February, 2023 closes at midnight—bringing to an end what has been an unusually warm and snowless winter overall. Even with two arctic outbreaks—one in December; a second in January—the 3-month Dec through Feb meteorological winter season ends among the warmest 9% of the past 153 years in Chicago.

70% of winter days have been ABOVE NORMAL and the 3 month period closes having averaged 3.5-deg ABOVE NORMAL. We’ve found, as we mentioned entering the winter season, that LaNina winter in Chicago have biased ABOVE NORMAL with their temps in La Ninas since 1950 here.

Snowfall for the full season to date is just 57% normal—down more than 13″ from normal. The seasonal today currently on the books is 17.9″ versus the normal of 31.3″ by now.

METEOROLOGICAL SPRING –the period from March through April and May—gets underway with March, 2023’s arrival at midnight. The spring season is a time of continued warming overall and of lengthening hours of daylight. Chicago average temps March are 41/26—and by the time meteorological spring closes May 31, they’ll have increased to 76/56.

And perhaps most pleasing of all, possible daylight will have increased another 3 hours and 48 minutes!

It will feel a bit like spring Wednesday with temps soaring to within striking distance of 60-deg. Yet a wintry storm us just over 2 days away—arriving in a colder weather regime Thursday night, Friday and into Friday night. A howling “NE” wind will put in an appearance as a new round of heavy precipitation moves in.

The storm responsible is the latest to dive south out of the Gulf of Alaska into California—which is being battered by new precip and wind.

The system will do what its recent predecessors have done—sweeping across the Rockies and into the Plains where it will turn northeast into the Midwest.

This storm has the potential of producing a band of heavy snow—and more severe weather in its warm sector.

The precise layout of the storm rain/snow demarcation line—critical, because it’s just north of that line that storm’s like this one, produce their heavy snow—and that demarcation is to lay out very close to Chicago.

Forecast of how much snow will fall and where will be refined—but Chicago is likely to get in on some of that wet, heavy snow—though it may start as rain or a wintry mix and transition to snow Friday as storm dynamics cool the atmosphere. That’s a complicated process best modeled by a blend of forecast models, including higher resolution short term models that don’t yet cover Chicago. THEY WILL in coming days. It’s premature to offer precise placement of the heaviest snow—though history in this social media age shows some will try. Studies have overwhelmingly shown it’s better to get closer to the storm’s arrival to get a truly accurate picture of how it’s snows will lay out. You know we’re monitoring this and will have more to say in the hours and days to come when a far more accurate picture where this complex storm system will drop is heaviest snow and rain.

We have days to quietly watch developments as this storm gets its act together heading into the Midwest.

Full forecast details at the WGN Weather Center

TUESDAY NIGHT: Cloudy, periods of rain develop and move across the area in the midnight to 5 am time frame. Mild for the season. Low 37.

WEDNESDAY: Becoming partly sunny. Turning breezy and unseasonably mild with some 30 mph wind gusts by afternoon. High 58.

WEDNESDAY NIGHT: Partly cloudy up to the arrival of an overcast toward morning. Winds shift north by morning. Low 34.

THURSDAY: Cloudy and colder. Strengthening east/northeast winds. High 41—but 30s lakeshore.

THURSDAY NIGHT & FRIDAY: Windy and colder. Rain or a wintry mix develop late Thursday night and Friday morning turning to snow during the day amid wind gusts topping 40 mph by afternoon. Monitor forecasts. Accumulation of wet snow is likely of at least a portion of the metro area. Low Thursday night 34. Highs Friday 37—but falling back to freezing as the day proceeds.

FRIDAY NIGHT: Snow tapering off, windy and colder. Low 28.

SATURDAY: Partial clearing, initially windy but with velocities coming down. Chilly. High 41.

SUNDAY: Generous sunshine but with an increase in clouds late in the day and at night. High 44.

MONDAY: Cloudy and windy. Chance of rain. High 48.

TUESDAY: Mostly cloudy and windy. High 45—but 30s lakeshore.