Verification of USDA-MARC Heat Stress Forecasts
Preliminary Results
•Three Time Periods from 2008
•July 20 – July 22
•July 25 – July 27
•July 31 – August 3
•For this study a forecast breathing rate error of 20 breaths / minute or greater is considered excessive
Verification of USDA-MARC Heat Stress Forecasts
Preliminary Results
Predicted Breathing Rate Heat Stress Category
<= 90 breaths per minute Normal
91 – 110 breaths per minute Alert
111-130 breaths per minute Danger
> 130 breaths per minute Emergency
Observed Heat Stress07/20/08
Observed Heat Stress07/21/08
Observed Heat Stress07/22/08
07/18/08 Day 3 Heat Stress Forecast Error(forecast for 07/20/08)
07/19/08 Day 2 Heat Stress Forecast Error(forecast for 07/20/08)
07/20/08 Day 1 Heat Stress Forecast Error(forecast for 07/20/08)
07/19/08 Day 3 Heat Stress Forecast Error(forecast for 07/21/08)
07/20/08 Day 2 Heat Stress Forecast Error(forecast for 07/21/08)
07/21/08 Day 1 Heat Stress Forecast Error(forecast for 07/21/08)
07/20/08 Day 3 Heat Stress Forecast Error(forecast for 07/22/08)
07/21/08 Day 2 Heat Stress Forecast Error(forecast for 07/22/08)
07/22/08 Day 1 Heat Stress Forecast Error(forecast for 07/22/08)
07/20/08 – 07/22/08
Forecast Breathing RateAverage Mean Absolute Error
Day 3 17.287 breaths / minute
Day 2 14.674 breaths / minute
Day 1 12.865 breaths / minute
July 25 – July 27
Observed Heat Stress07/25/08
Observed Heat Stress07/26/08
Observed Heat Stress07/27/08
07/23/08 Day 3 Heat Stress Forecast Error(forecast for 07/25/08)
07/24/08 Day 2 Heat Stress Forecast Error(forecast for 07/25/08)
07/25/08 Day 1 Heat Stress Forecast Error(forecast for 07/25/08)
07/24/08 Day 3 Heat Stress Forecast Error(forecast for 07/26/08)
07/25/08 Day 2 Heat Stress Forecast Error(forecast for 07/26/08)
07/26/08 Day 1 Heat Stress Forecast Error(forecast for 07/26/08)
07/25/08 Day 3 Heat Stress Forecast Error(forecast for 07/27/08)
07/26/08 Day 2 Heat Stress Forecast Error(forecast for 07/27/08)
07/27/08 Day 1 Heat Stress Forecast Error(forecast for 07/27/08)
07/25/08 – 07/27/08
Forecast Breathing RateAverage Mean Absolute Error
Day 3 22.154 breaths / minute
Day 2 20.839 breaths / minute
Day 1 17.894 breaths / minute
July 31 – August 3
Observed Heat Stress07/31/08
Observed Heat Stress08/01/08
Observed Heat Stress08/02/08
Observed Heat Stress08/03/08
07/29/08 Day 3 Heat Stress Forecast Error(forecast for 07/31/08)
07/30/08 Day 2 Heat Stress Forecast Error(forecast for 07/31/08)
07/31/08 Day 1 Heat Stress Forecast Error(forecast for 07/31/08)
07/30/08 Day 3 Heat Stress Forecast Error(forecast for 08/01/08)
07/31/08 Day 2 Heat Stress Forecast Error(forecast for 08/01/08)
08/01/08 Day 1 Heat Stress Forecast Error(forecast for 08/01/08)
07/31/08 Day 3 Heat Stress Forecast Error(forecast for 08/02/08)
08/01/08 Day 2 Heat Stress Forecast Error(forecast for 08/02/08)
08/02/08 Day 1 Heat Stress Forecast Error(forecast for 08/02/08)
08/01/08 Day 3 Heat Stress Forecast Error(forecast for 08/03/08)
08/02/09 Day 2 Heat Stress Forecast Error(forecast for 08/03/08)
08/03/08 Day 1 Heat Stress Forecast Error(forecast for 08/03/08)
07/31/08 – 08/03/08
Forecast Breathing RateAverage Mean Absolute Error
Day 3 18.596 breaths / minute
Day 2 15.475 breaths / minute
Day 1 12.902 breaths / minute
•Breathing rate equation verified fairly well during these three time periods
•Day 2 and day 3 forecasts from 07/25 – 07/27 produced greatest forecast breathing rate error
Conclusions…
•Forecast temperature most responsible for error in forecast breathing rate
•Breathing Rate =(2.83 X Temperature) + (0.58 X Humidity) – (0.76 X Wind Speed) + (0.429 X (100 – Cloud Cover)) – 196.4
•Forecast relative humidity off by 8% - 12%
•We (NWS forecasters) could benefit heat stress forecasts greatly through improved relative humidity forecasts
Conclusions…
•Roger Eigenberg (USDA-MARC)
•Tami Brown-Brandl (USDA-MARC)
•Scott Opbroek (USDA-MARC)
•Randy Bradley (USDA-MARC)
•Rick Ewald (NWS)
•Aaron Johnson (NWS)
Thank You
Questions
http://www.ars.usda.gov