Validation of a Modified Fog Algorithm at WFO Miami using NASA SPoRT Satellite Imagery and Surface Observations

This study validates a new fog algorithm developed at the Miami Weather Forecast Office (WFO) based on a combination technique that uses the crossover temperature technique (Baker et al. 2002) in conjunction with a 15-knot wind maximum threshold at 925 mb. The fog algorithm is a modification of the United Parcel Service (UPS) Airlines technique based on crossover temperature and modified Richardson number (Baker et al. 2002). Prior to this study, the WFO Miami used a combination of factors to forecast fog, mainly moisture and wind speeds derived from forecast and observed soundings. However, a quantitative approach based on research results has not been used yet in South Florida. This study evaluates the results of the algorithm using the NASA Short-Term Prediction and Research Transition (SPoRT) Nighttime Microphysics image, GOES Spectral Difference (11µm minus 3.9 µm), and surface observations. The period of the study starts on November 2013 and it extends until April 2014. The comparison of the surface observations with the NASA SPoRT imagery will also increase the forecaster confidence using the NASA SPoRT imagery to detect fog in areas with no surface observations.