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Severe Thunderstorms and Heavy Rainfall in the Southern Plains; Heat Continues in the West

Strong to severe thunderstorms may bring areas of excessive rainfall and flooding over parts of the southern Plains today through Friday. Hot to dangerously hot temperatures are forecast across portions of the Pacific Northwest and southern Great Basin today. Gusty winds, dry, and hot conditions will bring critical fire weather to parts of central Washington state today. Read More >

With abundant fog around this winter, the Inland Northwest has seen its share of rime development. These photos, depicting quite large growth of the frost was taken outside our office during the third week of January.

Rime

By definition, rime is a deposit of interlocking ice crystals formed by direct sublimation on objects, usually those of small diameter freely exposed to the air, such as tree branches.

The deposition of rime is different than the process in which frost is formed. In the case of rime, the object and the air are both below freezing and liquid drops (e.g. fog) must be present. For frost, the object itself must be below freezing but the air can be above freezing. Also, water vapor (not droplets) are the source of moisture, so frost forms on clear cold nights.

Rime at NWS Spokane