Example Surface 3 Hour Dew point Temperature and Wind Change
Positive dew point temperature change areas are contoured in solid yellow lines and indicate that the dew point temperature is rising in that region. Negative temperature change areas are contoured in dashed yellow lines and indicate that the dew point temperature is falling in that region. Both dew point temperature change areas are contoured in intervals of 5 degrees Fahrenheit. Therefore, a positive dew point temperature change contour of 5 would indicate that the dew point temperature has risen by 5 degrees Fahrenheit in the past 3 hours within that contour.
The 3 hour wind change is represented by wind vectors in units of meters per second, as indicated by the length of each wind vector. The wind vectors also show the change in wind direction during the past 3 hours, as indicated by the direction the arrow is pointing. The length and magnitude of the strongest wind vector is shown in the lower right-hand corner.
The example image above shows an area of strong dew point temperature decrease and an increase in the westerly winds located near Wisconsin and Illinois. Both of these features are signs that a cold front has passed through that area.