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Severe Convective Storms An Overview

Severe Convective Storms An Overview. Part 2 – Rebecca Bethke. Severe Convective Storms An Overview. Doswell C.A. III, 2001: Severe Convective Storms – An Overview Severe Convective Storms, Meteor. Monogr., 28, no. 50, Amer. Meteor. Soc., 13-26. General Outline. Severe Convection

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Severe Convective Storms An Overview

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  1. Severe Convective StormsAn Overview Part 2 – Rebecca Bethke

  2. Severe Convective Storms An Overview • Doswell C.A. III, 2001: Severe Convective Storms – An Overview • Severe Convective Storms, Meteor. Monogr., 28, no. 50, Amer. Meteor. Soc., 13-26

  3. General Outline • Severe Convection - classification, problems, issues - distinction between non- and severe convection • Observations of Severe Convection - large-scale - mesoscale • Prediction of Severe Convection - current accuracy - goals for severe convective storm forecasting, to mitigate threats

  4. Severe ConvectionClassification and problems • >=3/4 in. hail • >=50 knot sustained wind gusts • Tornado • Should the average hail size and wind gust be reported as “severe” instead of the single largest size reported? • Precipitation not officially defined beyond severe • Flash floods and heavy rain consideration must include areas’ hydrological circumstances • Hales 2-tiered system for severe thresholds

  5. Observations of Severe ConvectionLarge-Scale • Rawinsonde observations are primary • PROBLEMS: - significant gaps worldwide - limiting analysis to the few “oubreak” events • Fig 10: Chart idealizing significant synoptic features in an outbreak of severe convective storms

  6. Observations of Severe Convection • Ingredients-based approach • conditional instability • moisture • a source of lift • V.S. Characteristic pattern alone

  7. Observations of Severe ConvectionMesoscale • Satellite images (qualitative) • Radar, limited • Important aspect: Convective Outflow • Processes • free “internal” instabilities • forced “external” processes • fronts • gravity waves

  8. Prediction of Severe Convection~Current accuracy levels • Progress • Advances in forecasting severe storms and tornadoes, SEE FIG. 12 • Increased prediction accuracy • Better public awareness and communication • Frustrations • Not as much attention to non tornadic events • Flash floods/heavy convection not offically “severe” • Hail formation and short-range forecasts

  9. Prediction of Severe Convection~Lessening the threats posed • Needed outside North America • systemic reporting • A way to including events in climatological database • sufficient planning for possible severe events in area’s where threat is rare • public awareness, appropriate reactions

  10. Prospects and Unsolved Problems • Forecasting • Improvements in observing systems (ie radar) and related forecasting systems • Difficulties/ less progress • Tornadic vs nontornadic supercell differentiation • Forecasting nonsupercell tornado situations • System to forecast and mitigate flash flood damage

  11. Prospects and Unsolved Problems • Weather Modification possibilities • Public appeal • Lack of many severe convective weather processes • New Observations • Doppler RADARs are likely only a beginning • Dual polarization observations possible • Satellite remote sensor improvements • Economic difficulties

  12. Severe ConvectionFinal thoughts • Mesoscale and smaller events • “Chaotic” systems • Important unobservables • Resources needed

  13. Severe Convective Storms This is the paradox of all science: we are both excited and frustrated by what we do not know, even as we create new understanding”. - Charles A Doswell III, May 2000

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