You can breathe easy this weekend. Literally. A powerful cold front moved through the area Thursday, dropping temperatures into the 70s and dew points into the 50s, resulting in heat indices 20-30 degrees cooler than on Wednesday.
No high temperature records were set in Bemidji during the heat wave. In fact, Tuesday with its high of 91 was the only day to exceed 90. However, dew points in the 70s resulted in heat indices in the mid to upper 90s. The 10-day forecast calls for temperatures remaining around average for this time of year. Highs are predicted to be around 80 with lows bottoming out around 60.
So, what's the deal with the humid weather that overtook Minnesota this week? Turns out you weren't the only one sweating. Meteorologists have determined that large fields of corn raise the dew points in surrounding areas because corn "sweats" on hot days. When the humid air mass that originated over the Gulf of Mexico passed over the sea of green that is Iowa, sweating corn likely added to the humidity levels.
Another agricultural-related weather anomaly occurred Tuesday evening. Moorhead reported a heat index of 130 at 7 p.m. For that brief moment in time, Moorhead was the hottest place on earth. Both the dew point and heat index readings set records for the highest ever recorded in Minnesota.
The National Weather Service is saying those readings are the result of an "agricultural bias." The Moorhead weather station is surrounded by fields of sugar beets and soybeans - both transpiring plants, meaning they lose water vapor through evaporation. Combined with heavy rainfall earlier in the day which resulted in wet soil and standing water, the Moorhead readings represent a very localized condition and "did not represent the free atmosphere as a whole."
Tom Siemers is the Pioneer's circulation manager. Email him at email@example.com