FLOOD01363

• County: Statewide
• Title: Colorado High Plains Thunderstorm Systems - A Descriptive Radar-Synoptic Climatology
• Date: 6/1/1974
• Prepared By: CSU
• Floodplain - Doc Type: Educational/Technical/Reference Information

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36

idea of a relationship of terrain slope variations and resulting

radiational differences between repeated occurrence of preferred pre-

cipitation paths is not new. Rhea (1968) did a study of summertime

convection in the mountains of northwestern Colorado which related the

repeated occurrence of preferred precipitation paths to upstream

terrain slope and orientation.

It would appear that the preferred convective genesis found over

hot spots requires a blend of proximity to .low level moisture sources

and the topographic characteristics which maximize convergence of this

moisture into the genesis zone to create the excessive number of

thunderstorms observed. The significance of hot spots' thunderstorm

production will be spotlighted in the next section.

Significance of Hot Spots

The magnitude of orographic hot spot influence on Colorado High

Plains convection is apparent when one considers the following:

1. Forty-one percent of all thunderstorm echo systems observed

in the network during 1970-1972 originated over hot spots

although they comprised only about 10 percent of the area

under study.

2. Over 50 percent of the thunderstorms \~hich formed over terrain

above 5000 feet elevation formed over hot spots which com-

prised just over 20 percent of the area.

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3. Mlen the data sample is area weighted, 6 times as many thunder-

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storms originated over hot spots as did over the plains.

4, Seventy-three percent of all thunderstorms that produced

severe weather on Colorado's High Plains during the SUIIUllerS of

1970 and 1971 originated over hot spots.