Precipitation falling from a cumulonimbus cloud in the form of pellets or balls of ice greater than 5mm in diameter. Hailstones are usually composed of concentric layers of clear ice and compact snow.
A narrative statement produced by the National Weather Service, frequently issued on a routine basis by a local weather forecast office (WFO), to provide information regarding the potential of significant weather expected during the next 1 to 5 days.
A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve. Helicity is proportional to the strength of the flow, the amount of vertical wind shear, and the amount of turning in the flow (vorticity). Atmospheric helicity is computed from the vertical [...]
Measure of the water vapor content of the air.
A tropical cyclone in the Atlantic, Caribbean Sea, Gulf of Mexico, or eastern Pacific, which the maximum 1-minute sustained surface wind is 64 knots (74 mph) or greater.