Neil Taylor 1 , Dave Sills 2 , John Hanesiak 3 , Jason Milbrandt 4

1. 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 Manitoba 4 NWP Research Section, EC Project Overview 41st Annual CMOS Congress St. John’s Newfoundland

2. Outline • Rationale • UNSTABLE Goals and Science Questions • Experimental Design • Project Status • Summary 41st CMOS Congress – St. John’s

3. Alberta Foothills experience more lightning days than anywhere else on the Canadian Prairies Rationale: Socio-economic Impacts Burrows (2007, personal communication) 41st CMOS Congress – St. John’s

4. Edmonton – Calgary corridor one of most densely populated regions in Canada and contains Canada’s 3rd (YYC) and 7th (YEG) busiest airports Rationale: Socio-economic Impacts Statistics Canada (2007) 41st CMOS Congress – St. John’s

5. Edmonton – Calgary corridor among fastest growing regions in Canada Rationale:Socio-economic Impacts Statistics Canada (2007) 41st CMOS Congress – St. John’s

6. 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 41st CMOS Congress – St. John’s

7. 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 CI Compounded by: • Inadequate observation network to resolve the above • NWP performance with respect to above 41st CMOS Congress – St. John’s

8. Rationale:Obs. Network Hourly SFC observations available to PASPC forecasters • Large void of real-time surface observations over the Alberta foothills • Foothills a known genesis region for severe thunderstorms 41st CMOS Congress – St. John’s

9. 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 41st CMOS Congress – St. John’s

10. UNSTABLE Science Questions ABL Processes (Taylor/Sills – Environment Canada [EC]) • 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? 41st CMOS Congress – St. John’s

11. Aircraft Soundings Profilers Tethersonde Mobile SFC Fixed Mesonet Mobile SFC What is Needed to Resolve ABL and Other Processes Related to CI? N 41st CMOS Congress – St. John’s

12. 19 Station Configuration 15 Station Configuration 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 41st CMOS Congress – St. John’s

13. 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,… 41st CMOS Congress – St. John’s

14. 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 41st CMOS Congress – St. John’s

15. Collaborators UNSTABLE is a collaborative project with National and Provincial Government, Canadian University, and Private Sector participation 41st CMOS Congress – St. John’s

16. 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 41st CMOS Congress – St. John’s

17. Thank You! Neil.Taylor@ec.gc.ca (780) 951-8636 41st CMOS Congress – St. John’s