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)

April 18, 202341st CMOS Congress – St. John’s

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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,…

April 18, 202341st CMOS Congress – St. John’s

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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

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Thank You!

Neil.Taylor@ec.gc.ca(780) 951-8636