Weather Word of the Day
October 26, 2020
Typically fog is composed of water droplets suspended in the air near the Earth's surface. When bitter cold temperatures are present, fog is composed of ice crystals instead of water droplets, and is called ice fog. Both types of fog reduce visibility at the surface.
October 25, 2020
Planetary Boundary Layer -
Also known as the Atmospheric Boundary Layer, it is the lowest part of the atmosphere and its behavior is directly influenced by its contact with the surface. The depth of the planetary boundary layer changes from day to night. During the day, the sun heats up the surface resulting in rising air currents that raise the height of the boundary layer. At night, the height of the boundary layer falls very close to the surface.
October 24, 2020
Centrifugal Force -
An apparent force that acts on an object moving in a curved path. Centrifugal force makes objects move outwards from their axis of rotation, making it appear that the object is being pulled outward. This force can be felt when taking a sharp turn in an automobile.
October 23, 2020
Ice Pellets -
Ice pellets are small, translucent balls of ice that are also known as sleet. Ice pellets form when falling snow encounters a region of above freezing air and melts or partially melts into raindrops and then refreezes as it encounters sub-freezing air near the surface. Ice pellets tend to bounce when they hit the ground.
October 22, 2020
Ground clutter -
Radar returns that are received from stationary ground-based targets. Most ground clutter is located 30 miles or less from the radar site, unless a temperature inversion is present. When a temperature inversion is present, the radar beam bends downward towards the earth's surface, creating ground clutter much farther away from the radar site. Common sources of ground clutter are hills, buildings, wind mills, and even wave crests at sea.
October 21, 2020
Crepuscular Rays -
The meteorological term used to describe rays of sunshine that poke through holes in the cloud cover. They oftentimes have a celestial quality to them.
October 20, 2020
The dissipation of a frontal zone due to a weakening contrast between two air masses. The temperature gradient weakens during frontolysis, meaning the rate of change of the temperature along the frontal boundary is lessening. At the end of frontolysis, the front no longer exists. The opposite of frontolysis is frontogenesis.