Assessment / Application Exercises

1. Below is the graph of temperature, dewpoint, and relative humidity for the previous day. Describe the differences in the two days. In particular, note when the times of greatest temperature increase occurred on each day.

The relative humidity is high (above 95%) between midnight and 7:00 a.m. Accordingly, the temperature and dewpoint values are close to each other over the same period. While some temperature increase is noted between 8:00 a.m. and noon (5 degrees in 4 hours), the greatest tempreature increase doesn't occur until after 12:00 noon (13 degrees in 4 hours). The maximum temperature is 10 degrees colder as well. On the 6th, the temperature rises 14 degrees between 6 and 10 a.m.

2. Now suppose that snow was observed at this station between midnight and 2:00 a.m and between 7:00 and 9:00 a.m. Are there any clues in this graph that might suggest the possibility of snow in the morning? What weather factor (clue: remember it snowed) may explain the difference in timing of the temperature increase on this day as compared to the 6th?

When the relative humidity is high before sunrise, the temperature is below freezing. This indicates the possibility of freezing precipitation, either freezing rain, sleet, or snow. Because there was precipitation, clouds may have obscured the sunlight until the afternoon hours, delaying the maximum heating and temperature increase until then.

Station: KINL -- International Falls, MN

Latitude: 48.5619 = 48 degrees 33 minutes 42 seconds North

Longitude: -93.3978 = 93 degrees 23 minutes 52 seconds West