Assessment / Application Exercises

Plot the following sets of data ("Group 1", "Group 2", and "Group 3") on separate graphs. Plot temperature and dewpoint on the same graph. You may plot RH separately or on a right axis of the temperature graph. Plot the wind gust (WMAX) on a separate graph. You don't have to connect your plotted symbols for the wind gust graphs. With your teacher's permission, you may use a computer to plot Group 3. Answer the following questions at the appropriate times:

After Plotting Group 1:

Like these observations, most weather observing stations traditionally have recorded their data once per hour. What time of day were these observations taken (during daylight or nighttime hours?). How do weather conditions normally change during this time of day? Do the observations in Group 1 fit with your expectations of how weather conditions typically behave?

After Plotting Group 2:

Describe the weather conditions observed at Fairview between 9:00 and 10:30 p.m. and compare with the conditions before and/or after this period. What were the maximum temperature, minimum humidity, and maximum wind speed values, and when did they occur? Compare this graph with your Group 1 graph.

After Plotting Group 3:

The phenomenon observed at Fairview is known as a heatburst. When thunderstorms weaken, they often eject strong downward gusts of wind, called downdrafts, beneath the thunderstorm. Usually, the downdraft contains moist air which evaporates beneath the thunderstorm and cools the downdraft, much like when moisture from your skin evaporates and makes you feel cooler. Sometimes, for reasons meteorologists don't understand, the downdraft contains dry air. When dry air descends, it compresses and warms rapidly.

Heatbursts were once thought to be rare events. From what you have seen in your plots, describe one reason why meteorologists would have thought they were rare. Also, in your answer, discuss which of these three groups of observations is adequate to observe heatbursts. Why do you think the word "burst" is used to describe this phenomenon?

Heatbursts are usually observed at night. Do you think it is possible for heatbursts to occur during daylight? If so, can you think of something that might prevent their observation during the day?

Station: FAIR -- Fairview, OK

Latitude: 36.2636 = 36 degrees 15 minutes 48 seconds North

Longitude: -98.4978 = 98 degrees 29 minutes 52 seconds West

TAIR: Air Temperature
TDEW: Dew Point Temperature
RH: Relative Humidity
WMAX: Wind Gust

Group 3 Data in Excel Format