments is also discussed.

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“…Here, growth of the convective well‐mixed layer is not a sole mechanism for generation of an inversion and CIN. A notable example is the so‐called elevated mixed layer, which is a consequence of advection of warm moist air originating from the Gulf of Mexico to higher latitudes (e.g., Lanicci and Warner, 1997). However, the main point remains the same: regardless of being self‐generated or externally generated, the convective well‐mixed layer continues to grow by penetrating its air into an inversion layer, thus the existence of CIN does not block its growth.…”

Section: Discussionmentioning

confidence: 99%

Initiation of deep convection through deepening of a well‐mixed boundary layer

Yano

2021

Quart J Royal Meteoro Soc

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The present study examines mechanisms by which deep moist convection may be initiated through deepening of well-mixed convective boundary layer under a large-scale low-level convergence.The process is examined using a standard formulation for the well-mixed boundary layer, in which the depth increases exponentially with time under a constant convergence with height. Consideration is also given to a case with a more realistic mean verticalvelocity profile that has a maximum at a middle troposphere and attenuates to zero at the tropopause. In the latter case, the unstable well-mixed layer under convergence grows to a tropospheredeep mixed layer. Importantly, under these scenarios, the socalled convective inhibition (CIN) does not inhibit deepening of a well-mixed convective boundary layer, thus deep moist convection does not need to overcome CIN to initiate, either.

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A Case Study of Lid Evolution Using Analyses of Observational Data and a Numerical Model Simulation

Cited by 8 publications

References 23 publications

Warm Occlusions, Cold Occlusions, and Forward-Tilting Cold Fronts

Warm Occlusions, Cold Occlusions, and Forward-Tilting Cold Fronts

Moisture Attribution and Sensitivity Analysis of a Winter Tornado Outbreak

Initiation of deep convection through deepening of a well‐mixed boundary layer

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