The west-east upper-level jet stream flow has surged far to the north over central Canada, allowing warm air over the western U.S. to build into the central Plains and mild air to reside over most of the rest of the country. In the Chicago area, a stationary high pressure is centered to our east and south, with the subsequent southerly flow allowing a slow warm-up the remainder of the week.
Tuesday was the second straight day with 100 percent sunshine, and expected abundant sunshine Wednesday may make it three in a row. Overnight temperatures have been low because of the dryness (dew points in the 40s) of the air mass, but as the air slowly modifies in place, each day’s nighttime temperatures seem to climb two or three degrees above the previous night’s — for example, lowest area temperatures Monday morning were in the upper 30s, Tuesday morning in the lower 40s, and Wednesday morning should be in the mid to upper 40s. Daytime highs are similarly on the rise, with near 80-degree highs possible with the approach of the weekend
