Many locations in central and eastern North Dakota had thunderstorms move through in the past 24 hours. That precipitation was associated with a low pressure center with an attached cold front. Behind that cold front will indeed be some cooler air beginning today and lasting through the weekend. It will be southwestern North Dakota that will probably be one exception to that rule as warmer air will move into that area on Sunday, a full day before the rest of the state.
Maximum temperatures are expected to be in the 70s to around 80° from today (Thursday) through the weekend for a high percentage of the region. Then a return to above average temperatures is projected for the early to middle part of next week. In many ways, a very similar pattern to what we experienced over the past week. I do believe beyond this seven day period will be another shot of cooler air, followed once again by a surge of warmer temperatures toward the middle of August. That middle of August period of warmer temperatures may stick around for a longer period of time than what has occurred with other warmer periods this summer.
Additional rainfall looks to be scarce today through the weekend. At the moment, outside the isolated storm or shower that may pop up, the next chance of a more widespread rain event looks to be holding off until early next week. With a lack of rainfall in association with cooler air from Canada dominating our weather for the next several days, that drier flow from our northwest will limit the number of hours with high relative humidity (RH) until next week. Plus, with the next wave of warmer and more humid air expected to be brief when it does arrive, the overall number of hours of high RH even beyond this seven day outlook appears to stay on the low end of average for this time of year.
The projected growing degree days (GDDs) for base temperatures of 32°, 44° and 50° are presented in Figure 1. The estimated hours with RH above 85% is presented in Figure 2.