GFS computer model - Tuesday
GFS computer model - Saturday
This week's hot forecast is in lock step with the calendar; the summer solstice arrives at 6:08 p.m. central time Wednesday. The day with the most daylight (14 hours and 37 minutes of it in Nashville) is also the day that the sun angle is highest.
What's really responsible for the abundance of 90s in this week's forecast, however, is a large high pressure ridge stretched across much of the southern United States.
The first image shows the mid-to-upper level pattern on Tuesday afternoon. I've drawn in the center of that high pressure ridge; which is really just a dome of hot, relatively humid, relatively storm-free air. Surface temperatures will be in the lower 90s here in Tennessee.
By the weekend, the center of that ridge of high pressure shifts westward toward the Central and Southern Plains. Here in the Mid-South, we'll still be close enough to the ridge that temperatures should reach the middle 90s then.
Records this time of year are generally around the 100° mark. While we won't break any records this week, we will stay 5° to 10° above average quite consistently.