Skilling: Cloudy, possible wet Thursday for Chicagoland
when both the temperature and wind chill are taken into account—A BIG CHANGE!
Wednesday’s temp recovery included an end 65 consecutive sub-freezing hours which began at 6pm Sunday, ran through Monday and Tuesday, and finally ended when the city’s official O’Hare temp surged above freezing late Wed morning.
Temps rose slowly last night, moving from 19-deg at 11pm Tuesday night to 28 by 8am this morning as the milder air filtered in to the Chicago area—and by mid afternoon had reached 40-deg at O’Hare. It wouldn’t be surprising to see the day’s maximum reading top out at 41 before sunset brings on a nocturnal cooling.
Dominance of Chicago’s weather pattern shifted Wednesday from arctic-origin air to MILDER Pacific air Wednesday as a result in a shift in upper steering winds at the jet stream level. For several days, those important, weather-guiding winds blew into the Midwest from the northernmost reaches of North America. With the shift in those winds, air with an oceanic origins took over.
Pacific air is by its nature dry. Dry air warms nicely by day—but also cools at night.
A more active weather pattern seems to be coming together over coming days and the next week. The first of a series of weather systems likely to bring Chicago precipitation is slated in here early Friday. The form that precip takes will be interesting to monitor. It seems quite likely it will take the form of rain in the city—especially lakeside areas when “NE” winds will blow off the 45-deg waters of southern Lake Michigan. But air chilly enough to support a period of snow or a wintry mix isn’t to be all that far away Friday and we continue to see model indications snow or a wintry mix could occur in areas west of Chicago—but with some wet snowflakes possibly mixed in over parts of the city away from the lake and, with greater probability of occurring—over northern suburbs.
The first system moves on during Saturday so precip will break then. But additional systems follow—difficult to time with great precision and not being especially well handled yet by our models. One disturbance appears likely to swing through Sunday—another in the Tue/Tue night time frame. Both are come through with the demarcation between some rain or snow not solid at this point. They’ll have to be watched. Neither appears as a huge storm at this point.
Still another appears a possibility the following weekend and early week—with a spell of milder Pacific air between in the Wed/Thu/Fri/Sat period when daytime highs are likely to surge into the low or mid 40s—ABOVE NORMAL for this time of year. There’s a modestly colder look to the week which follows on current numerical forecast guidance.
December, which opens the 3-month meteorological winter period, arrives Friday. As noted here yesterday, December has historically been Chicago’s 3rd coldest month of the year—-January ranking #1 for cold and February #2.
HERE’(11/29/2023)
: Partly cloudy, not as cold. Southwest winds blow through the night. Low 29.
: Partly cloudy, windy and noticeably milder. High 51—Chicago’s first 50-deg or high temp in 10 day!
THURSDAY NIGHT: Clouds lower and thicken. Chance of rain toward morning—possible wet snow western sections toward the Fox Valley and northwest suburbs. Low 33.
: A chilly rain, possibly mixed with wet snow mainly west and north suburbs away from Lake Michigan. High 40.
: Extensive cloudiness lingers, seasonably chilly temps. High 42.
: Cloudy, chance of some rain or possible mixed wet snow. Breezy. High 42.
: Clouds may break at times allowing periods of mixed sun. Temps remain comparable to those of recent days—-a seasonably cool levels. High 42.
: Cloudy, chance of some rain or snow. High 39.
: Mostly cloudy, daytime temps continue at near seasonable levels. High 39.
