Weather Glossary - F
A | B | C | D | E | F | G | H | I | J - K - L | M | N | O | P | Q - R | S | T | U - V | W - X - Y - Z
F Scale - see Fujita scale
Fahrenheit Scale - a temperature scale on which the boiling point of water is at 212 degrees above the zero of the scale and the freezing point of water is at 32 degrees above zero
Far Infrared - the region of the electromagnetic spectrum with wavelengths greater than infrared but shorter than microwaves; radiation between about 4 microns and 0.1 millimeters
Ferrel Cell - in the general circulation of the atmosphere, the name given to the middle latitude cell marked by sinking motion near 30 degrees and rising motion near 60 degrees latitude
Fine Line - see thin line
First Law of Thermodynamics - the law of physics that states that the heat absorbed by a system either raises the internal energy of the system or does work on the environment
Flanking Line - a line of cumulus or towering cumulus clouds connected to and extending outward from the most active part of a supercell, normally on the southwest side. The line normally has a stair-step appearance, with the tallest clouds closest to the main storm.
Flash Flood - a local flood of great volume and short duration generally resulting from heavy rainfall in the immediate vicinity
Flash Flood Guidance - forecast guidance specific to flash flooding
Flood - the condition that occurs when water rises and overflows the natural or artificial confines of a body of water on to normally dry land, or accumulates in low-lying areas
Fluid - matter which flows; a gas or a liquid
Flux - the amount of flow per unit time (i.e. energy flux or radiation flux)
Fog - a cloud with its base in direct contract with the ground
Force - mass times acceleration; the ability to change an object's state of rest or motion
Forecast - a statement predicting an event will occur
Forecast Guidance - computer-generated forecast materials used to assist the preparation of a forecast
Forward Flank Downdraft - the main region of downdraft in the forward, or leading, part of a supercell, where most of the heavy precipitation occurs
Freeze (verb) - to solidify as a result of removal of heat
Freeze (noun) - a condition which occurs over a widespread area when the surface air temperature remains below freezing long enough to damage certain agricultural crops
Freezing Drizzle - drizzle that falls as liquid water but freezes upon impact to form a coating of ice upon the ground and on exposed objects
Freezing Rain - rain that falls as liquid water but freezes upon impact to form a coating of ice upon the ground and on exposed objects
Frequency - the rate at which an event will reoccur; the reciprocal of the period. In radiation, the number of wave crests that pass by a point each second, described in hertz.
Friction - the mechanical resistive force of one object on another object's relative movement when in contact with the first object
Friction Layer - same as planetary boundary layer
Front - the boundary or transition zone between two dissimilar air masses
Frontal Inversion - a temperature inversion in the atmosphere resulting from the vertical boundary between two air masses along a sloping front
Frontal Passage - the movement of a front across an area; characterized by changes in temperature, and, generally in pressure, wind direction and speed, visibility, cloudiness and precipitation
Frost - the condition which exists ice is formed on the earth's surface when the temperature falls below freezing
Frostbite - the freezing or local effect of partial freezing of some part of the body
Fujita Scale - a scale for classifying tornadoes according to the damage they cause; the tornado's rotational wind speed is inferred from an analysis of the wind damage
F0 Weak 40 - 72 mph Light damage
F1 Weak 73 - 112 mph Moderate damage
F2 Strong 113 - 157 mph Considerable damage
F3 Strong 158 - 206 mph Severe damage
F4 Violent 207 - 260 mph Devastating damage
F5 Violent 261 - 318 mph Incredible damage
Funnel Cloud - a rotating cloud column or inverted cloud cone extending downward from a cloud base that is not in contact with the ground
A | B | C | D | E | F | G | H | I | J - K - L | M | N | O | P | Q - R | S | T | U - V | W - X - Y - Z
© Copyright 2010. Lee's Weather, All rights reserved