Summerlike Humidity is Back.......For About a Day

Looks like humidity levels are going to increase rapidly today as lots of moisture works into the state. That will help spark showers and storms this afternoon in central South Dakota which will progress slowly to the east through out the day and night. These will likely be into the I-29 corridor in the overnight hours. With temperatures very mild today and an increase in moisture, it will likely get a bit muggy today. To measure the level of moisture in the air, we have the dew point. There are certain thresholds that we can use to determine the levels of humidity using the dew point. For example, a really muggy day vs. a very dry day. Well, below is a chart to explain the relationship between the dew point and when it feels humid outside.Now, I picked this particular image because it shows two different scales; one for people living out west that are not necessarily used to the high humidity, and one for people out east who live with it almost everyday of their lives. But this scale is completely relative and can be different for each person. But in the weather world, there are often too many variables to calculate so we typically just generalize everything. Well, since South Dakota is more of an in between state between the very dry rocky mountains and the very moist east coast, I would put the "South Dakota Dew Point Scale" somewhere in between the one that you see above. So I would say that less than 45 is very dry and then 46-50 is comfortable, etc.

The dew points as I'm writing this are steadily climbing, already into the upper 50's near the Missouri river as seen below.

And you can expect these to continue to climb through out the day. Notice that the forecast model below is saying dew points will be in the low to mid 60's for some of us by 4pm. And if you refer to the chart above, that would put us in the very humid category so drink lots of water if you are planning on being outside today.~KDLT Meteorologist Cody Matz