Dew point and how it changes the intensity of heat in the summer

It has felt more comfortable outside over the past couple of days, and that is thanks to a cold front that recently moved through Missouri this Saturday. This cold front did a couple of things: first, it brought a cooler airmass from the north into the area, putting Missouri in northerly flow. Due to this northerly flow, it then brought drier air into the state. This led to relief from hot and humid conditions that were being caused by Missouri being stuck under southerly flow, which was pulling in moisture from the Gulf.

There are multiple ways to determine the moisture in a specific area, but one of the more commonly used methods is by measuring what is known as dew point. This is the hypothetical temperature that would need to be reached in order for the air to become fully saturated. The closest to saturation we can physically see is with fog, and this is caused why the air temperature and dew point are very close together or within a couple degrees of one another. This is most commonly seen in the morning due to overnight cooling leading to temperatures getting relatively close to the dew point before heating from the sun takes over, widening the gap.

Higher dew points are typically seen in warmer setups due to the increased amount of moisture the air can physically hold, while lower dew points will be seen in cooler setups. The level at which this dew point is measured will determine how "comfortable" or humid it feels outside. Dew points measured below 60 degrees will feel dry. If they are measured between 60 and 70s degrees, it will feel a bit more humid. If they are measured above 70 degrees, especially when paired with high temperatures, it will begin to feel tropical.

An example of higher dew point levels making it feel tropical or more uncomfortable was the extreme heat we experienced just over a week ago, August 15-17th. Dew points each afternoon were measured in the mid 70s, and air temperatures were measured in the mid to upper 90s at that point. The already intense heat combined with the higher moisture content in the atmosphere led to temperatures feeling like they were almost 110 degrees daily throughout this period.

Thanks to the cold front from this Saturday, it is a much different picture in central Missouri compared to just over a week ago. Dew points are expected to be in the upper 40s and low 50s Monday-Wednesday, which is well below average for this time of the year. Monday the 25th, the average is 64 degrees. Tuesday the 26th has an average of 66 degrees and Wednesday the 27th has an average of 67 degrees. The lowest dew points throughout this period have been measured in the upper 30s and mid 40s. Although the forecasted dew points aren't this low, it is still going to feel a lot less muggy and a lot more comfortable when it comes to spending time outside this week.