1. A New Technique to Forecast Arizona Summer Thunderstorms Michael Leuthold Lecturer Department of Atmospheric Sciences University of Arizona

2. Arizona Summer Thunderstorms General Monsoon flow Thunderstorm formation over high terrain If conditions are right, storms can move into lower elevations of the state

3. Arizona Summer Thunderstorms Severe weather produced Damaging winds Dust Storms Lightning Flash Flooding

5. Current Forecast Methods Difficult to forecast summer thunderstorms because scale is small and lack of mid level forcing. NWS uses Persistence and Climatology in conjunction with other tools-models, weather balloon data, RADAR.

6. High Resolution Regional Weather Modeling Program Runs at high resolution, 5 to 10 times that of regular NWS weather models High res makes it possible to 'see' small scale features-mountains, valleys, cities, and their effect on local weather. High res also make it possible to 'see' small thunderstorms that eventually grow into big storms.

7. High Resolution Regional Weather Modeling Program Model has been 'tweaked' to better forecast weather over the deserts of the Southwestern US and Northwestern Mexico Model uses special moisture data to help better forecast storms as the accuracy of the forecast is very dependent on accurate moisture values.

8. A few examples of forecasts