WMOD00416

• Title: Wintertime Cloud Systems Over the Rockies: Three Case Studies
• Date: 12/1/1980
• Weather Modification - Doc Type: Report

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vertical. A comparison of the two radar sets revealed that, in general,

the K band radar was more sensitive and could detect smaller and fewer

ice crystals than the Ku band radar. Therefore, the K band radar ob-

served cloud top approximately 200 meters higher than the Ku band radar.

This is consistent with the wavelength differences between these two

radars. The reflectivity data, used in the first two case studies, was

taken from the Ku band digital data.

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1.5 Climatological Study of Steamboat Springs Precipitation

In order to place the following case studies in perspective with

respect to the precipitation that was produced by each different synop-

tic regime, a ten year climatological study was performed. Daily pre-

cipitation, accumulated from sunset to sunset during the winter months

November to April from 1970 to 1980 was recorded. Then a storm type

was assigned to each disturbance which produced a measurable amount of

precipitation, .01 inches at the precipitation gage located in Steamboat

Springs, Colorado.

The ten year study revealed that less than .1 inches of precipita-

tion fell on 37% of the days, on 64% of the days less than .2 inches

fell, on 80% of the days less than .3 inches fell, and on 97% of the

days .6 inches or less fell at Steamboat Springs. Storm types were

classified according to the movement of the vorticity maximums within

the 50 kPa (ki1opasca1s) synoptic waves. Table 1 illustrates various

characteristics of historical storms that were similar to those of each

case study.

Notice that none of these storm types were very frequent or pro-

duced the greatest percentage of the total precipitation with respect