More Snow & Another Bitter Blast Of Arctic Air
Winter Settles In
It has been a remarkable turn of events. Winter shifted into high gear just a couple of weeks ago and has not let up since. After today we will have seen snowfall of at least a trace or more twelve of the past seventeen days. We have seen 23.9" of snow during that span of just over two weeks. That means we have seen 85% of an entire average winter's snowfall in under three weeks.
Lately it isn't just the snow that keeps coming but the cold keeps coming too. Today will be the sixth straight day with below average temperatures. It's the longest successive stretch of below average days this winter. February is now nearly 9° below average overall. The last month to come close to having temperatures that far below average was November of 2019 which ended up 5.5° below average.
Today's highs will be around 15° below average. Look for highs to reach into the middle to upper teens this afternoon. Average highs for today's date are around 34°.
More Arctic Air Sliding South
The GFS model brings in more bitter cold this weekend. The model forecasts a frigid Valentine's Day morning. A record that goes back 116 years could be in jeopardy. It drops the lows this Sunday morning down to -14° in northwest Indiana to -22° in our far northwestern suburbs. The record low for Sunday is -11° set back in 1905. The model has been bumping the temperatures up a bit in the past few runs so I expect these numbers to change for the warmer. Even with that in mind, it appears we could be in record cold territory this weekend.
The GFS model temperature anomaly forecast sweeps this next chunk of Arctic air southward through Texas early Sunday. The core of the cold air will be centered from near Chicago up through the northern plains where temperatures are forecast to be between 40° to nearly 50° below average.
Keep The Shovel Handy
The active snowfall pattern that began a few weeks ago shows signs of continuing well into next week according to the latest GFS model's meteogram. It has light snow falling today with another round later Thursday into Friday. More snow is scheduled for later Saturday into Sunday and then a prolonged period of light to moderate snow beginning Tuesday and lasting through nearly the end of next week.
The accumulated snowfall meteogram for O'Hare shows the range of snowfall predictions from several models. The first round today would amount to about a half inch of snow at the airport. The next round tomorrow would add another half inch to an inch of new snow. The weekend system could pile on anywhere between an inch to 3.5". The storm that starts next Tuesday could squeeze out anywhere between an inch to 6" of additional snow.
The GFS model total snowfall accumulation for today's system has very light snow north of the city and about a half inch to an inch for most areas. South of the city it lays down up to two inches of snow.
The GFS model total snowfall accumulation forecast through Tuesday has most areas picking up around three to four inches of snow in total but heavier snowfall in northern Indiana where lake effect snow is expected. This includes today's snowfall and everything else that falls through the start of next week.
I ran out GFS model total snowfall accumulation all the way through next Friday. These totals range from around 4" north and west of the city to around 10" in northern Indiana. It suggests a total of about 10" to 11" in the city. It includes all the snowfall possible between today and through the end of next week. The bottom line is several chances for accumulating snow over the next ten days with possibly the biggest accumulating snow coming toward the middle and end of next week.
Mostly Blue States
Most of the country is painted in blue for the longer range temperature probability forecasts. The darker the blue, the higher the probability of colder than average temperatures overall. The latest 6-10 day temperature probability forecast has the Chicago area outlooked for below average temperatures overall from February 15th through February 19th. The longer range 8-14 day forecast continues to keep us outlooked for below average temperatures overall from February 17th through February 23rd. In both cases we remain close to the darkest blue "bullseye".
The even longer range Subseasonal Experiment (SubX) forecast keeps this February frigid here through the end of the month and keeps the colder air coming into the start of March. The forecasts for both the week ending February 26th and the week ending March 5th have us favored for below average temperatures overall. The bullseye is again centered right over Chicago and the Midwest.
Favored For Above Average Precipitation
The probabilities are in the lowest range but still favor above average precipitation overall through nearly the end of the month. Based on the temperature probabilities forecasts discussed above, this precipitation would be snowfall. The 6-10 day forecast favors us for above average precipitation overall from February 15th through February 19th. The longer range 8-14 day forecast has us outlooked for around average precipitation overall from February 17th through February 23rd. The higher probabilities are in the southeast and northwest corners of the country.
Here is my 7 day forecast:
Today: Cloudy, light snow (more accumulation south) High: 18
(.5" to 1" for most areas but 2" or more along and south of I-80)
Thursday: Mostly cloudy, light snow mainly late Low: 3 High: 19
Friday: Mostly cloudy Low: 7 High: 18
Saturday: Cloudy, light snow Low: 5 High: 13
Sunday: Partly to mostly sunny Low: -5 High: 7
Monday: Partly to mostly sunny Low: -8 High: 12
Tuesday: Mostly cloudy, light snow possible late Low: 4 High: 21