Valley fog filled Appalachian valleys on November 8, 2026

NASA said satellite imagery showed valley fog across part of the Appalachian Plateau on November 8, 2026. The MODIS instrument on NASA’s Terra satellite acquired an image that morning, while VIIRS on NOAA-21 acquired another image that afternoon.

According to NASA, low clouds appeared white as they filled many valleys in the natural-color image from MODIS. Autumn vegetation appeared in shades of brown and green. The VIIRS false-color image showed water in dark blue and vegetation in bright green after the clouds dissipated.

NASA said the clouds appeared to be fog, a type of cloud that forms near the ground. Foggy mornings in the region are common this time of year. Longer nights give the ground more time to radiate away the day’s heat, causing air above it to cool to the dew point.

According to NASA, water vapor begins condensing into tiny droplets when the air reaches the dew point and becomes saturated. Cold air is denser than warm air, so it flows downslope and pools in valleys, where fog tends to form first.

NASA said fog filled branching valleys across part of the Appalachian Plateau in eastern Kentucky and southwestern West Virginia. Rivers and streams along valley floors supplied extra moisture. The pattern was also visible along the Cumberland River and its reservoirs in north-central Tennessee and south-central Kentucky.

According to the National Weather Service, temperatures in many places on the morning of November 8 dipped into the 30s Fahrenheit before giving way to a mild, sunny afternoon. Forecasters reported locally dense valley fog, and earlier dense fog prompted advisories for hazardous travel conditions. NASA published the announcement Tuesday 10 November 2026.