These images represent the highest observed temperature which occurred during the past 24 hours between 7am CST (8am CDT) and 7pm CST (8pm CDT); as well as the lowest observed temperature between 7pm CST (8pm CDT) and 8am CST (9am CDT) For the official max and min temperatures at selected locations within the Grand Forks CWA refer to the Regional Temperature & Precipitation Table.
The images that are labeled Observed Maximum and Observed Minimum Temperature are locally generated from the Graphical Forecast Environment (GFE). This is a process used by the National Weather Service Offices nationwide to generate a variety of forecast, watch and warning products.Typically, the maximum daytime temperatures usually occur between 3 pm and 7 pm, while the minimum temperatures usually occur between 4 am and 9 am. These times vary depending on sky condition, wind direction and speed as well as a host of other factors.
For example, during the winter months across the northern plains it is not unusual to have the highest temperature of the day occur close to midnight, or in the pre-dawn hours. This can occur when a strong south wind brings warmer air into the region usually ahead of a cold front or storm system. This can cause temperatures to rise during the evening or overnight.
Conversely, minimum temperatures usually occur during the hours immediately before or after sunrise. In the winter this can be as late as 9 am, while in the summer it can be as early as 4 am. As with winter time maximum temperatures a strong frontal system can move through a region during the day causing falling temperatures through the afternoon and evening resulting in the minimum occuring much later than normal.