Despite a cold front moving through early Monday afternoon highs across the Stateline warmed into the mid and upper 80s, reaching 90 degrees in Rockford. Our high of 90 degrees broke the previous record high of 89 degrees set back in 1954, and was the warmest Rockford has been this late in the year since a high temperature of 90 degrees was recorded back on October 9th, 2010!
Blocking high pressure in the upper levels of the atmosphere, and persistent high pressure over the eastern Great Lakes at the surface will keep skies mostly clear and temperatures well above average. An ‘omega block’ in the jet stream – because it looks like the Greek letter omega – will focus the heat across the middle of the country, keeping high temperatures in the low to mid 80s through the end of the week. While close, it does appear that the record highs for Tuesday, Wednesday and Thursday should remain in place; record high for 9/28 – 91°, 1952 – 9/29 – 94°, 1953 – 9/30 – 92°, 1971.
The heat combined with the ongoing drought conditions across much of the country is just a recipe for the above average warmth to continue. While not as hot for Tuesday, the high temperature in Rockford is forecast to reach 84 degrees, then 87 degrees for both Wednesday and Thursday. By Friday the blocking ridge will begin to break down as a slight increase in moisture will be found as low pressure lifts north from the Southwest. High pressure to the east will keep the majority of the moisture west of the Stateline, however, with just a slight increase in cloud cover Thursday and Friday.