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

July 20 – July 22

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