Skilling: Cloudy, possible snow this weekend for Chicagoland

Friday’s seen the Chicago area visited by a PNEUMONIA FRONT—a southward moving front which shifts winds into the north/northeast down the length of Lake Michigan into Chicago.  

The north/northeast flow, with post frontal wind gusts topping 30 mph likely into Friday night, is carrying a shot of cold arctic air down the length of the lake—a set-up perfect for activating the lake -effect cloud & precip machine.

Temps peaked at 51-deg in Chicago but by late afternoon had crashed into the 30s. 

Clouds and precip with the PNEUMONIA FRONT are “post-frontal” in nature. In other words, THEY FOLLOW THE FRONT rather than occurring ahead of it. Weather radars had lit up with rain over the northern half of the metro area by mid Friday afternoon—but THE PRECIP WAS QUICKLY TRANSITIONIONG TO SNOW given the intensity of the chill riding into the area behind the front.

Full forecast details and more at the WGN Weather Center blog

Modeling takes precip over to snow and suggests a convective nature to the snow going into the evening. This suggests burst of heavy snowfall will occur over sections of the metro area in the evening and into Friday night—winding down late tonight, though clouds are to linger into morning.

The elevated snow intensity threatens some quick accumulations in the areas with the heaviest snowfall.  A quick inch or two accumulation wouldn’t be surprising in spots, particularly up and down the western shore of Lake Michigan in northeast Illinois—then into northwest Indiana—SO CARE SHOULD BE TAKEN DRIVING IN THE FAST CHANGING  ENVIRONMENT WHICH GREETS MOTORISTS IN THE EVENING COMMUTE PERIOD FRIDAY AND BEYOND.

Strong post-frontal wind gusts to 30 mph are likely, contributing to the rapid temp drop which will se 20s across the area for lows Friday night.

An overcast and even some flurries or snow showers may continue into Saturday morning. But the lake-effect cloud and precip set-up will break down with a windshift to the “SSW” later Saturday—and that windshift sets the stage for quite a temp rebound as Pacific air rushes back into the area Saturday night and Sunday.  It’s a warmer pattern which is to see temps resurge to within striking distance of 60 Sunday afternoon and into the mid 60s—which could break records Monday.  

By Tuesday, a late winter storm system will approach from the west sending unseasonably warm, moist Gulf air into the area and potentially setting the stage for the year’s first organized SEVERE WEATHER OUTBREAK later Tuesday into Tuesday night. 

Record level warmth is likely Monday with mid 60s likely—and unseasonable warmth likely to generate 2024’s first 70-deg temp Tuesday. 

Another SHARP BUT BRIEF COLD AIR INTRUSION sweeps in Wednesday and, like the cold surge coming tonight into Saturday, is to quickly yield to a new surge of mild air which will have Chicago area temps rebounding late next week with reading approaching if not resurging into the 60s next week.

The brief cold surges aren’t enough to interrupt the winter season’s warm trend. The meteorological winter season (the period since Dec 1) is now the warmest on record in Chicago with temps in that period running 6.3-deg above normal.

This week will post an 11-deg surplus—a surplus likely to be matched next week and the week which follows, despite the brief mid-week chill. Next week. The warmth’s appears likely to see the area heading into a wetter overall pattern.

HERE’S MY LATEST FRIDAY CHICAGO METRO FORECAST (2/23/2024)

…CAUTION FOR POTENTIAL SLIPPERY TRAVEL CONDITIONS DEVELOPING, ESPECIALLY ON LESS TRAVELED AND UNTREATED ROAD SURFACES THIS EVENING INTO FRIDAY NIGHT….

TONIGHT: Windy and colder with snowy spells this evening into Friday—winding down inland late but continuing sporadically in lakeside areas into Saturday morning.  Wind gusts to 30 mph. Low 27.

SATURDAY: Clouds, possible flurries or a few lake-effect snow showers lakeside counties into morning. Clouds break and mixed sun emerges in the afternoon. Chilly. High 40.

SATURDAY NIGHT: Scattered clouds, becoming breezy late. Low 34.

SUNDAY: Partly cloudy and much milder by afternoon. High 58.

MONDAY: Partly cloudy, windy and unseasonably mild. Possible record breaking warmth. High 67.

TUESDAY: Cloudy periods, breezy and abnormally warm for the season. Growing prospects for some afternoon showers and t-storms. Some active or possibly severe t-storms possible Tuesday night.  High Tuesday 71.

WEDNESDAY: Sharply colder and quite windy. Becoming partly sunny. Gusts topping 30 mph likely. High 37.

THURSDAY: Partly sunny, windy and noticeably milder. High 49.

FRIDAY: Mixed sun yields to clouds, windy and milder still. Showers possible in the afternoon and likely at night. High 55.

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