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 RateHeat Stress Category <= 90 breaths per minuteNormal 91 – 110 breaths per minuteAlert breaths per minuteDanger > 130 breaths per minuteEmergency

July 20 – July 22

Observed Heat Stress 07/20/08

Observed Heat Stress 07/21/08

Observed Heat Stress 07/22/08

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 ForecastBreathing Rate Average Mean Absolute Error Day breaths / minute Day breaths / minute Day breaths / minute

July 25 – July 27

Observed Heat Stress 07/25/08

Observed Heat Stress 07/26/08

Observed Heat Stress 07/27/08

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 ForecastBreathing Rate Average Mean Absolute Error Day breaths / minute Day breaths / minute Day breaths / minute

July 31 – August 3

Observed Heat Stress 07/31/08

Observed Heat Stress 08/01/08

Observed Heat Stress 08/02/08

Observed Heat Stress 08/03/08

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 ForecastBreathing Rate Average Mean Absolute Error Day breaths / minute Day breaths / minute Day 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)) – 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

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