FIRST THE MONDAY WEATHER HEADLINES

—RAIN’S ON THE WAY TO CHICAGO commencing, just after midnight in the city (a bit earlier west of Chicago) and continuing in early Tuesday morning—then winding down to a few spotty showers or sprinkles Tuesday. A cold front brings some re-energized showers mid and late afternoon Tuesday. 

—Included may be spotty thunderstorms tonight—then again mid and late Tuesday afternoon. Thunder is hardly a regular December/January/February occurrence here with the two months averaging fewer than one thunderstorm. 

—Model rainfall projections put most rainfall totals in the 0.4 to 1.10″ inch range through Tuesday—though with some convective rains possible in scat t-storms, a few heavier totals approaching 1.50″ are possible. 

—The coming week—the first full week of January 2023 is to average above normal and come in more than 3-deg warmer than last week and 4-deg above normal—this despite the fact daytime highs will fall back to the 30s from Thursday forward and some Wed/Thu snow showers and possible and another spell of snow can’t be ruled out in the Fri night/Saturday time frame. 

—January is typically Chicago’s coldest month with daily temp extremes of 33/21 Jan 1, 31/19 Jan 15 and 32/18 Jan 31. 

–Days lengthen slowly—but at an increasing rate in January. Chicagoans see daylight increase by about a half minute a day at the beginning of the month; a rate which increases to over 2 minutes per day by month’s end. 

–January sees daylight increase by 48 minutes in Chicago. But the month has played host to some big snowstorms historically—among them the infamous blizzard of 1968 and the Jane Byrne/Michael Bilandic blizzard of 1978. If there’s a big snowstorm in our future, it’s NOT showing up yet on models. Doesn’t mean one won’t happen, it simply means modeling hasn’t picked up on it yet. We will watch a weather system in the Fri night/Saturday time frame this week for SOME possible snow. Though there are NO current indications of major snow, some snow accumulation is at least a modest possibility.  

—Interestingly, Chicago and the Midwest are to continue in an ABOVE NORMAL TEMP REGIME over the coming 2 weeks (that’s through mid-month). 

–Winter weather enthusiasts may be heartened by indications of a colder, more typical winter weather regime with the potential for more frequent below normal temps later this month of some of our longer range models. I’ll keep you posted. 

–COUPLE OF SIDEBAR NOTES: 

—Despite the Christmas week cold spell which made such news, temps since the beginning of the meteorological fall season (Sept 1) have averaged more ABOVE NORMAL than not—with 72 days of that period (58% of them) finishing with ABOVE NORMAL AVERAGE TEMPS and only 52 days of that 124 day total (42% of them) BELOW NORMAL. 

–Another note–the New Year (2023) dawned with NO snow cover. Frank Wachowski checked for me and indicates 52 of the 138 years for which we have snow cover data in Chicago—that’s 38% of them—have begun without a cover of snow. We had an inch of snow on the ground last January 1—but the last time we had 3″ of snow on the ground on Jan. 1 was 2014 and the last time we had 4″ on the ground as a new year got underway was in 2008. Frank notes the last really significant Jan 1 snow cover was the 17″ measured 22 years ago in 2001. 

–Also of interest—and, I suspect, NOT SURPRISING to most folks here—is that 6 of the past 9 days have hosted less than 50% of their normal sun—-3 of those 9 days produced NO sun at all. And December 2022 finished with only 30% of its possible sun—only 75% of the paltry 40% of possible December sunlight considered “normal”. 

HERE’S OUR LATEST MONDAY CHICAGO METRO FORECAST (1/2/2023): 

TONIGHT: Cloudy, hazy and mild with rain developing and possible scat t-storms after midnight in the city—a bit sooner in the west and southern suburbs. Haze and areas of fog with temps steady or rising slowly—ending up in the low 40s many sections away from the lake by morning. 

TUESDAY: Mild for the season. Early rain gives way to less numerous sprinkles or light showers with some rain-free periods though clouds dominate. A NEW ROUND of showers and possible t-storms develops for several hours mid and late afternoon.  

High 51.  

TUESDAY NIGHT: A few breaks in the clouds, a little colder. A few sprinkles are possible at times—particularly late. Low 35. 

WEDNESDAY: More cloudy than not, strengthening winds and colder. Some passing daytime snow flurries are possible—building to snow showers Wednesday night. High Wednesday 43—but falling to the 30s. 

THURSDAY: Snow showers, breezy and colder. High 35. 

FRIDAY: Cloudy spells and chilly—though still above normal for the season. High 34. 

SATURDAY: Snow is possible, cold and breezy. High 34. 

SUNDAY: Possible lake effect flurries in the morning turning partly sunny by afternoon. Cold. High 34. 

MONDAY: Mixed sunshine—but clouds return by nightfall. Similar daytime highs. High 35.