– Routine forecasts issued before noon contain three forecast periods: Today (or this Afternoon), Tonight, and the Next Day. Routine forecasts issued after noon contain four forecast periods: Tonight, the Next Day, the Next Night, and the following Day.

– When the temperature at or near the surface is expected to be 32 or below, during the growing season. Adjectives, such as “killing,’ “severe,” or “hard,” are used when appropriate. A freeze may or may not be accompanied by the formation of frost.

The altitude in the atmosphere where the temperature equals 32F.

– Rain (drizzle) which freezes on contact to produce a coating of ice on the ground and other exposed surfaces.

– Frontal Passage

– The formation of thin ice crystals on the ground or other surfaces in the form of scales, needles, feathers, or fans. Frost develops under conditions similar to dew, except the temperatures are colder.

– System developed by Dr. Theodore Fujita to classify tornadoes based on wind damage. Scale is from F0 for weakest to F5 for strongest tornadoes.