Lake Effect Snow, what is it? The general public may not be familiar with this term, because this meteorological phenomenon does not occur in the Rocky Mountain region of the United States. However, lake effect snow is a common occurrence in the Great Lakes Region of the United States.
So what is lake effect snow anyway? In short, lake effect snow is produced from cold, dry air passing over warm waters, where snow falls on the lee side of the lake. Significant convective snow bands can be generated from this type of event and can lead towards extensive snow totals.
In Buffalo, NY, which lies on the east side of Lake Erie, has had lake effect snow events that occurred these past few days. Rochester, NY also has experienced lake effect snow since the city lies on the southern edge of Lake Ontario.
To monitor such events not only during the day, but especially during the night-time one can use polar-orbiting data. The Near-Constant Contrast (NCC), a derived product of the Day/Night Band (DNB), utilizes a sun/moon reflectance model that illuminates atmospheric features and clouds and senses emitted lights during the night-time hours. The NCC is a product which can help NWS forecasters assess the state of the atmosphere in complement with products that forecasters already have, such as infrared imagery (IR).
The NCC is shown in Figures 1 and 2 below, showing static images of western New York from 14-15 December 2016. The images highlight the emitted lights from the cities of Buffalo and Rochester along with the surrounding towns. The cloud cover and convective snow bands off of Lake Ontario and Lake Erie are apparent on 15 December 2016 at 0633Z (Figure 2). In the bottom left corner of both figures show the approximate moon percent visibility and the corresponding moon elevation angle presented in degrees above the horizon.
Figure 1: NCC image on 14 December 2016 at 0652Z, one can see the emitted light from the cities of Rochester and Buffalo, NY and neighboring towns. Lake Erie and Lake Ontario are shown as well. One can also see the high percentage of cloud cover over Western New York.
Figure 2: NCC image on 15 December 2016 at 0633Z, one can see the convective snow bands that were produced over Lake Erie and Lake Ontario as they head towards Western New York. The cloud cover is still persistent over the area as well.