Case Study Example 1

Evaluation for Calgary, Alberta for 21 January

In this report, Case Study Example 1, all temperatures are in degrees Celsius, and visibilities in kilometers. This report prepared by Certified Consulting Meteorologist (CCM) Dr. Mike Witiw. Using a Certified Consulting Meteorologist (CCM) will ensure the integrity of the report.


Throughout most of the day 21 January, light snow fell continuously through much of southern Alberta, southwest Saskatchewan and northern Montana. As the day progressed the snow area moved slowly southward, with snow ending in Calgary by 1400 Local Standard Time (LST). This snow occurred to the rear of a cold front which had passed through Calgary between 0300 and 0400 LST on 19 January. Prior to this event, over the period from 13 through 15 January, 3.4 centimeters of snow had fallen and was followed by a period of time where the temperature was above freezing for a part of each day.

Details of Calgary weather:

The following information is based upon certified copies of weather data provided by Environment Canada. Additionally, information on visibility and fog was obtained from Environment Canada’s climate website.

Earlier in the month, a total of 3.4 centimeters of snow had fallen on the 13th, 14th and 15th of January, 2003. On the 15th , a warming trend began with temperatures above freezing each afternoon, and going well below freezing at night. The temperature reached 8.70C during the early morning hours of January 19. At 0400 on 19 January, the temperature dropped to –2.00C and in the afternoon rose to a high of 2.2°C between 1200 and 1400 LST. At 1700 on 19 January, freezing fog was reported with a temperature of –4.2°C. At 2000 LST, visibility had decreased to .2 km. Snow grains were reported at 2000 LST. Between 2100 LST on 19 January, and 0400 LST on 20 January, freezing drizzle and freezing fog were both reported. From 0200 LST to 0400 LST the freezing drizzle and fog were accompanied by snow grains. The temperature at 0400 LST was –11.6°C. Snow grains and fog were reported at 0500; and between 0600 and 0900, 20 January, snow and fog were reported. For the remainder of the day, visibility improved, snow continued to fall, and temperatures remained between –12.9°C and –16.7°C. Snow continued to fall on 21 January ending between 1300 and 1400 LST. It remained cloudy for the remainder of the day. Temperatures gradually fell throughout the day. At 0800 LST, the temperature was –19.0°C; at 1400 LST, -19.6°C and at 1500LST, -20.4°C.