Bath, Pa,

"N O T E" All weather articles written by the author, weather records for Bath, Pa. USA, graphs, graphics, pictures, are copyrighted and are owned by the author. If you make use of data from this site, please make reference to the: Station Licensee: Virginia T. Giannetta. Owner - Author: Charles A. Giannetta. Computer Consultant: Charles E. Giannetta & This Web Site. Thank you.

**Clouds & Weather Part I of II**

Any cloud from delicate wispy ice crystals six miles above the earth to a pea-soup London Fog, is a portion of air that has condensed into visibly moisture. Cooling of air to its dew point is the main reason for most cloud formation. The chief cause of cooling lies in some process which causes air to rise or to move upwards.

Large warm air masses may sometimes slide up the slope of a colder heavier mass of air.

Frontal Uplifting

As the warmer air overrides the cooler, the warm air expands and is cooling itself by the expansion of air molecules.

(Rising unsaturated air cools at approximately 5 Degs. F. per 1,000 feet, or 3 Degs. C. per 1,000 feet. This is know as the:

**Adiabatic Process**

As the warmer air rises and cools, it reaches the dew point, (the temperature at which condensation occurs), and cloudiness forms.

Air can also rise by being pushed up against mountains. This process is called:

**Orographic Lifting**

Forced aloft the rising air cools by expansion and clouds result as we often see along the Blue Mountains north of the Lehigh Valley. Another way air can rise is in vertical convection currents heated below by a warm surface, which is the first stage in the development of the thunderstorm. In all cases a cloud in the sky or fog on the ground is just a version of everyday forms of condensation.

**The Expelled breath smoke on a frosty morning or the steam from a teakettle are examples of condensation**

© 1998 Charles A. Giannetta

Clouds & Weather Continued Part II

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