Low-Level Mesoscale and Cloud-Scale Interactions Promoting Deep Convection Initiation
Abstract
Data from scanning radars, radiosondes, and vertical profilers deployed during three field campaigns are analyzed to study interactions between cloud-scale updrafts associated with initiating deep moist convection and the surrounding environment. Three cases are analyzed in which the radar networks permitted dual-Doppler wind retrievals in clear air preceding and during the onset of surface precipitation. These observations capture the evolution of (i) the mesoscale and boundary layer flow, and (ii) low-level updrafts associated with deep moist convection initiation (CI) events yielding sustained or short-lived precipitating storms. The elimination of convective inhibition did not distinguish between sustained and unsustained CI events, though the vertical distribution of convective available potential energy may have played a role. The clearest signal differentiating the initiation of sustained versus unsustained precipitating deep convection was the depth of the low-level horizontal wind convergence associated with the mesoscale flow feature triggering CI, a sharp surface wind shift boundary, or orographic upslope flow. The depth of the boundary layer relative to the height of the LFC failed to be a consistent indicator of CI potential. Widths of the earliest detectable low-level updrafts associated with sustained precipitating deep convection were ~3–5 km, larger than updrafts associated with surrounding boundary layermore »
- Authors:
-
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); University of Colorado, Boulder, CO (United States)
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- University of Colorado, Boulder, CO (United States)
- University of Colorado, Boulder, CO (United States); Cooperative Institute for Research in the Atmosphere, Fort Collins, CO (United States); National Weather Service (NWS), Boulder, CO (United States)
- Publication Date:
- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); National Science Foundation (NSF)
- OSTI Identifier:
- 1812317
- Alternate Identifier(s):
- OSTI ID: 1923083; OSTI ID: 1923084
- Report Number(s):
- PNNL-SA-158181
Journal ID: ISSN 0027-0644
- Grant/Contract Number:
- AC05-76RL01830; AGS-1661707; AGS-1541624; AGS-1661662
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Monthly Weather Review
- Additional Journal Information:
- Journal Volume: 149; Journal Issue: 8; Journal ID: ISSN 0027-0644
- Publisher:
- American Meteorological Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES; convective storms; convective-scale processes; mesoscale processes; storm environments; radars; radar observations; soundings
Citation Formats
Marquis, James N., Varble, Adam C., Robinson, Paul, Nelson, T. Connor, and Friedrich, Katja. Low-Level Mesoscale and Cloud-Scale Interactions Promoting Deep Convection Initiation. United States: N. p., 2021.
Web. doi:10.1175/mwr-d-20-0391.1.
Marquis, James N., Varble, Adam C., Robinson, Paul, Nelson, T. Connor, & Friedrich, Katja. Low-Level Mesoscale and Cloud-Scale Interactions Promoting Deep Convection Initiation. United States. https://doi.org/10.1175/mwr-d-20-0391.1
Marquis, James N., Varble, Adam C., Robinson, Paul, Nelson, T. Connor, and Friedrich, Katja. Sun .
"Low-Level Mesoscale and Cloud-Scale Interactions Promoting Deep Convection Initiation". United States. https://doi.org/10.1175/mwr-d-20-0391.1. https://www.osti.gov/servlets/purl/1812317.
@article{osti_1812317,
title = {Low-Level Mesoscale and Cloud-Scale Interactions Promoting Deep Convection Initiation},
author = {Marquis, James N. and Varble, Adam C. and Robinson, Paul and Nelson, T. Connor and Friedrich, Katja},
abstractNote = {Data from scanning radars, radiosondes, and vertical profilers deployed during three field campaigns are analyzed to study interactions between cloud-scale updrafts associated with initiating deep moist convection and the surrounding environment. Three cases are analyzed in which the radar networks permitted dual-Doppler wind retrievals in clear air preceding and during the onset of surface precipitation. These observations capture the evolution of (i) the mesoscale and boundary layer flow, and (ii) low-level updrafts associated with deep moist convection initiation (CI) events yielding sustained or short-lived precipitating storms. The elimination of convective inhibition did not distinguish between sustained and unsustained CI events, though the vertical distribution of convective available potential energy may have played a role. The clearest signal differentiating the initiation of sustained versus unsustained precipitating deep convection was the depth of the low-level horizontal wind convergence associated with the mesoscale flow feature triggering CI, a sharp surface wind shift boundary, or orographic upslope flow. The depth of the boundary layer relative to the height of the LFC failed to be a consistent indicator of CI potential. Widths of the earliest detectable low-level updrafts associated with sustained precipitating deep convection were ~3–5 km, larger than updrafts associated with surrounding boundary layer turbulence (~1–3 km wide). It is hypothesized that updrafts of this larger size are important for initiating cells to survive the destructive effects of buoyancy dilution via entrainment.},
doi = {10.1175/mwr-d-20-0391.1},
journal = {Monthly Weather Review},
number = 8,
volume = 149,
place = {United States},
year = {Sun Aug 01 00:00:00 EDT 2021},
month = {Sun Aug 01 00:00:00 EDT 2021}
}
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