Final answer:
In the temperature section of a METAR, the air temperature is listed first and the letter 'M' indicates that the temperature is below zero Celsius. The dew point, which is significant in weather prediction, follows the air temperature.
Step-by-step explanation:
In a METAR report, the temperature section typically lists the air temperature first, followed by the dew point. The M prefix in values such as M05/M08 indicates that the temperatures are below zero Celsius. Thus, the correct answer to the question 'In the temperature section, what comes first, and when you have M05/M08 in the METAR, what does M mean?' is A) Dew Point; Below zero.
The dew point is crucial as it is the temperature at which water starts to condense out of the air. This plays a significant role in weather prediction and can also affect temperature changes. For instance, on nights when the dew point is below freezing, it indicates a potential for frost, which is of particular concern to farmers.
When discussing the importance of dew point, it's noteworthy that air temperature usually does not fall below the dew point because as soon as the air reaches this temperature, condensation occurs, releasing heat and thus preventing further temperature drops.