Highs Sunday were again in the low 90’s. While Des Moines missed a record high by one degree, this is the first time we’ve had three 90+ degree highs in a row in Des Moines this late in the year since 1897.

Changes are ahead as the heat will only last into Tuesday. The clouds and precipitation you see in the image above are associated with a trough of low pressure over the western United States. This will be moving in our direction this week.

The jetstream, a fast-moving river of air at the top of the troposphere, will be changing its configuration as we move toward the end of the work week. The aforementioned trough can be seen in the west in the image above from Sunday evening. The jetstream is shown by the wind arrows.

By early Thursday, the trough will move east and flatten. The warm air in place over Iowa to begin the week will be displaced to the southeast, opening the door for cooler air to pour in.

As the cooler air pushes in Wednesday, precipitation will form along the eastern edge of it ahead of a cold front. Rain chances look to begin in the late evening on Tuesday and last into Wednesday morning. Heavy rain and severe weather are not anticipated.

Behind the front, much cooler high temperatures will move in to our forecast.

Lows may dip into the 30’s in parts of Iowa Saturday morning. Temperatures look to rebound as we head into the following week.