The weather term in our vocabulary lesson for today is "warm advection." That means that warmer air blows in to replace cooler air. And we will get big-time warm advection this week as a persistent plume of very warm, increasingly humid air flows from the muggy Gulf of Mexico straight northward and smack into Minnesota.
Here is the short version in case you are in a hurry this Tuesday morning:
The warmup will begin Tuesday with just a gentle nudge on the thermometer up to seasonable temperatures. Afternoon high temperatures should range from the low and mid-70s across northern Minnesota to the low 80s in the south.
The Twin Cities should have a high around 82, which is exactly average for this date. Dew points will remain mainly in the 50s to continue the comfortable humidity.
A few showers in the northwest corner early will expand into scattered showers and thunderstorms as they cross about the northern third of the state during the daylight hours.
Some storms could become strong or severe in northern Minnesota Tuesday afternoon or evening. A marginal risk of severe weather (darker green color) has been posted by the Storm Prediction Center:
Temperatures will tick up a bit on Wednesday. Look for highs mainly from the upper 70s to mid-80s. The Twin Cities should top out around 85.
The heat and moisture plume will collide with a weather disturbance to provide the likelihood of thunderstorms on Thursday. Some storms might be rather strong.
High temperatures should rise mainly into the 80s.
Dew points are likely to push into the moist 60s for much of the state. Southernmost sections might get very sticky low 70s.
Heat wave by the weekend
A heat wave can be loosely defined as a period of abnormally and uncomfortably hot and humid weather, usually lasting two or more days. This coming period of Friday through the weekend should qualify for just about all of Minnesota except the Arrowhead.
Weekend high temperatures for most of Minnesota other than the cooler Arrowhead are likely to range mainly from the mid-80s to mid-90s. Dew points will climb well into the oppressive 70s both days. A few spots could see dew points touching 80 degrees, but the delayed growing season, which has resulted in less moisture transpiration from crops, might preclude such extreme moisture levels.
Of some concern in addition to the hot, steamy afternoons is that nighttime temperatures will not fall to seasonable levels. Weekend low temperatures, especially in the urban core of the Twin Cities area, might remain in the 70s. Houses and apartments do not cool well overnight under those conditions, which sets the stage for those dwellings to become even hotter during the ensuing day.
Air conditioning will be your friend. And a big pitcher of iced tea couldn't hurt.