|GOES-R IFR Probabilties over Wisconsin, computed from GOES-East (Upper left), GOES-East brightness temperature difference (10.7 µm – 3.9 µm) (Upper right), GOES-East Visible imagery (0.62 µm) (Lower left), GOES-R Cloud thickness (Lower right)
Stratus and fog look very similar from the satellite’s perspective, both during the day and at night. That is why it is important to include surface information in a product that detects fog and low stratus. The IFR Probability product over stratus-bound Wisconsin at mid-day on November 30 2012 shows a diagonal stripe of higher probabilities from southwestern Wisconsin to north-central Wisconsin. Airports that are reporting IFR or near-IFR conditions are located within this stripe. Over the rest of the state, where IFR probabilities are lower, the large majority of airports are reporting visibilities and ceilings exceeding IFR limitations. The character of the visibile satellite data, and of the brightness temperature difference product, gives very little indication that surface visibilities are reduced primarily from northeast Iowa/southwest Wisconsin to north-central Wisconsin.