unstable the understanding severe thunderstorms and alberta boundary layers experiment neil taylor...
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UNSTABLEThe UNderstanding Severe Thunderstorms and Alberta
Boundary Layers Experiment
Neil Taylor1, Dave Sills2, John Hanesiak3, Jason Milbrandt4
1 Hydrometeorology and Arctic Lab, Environment Canada (EC)2 Cloud Physics and Severe Weather Research Section, EC
3 Centre for Earth Observation Science, University of Manitoba4 NWP Research Section, EC
Project Overview41st Annual CMOS Congress
St. John’s Newfoundland
April 18, 202341st CMOS Congress – St. John’s
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Outline
• Rationale
• UNSTABLE Goals and Science Questions
• Experimental Design
• Project Status
• Summary
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Rationale: Socio-economic Impacts
Alberta Foothills experience more lightning days than anywhere else on the Canadian Prairies
Burrows (2007, personal communication)
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Rationale: Socio-economic Impacts
Edmonton – Calgary corridor one of most densely populated regions in Canada and contains Canada’s 3rd (YYC) and 7th (YEG) busiest airports
Statistics Canada (2007)
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Rationale:Socio-economic Impacts
Edmonton – Calgary corridor among fastest growing regions in Canada
Statistics Canada (2007)
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Rationale:Socio-economic Impacts
• Frequent (Severe) Thunderstorms + People + More People + Busy Airports = Potential Human and Economic Loss
• Since 1980 > $2B and > 40 lives lost in AB due to severe thunderstorms
• Improved understanding of processes leading to severe storms better warnings mitigate impacts of severe weather on Canadians
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Rationale: AB Severe Wx Forecast Challenges
Forecasters face uncertainty with respect to:• ABL structure and evolution (especially vertical
water vapour profiles in ABL)• Role and importance of mesoscale boundaries /
circulations in foothills (dryline?)• Land surface – ABL interactions (sensible / latent
heat fluxes) in foothills and upstream• Conceptual models for CICompounded by:• Inadequate observation network to resolve the
above• NWP performance with respect to above
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• Large void of real-time surface observations over the Alberta foothills
• Foothills a known genesis region for severe thunderstorms
Rationale:Obs. Network
Hourly SFC observations available to PASPC
forecasters
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UNSTABLE Goals
• To improve understanding of atmospheric processes (especially in ABL) prior to and during CI and severe thunderstorm development
• To improve accuracy and lead time for severe thunderstorm watches and warnings
• To assess utility of GEM-LAM-2.5 to resolve physical processes over AB Foothills and ability to provide useful guidance for CI and severe thunderstorm forecasts
• To refine existing conceptual models describing CI and severe thunderstorm development over AB and the Western Prairies
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UNSTABLE Science Questions
ABL Processes (Taylor/Sills – Environment Canada [EC])1. What are the contributions of ABL processes to the initiation of deep
moist convection and the development of severe thunderstorms in the Alberta Foothills?
– ABL moisture, convergence boundaries and associated circulations
Land Surface – ABL Interactions (Hanesiak – U of Manitoba)2. What are the contributions of surface processes to the initiation of
deep moist convection and the development of severe thunderstorms in the Alberta Foothills?
– Soil moisture and mesoscale circulations, heat fluxes
Numerical Weather Prediction (Milbrandt – EC)3. To what extent can high-resolution NWP models contribute to
forecasting the initiation and development of severe thunderstorms originating in the Alberta Foothills?
April 18, 202341st CMOS Congress – St. John’s
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What is Needed to Resolve ABL and Other Processes Related to CI?
Mobile SFC
Mobile SFC
AircraftSoundingsProfilersTethersonde
Fixed Mesonet
N
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TargetedInstrumentation
Fixed• Mesonet stations (10-20)• 2 radiosondes• Tethersonde• 2 WV radiometers• Profiling radiometer (H2O profile)• GPS PW sensors• Eddy Correlation Flux Tower(s)?• Additional Profiling Radiometer (T, RH)?
Mobile• AMMOS / Strong Mobile (T, P, RH)• MARS (PW, SFC wx, profile – wind, T,
RH) • 3 radiosondes• Aircraft• Photography
Locations of fixed radiometers, GPS sensors, tethersonde to be determined
15 Station Configuration19 Station Configuration
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Experimental Design: Duration and IOP
UNSTABLE Study Period• 1 June to 31 August 2008• Fixed mesonet stations to be deployed prior to
June 1st 2008• Mobile instrumentation / communications tests in
15 June to 31 June window
Intensive Observation Period• Tentatively 9 July to 31 July (23 days) contingent
on field participation, expendables,…
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UNSTABLE Project Status
• Test of mesonet instrumentation summer 2006• Preliminary mesonet site selections last fall – further scouting
this summer / fall• Stockpiling radiosondes (currently 273)• Science questions and plan drafted• External UNSTABLE website at:http://www.umanitoba.ca/faculties/environment/envirogeog/weather/unstable/• First UNSTABLE science workshop held 18-19 April in
Edmonton• Science Plan being finalized and submitted for internal and
external funding• Mesonet instrumentation currently being deployed for BAQS-Met
in Southern Ontario• UNSTABLE Field Operations Plan to be drafted Fall/Winter
2007-08 with workshop to follow
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Collaborators
UNSTABLE is a collaborative project with National and Provincial
Government, Canadian University, and Private Sector participation
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Summary
• Potential for future human and economic loss in Alberta due summer severe storms is increasing
• Accuracy and lead-time of convective watches and warnings need to be maximized to mitigate impacts of summer severe weather
• Field experiment being designed to investigate ABL processes significant for CI and severe storm development over the Alberta foothills (summer 2008)
• Efforts to transfer results to SPC operations with aim to improve watches / warnings (e.g., RSD)
• UNSTABLE to include both observational and modeling components – targeted, high-resolution fixed and mobile surface and upper-air
observations – 2.5 km configuration of CMC GEM LAM
• Science questions and plan drafted – in process of refining science questions and instrumentation / measurement strategies
