Temperatures stay above average, but it won't be the warmest Christmas

 
Even though temperatures may end up above average through the week of Christmas it won't be the warmest week as clouds, drizzle, light rain, and fog will likely persist through Christmas Day.

Temperatures Monday afternoon warmed into the upper 30s with Rockford's high reaching 38 degrees. As of 10pm, temperatures haven't really fallen much and remain in the mid and upper 30s. This can be attributed to a light breeze from the south and a warmer air mass moving in from the west. There is some clearing taking place, moving from west to east across northern Illinois. Temperatures won't fall too much with lows ending up in the low to mid 30s. There may even be some patchy fog that develops through Tuesday morning. Under partly sunny skies afternoon temperatures will climb into the low 40s.

High pressure from Tuesday will slide across the northern Great Lakes Tuesday night into Wednesday. This will turn winds to the southeast Wednesday afternoon keeping temperatures right around 40 degrees. Skies will remain mostly cloudy through mid-day Wednesday but an approaching upper-level disturbance and increase in moisture will allow some drizzle, and then light rain, to develop late in the afternoon and evening. Rainfall totals are not expected to be much and will only add up to a few hundredths of an inch.

Temperatures will remain mild through the night climbing only into the low 40s Christmas Day. The warm front that looked like it would cross the Stateline Thursday afternoon now appears to remain to our south, keeping northern Illinois and southern Wisconsin under an easterly wind. This will hold the cloud cover in place, along with any drizzle or fog that may occur from Wednesday night, as the warm front remains in downstate. Our warmest Christmas day occurred back in 2019 when the mercury climbed to 59 degrees. The average high temperature is 32. We won't be anywhere near the record, but our afternoon temperatures will be warmer than the average.

Light showers are likely to develop as both the warm front and surface low pressure system move in northern Illinois Thursday night. This will cause an area of showers to develop after 8pm or 9pm and lasting through Friday morning. All-in-all rainfall amounts between Wednesday and Thursday will remain under a quarter of an inch.