Light Weekend Snow Then Bigger Storm
Arctic Air Moves Out
Our frigid Friday was the first day with below average temperatures in nearly a month. Before Friday we enjoyed a streak of 27 straight days with temperatures above average. Temperatures tumbled into the single digits this morning with wind chills dipping below zero. This was one of the coldest mornings of the season so far.
Highs today will climb into the upper 20s. This will probably be the coldest day we see for several days as we thaw out through early next week.
Two Main Shots At Snow
The complicated series of systems coming this weekend into early next week is becoming a little more clear. The first few systems this weekend will probably produce light snowfall. The bigger snow could come late Monday into Tuesday.
It certainly looks like we will put a dent in our snowfall deficit. So far this winter O'Hare has picked up 7.9" of snow. The average to date is around 15.7" so we are nearly 8" below average at this point.
The GFS model cloud cover and precipitation meteogram shows those two main periods of potential snowfall. These systems could contain a wintry mix at times. Light freezing drizzle is possible Sunday evening and night. There could also be some freezing rain or sleet with the second main push of snow late Monday into Tuesday. Most of the mix would probably be across our southern suburbs, probably south of I-80.
The accumulated snowfall meteogram for O'Hare considers not just the GFS model but many different computer models. It suggests our first round late Saturday into early Sunday could squeeze out anywhere from a dusting to 1.5". There could be some minor additional accumulation late Sunday into Sunday night too. The bigger snow would fall on late Monday and well into Tuesday. The model range is anywhere between just a few tenths of an inch to nearly a half a foot of new snow.
Models More In Alignment
The two main models that I will look at seem to be coming more into consensus. Still, the energy for the second possibly bigger snow system is out over the west coast. A lot could change between now and Monday. Just a slight shift in the track could mean the difference between a seeing a dusting of snow to getting dumped on with more than a half a foot.
Let's look at our weekend snowfall first. The GFS model forecast spits out about a half inch in total south and east of the city to 1.5" well north and west of Chicago. The city itself would get about a half of an inch to an inch. This is all the snow added up between late Saturday into Sunday and any additional snowfall Sunday night.
The European model spits out less snowfall for the first system. It suggests about a half inch for most areas with just a bit more well north and west of the city.
Who Gets Slammed By Snow Next Week?
The bigger snowfall amounts come with round two late Monday into Tuesday. The GFS model snowfall accumulation forecast adds up the weekend snow and any additional snow through Tuesday afternoon in the forecast below. It is showing grand totals approaching a foot north of the city with most areas getting seven to ten inches in total. Those totals include the lighter weekend snowfall too. This would be more of a heavier, wet type of snow. Snowfall amounts taper off quickly south of the city where there could be more of a mix of precipitation.
The European model has heavier amounts overall. It is showing grand totals (that include the lighter weekend snow) of around nine inches to just over a foot of snow. The heaviest swath of snow cuts right through the northern Illinois and the city of Chicago. This model brings the snow in a little later than the GFS model and has it linger a little longer into Tuesday.
Strong Signal For Mild Start To February
The long range temperature probability forecasts have increased the odd for a milder than average end to January and first part of February. The 6-10 day temperature probability forecast has the Chicago area outlooked for about average temperatures overall from January 28th through February 1st. The longer range 8-14 day forecast keeps us favored for above average temperatures overall for the period from January 30th through February 5th.
More Active Precip Pattern Developing
The long range precipitation probability forecasts hint at a return to near normal precipitation for the end of January and then flipping in early February to above average precipitation. The 6-10 day forecast favors us for about average precipitation overall from January 28th through February 1st. The 8-14 day forecast has us outlooked for above average precipitation overall from January 30th through February 5th.
The Climate Prediction Center has issued their revised forecast for February. It continues the same basic patterns that both the 6-10 day and 8-14 day outlooks suggest. We are outlooked for above average temperatures and precipitation overall for February.
Here is my 7 day forecast:
Today: Becoming mostly cloudy High: 29
Sunday: Light snow early, cloudy, light snow by evening Low: 25 High: 34
Monday: Light snow early but becoming heavier later in the day, blustery Low: 28 High: 35
Tuesday: Mostly cloudy, light snow possible Low: 28 High: 34
Wednesday: Partly to mostly cloudy Low: 24 High: 32
Thursday: Partly to mostly cloudy Low: 23 High: 33
Friday: Becoming cloudy, light snow develops late Low: 8 High: 28