Cold Front Moving Through the Northeast U.S. Monday; Atmospheric River to Impact the Pacific Northwest Midweek

A cold front will cross the Great Lakes and Northeast U.S. through Monday with gusty winds and areas of rain showers. A strong atmospheric river is expected to move into the Pacific Northwest by midweek bringing a threat for moderate to heavy rainfall, gusty winds, and mountain snows for parts of Washington, Oregon, northern California, and the Sierra Nevada. Read More >

Florida Keys Cloud Chart

By Jim W. Lee

One of the many functions of the National Weather Service is to collect weather data and observations. One type of observation is a description of "sky condition", the amount and character of clouds visible in the sky. This is coded according to established categories, detailed on the three pages linked below.

Clouds need two major ingredients to form - rising air and moisture. These ingredients are usually only required at the altitude at which the clouds are forming or developing. For example, a cloud deck based at 10,000 feet above the ground indicates sufficient rising air and moisture at that level, but does not necessarily reflect the state of the atmosphere below 10,000 feet (or above the top of the cloud deck). On the following pages I will provide photographic examples and brief descriptions of the various cloud types that are identified for the purposes of sky condition observations. Low level clouds are generally based at or below 6,500 feet above ground, mid-level clouds are generally based between 6,500 feet and 15,000 feet above ground, and high level clouds are generally based more than 15,000 feet above ground.

All of the pictures on these pages were taken in the Lower Keys, unless otherwise noted.

On the following pages, click on any image for a larger version!

Low Clouds

Middle Clouds

High Clouds

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