Some Snow Bookended By Bitter Cold
Snow Then Near Record Cold
The next eight days could collectively be worst of this winter in terms of bitter cold temperatures and snowfall. We have several chances for accumulating snow spread out between today and next Friday. Frigid air tonight has us flirting with record lows. Another round of possible record cold temperatures could arrive with Arctic air next weekend.
First things first. Snowfall today will be followed by dangerous cold tonight. A wind chill advisory is in effect from midnight tonight through noon Sunday. A winter weather advisory is in effect from noon today until midnight for the areas shaded in purple. Up to 4" of snow could fall between this afternoon and tonight and tomorrow morning's wind chills could dip down to -30°. Wind chills most of today will be sub-zero.
February is now running about a tenth of a degree below average. It now appears the month will end up below average overall based on the long term forecasts (more on that below). It would be the first to do so since October of last year.
Friday was the coldest day of the season so far. It was the only time we have seen highs in the teens so far this winter. Yesterday's high hit 19°. Today's highs should be a few degrees colder. Highs will range from high single digits well northwest of the city to the middle teens in the Loop.
Today won't hold the title of coldest day of the season too long. Sunday will be even colder with highs for the first time in a little over a year only reaching into the single digits.
The hourly forecast for O'Hare shows wind chills below zero for most of today and all of Sunday.
The GFS model has consistently called for record breaking cold for Sunday morning. The record low for Sunday morning is -10°. That is a longstanding record that goes back 146 years. The model is again calling for extreme cold with lows between -15° to -24°. Most models are calling for a more moderate brand of bitter cold temperatures. My forecast is calling for lows tomorrow morning between -2° in the city to -15° well northwest. I think O'Hare's low will come close to the record of -10°.
Cold Keeps On Coming
The GFS model keeps the sub-zero lows coming for Monday morning. It has lows dropping to -6° to -9°.
Another round of Arctic air could arrive next weekend. The long range models are hinting that it could be even worse than this weekend's. The GFS model has lows next Saturday morning dropping to -19° to -24°. Stay tuned.
The GFS temperature anomaly forecast shows just how widespread this next wintry blast of bitter cold will be. The Arctic air sweeps south through Texas and all of the Gulf Coast states.
The Chicago area would be around 40° below average for the middle of February.
Several Shots At Snow
The GFS model is still spitting out several rounds of mostly light snow starting today and continuing through the end of next week. The biggest snow could potentially come next Friday. Early estimates suggest at least 5" to 6" of snow.
The accumulated snowfall meteogram shows the range of snowfall predictions from several models. It shows a few inches with today's system and the system scheduled for late Monday. Most of today's snow will fall between the middle of the afternoon through about midnight.
The biggest amounts of snow are reserved for the third of three systems that arrives late Thursday into Friday. One model pushes the snowfall with that system to nearly 8".
The GFS model below suggest about a half inch to nearly an inch of snow with today & tonight's system. Keep in mind that this assumes a snow to liquid ratio of 10 to 1. That would be a heavy, wet snow. Our snowfall today with this bitter cold will be a lot fluffier. The snow to liquid ratio will be closer to 20 to 1 which would effectively double the snowfall numbers. That is why I expect snowfall more on the order of one inch to four inches with the heavier amounts south of the city.
The next round of snow picked up by the GFS model would be coming late Monday into Tuesday. The model is squeezing out another inch or two of snow with this system.
Cold Pattern To Persist
The colder pattern in the longer range forecasts spare very few parts of our country. It appears it may persist right through at least the middle of the month. The latest 6-10 day temperature probability forecast has the Chicago area outlooked for below average temperatures overall from February 11th through February 15th. The darkest blues, or highest probabilities for colder than average temperatures, remains centered over the middle part of the country. The longer range 8-14 day forecast continues to keep us outlooked for below average temperatures overall from February 13th through February 19th. There could be a few days were temperatures get to around or even above average but the overall trend is for a much colder pattern than what we have seen so far this winter.
The even longer range Subseasonal Experiment (SubX) forecast seems to suggest February will stay frigid (overall) through nearly the end of the month. The forecasts for both the week ending February 19th and the week ending February 26th have us favored for below average temperatures overall.
Quiet Longer Range Pattern
After several shots at snow the next few days the pattern may turn a bit more quiet for the middle of the month. The 6-10 day forecast favors us for below average precipitation overall from February 11th through February 15th. The 8-14 day forecast keeps us outlooked for below average precipitation overall from February 13th through February 19th.
Here is my 7 day forecast:
Today: Becoming mostly cloudy, light snow this afternoon & tonight High: 15
(A dusting to an inch of snow for northern suburbs in total with 2-3 inches in the city and up to 4 inches south of the city)
Sunday: Partly to mostly sunny Low: -9 High: 8
Monday: Mostly cloudy, light snow possible late Low: -2 High: 15
Tuesday: Partly to mostly sunny Low: -1 High: 13
Wednesday: Partly to mostly sunny Low: -2 High: 15
Thursday: Partly to mostly cloudy, light snow possible late Low: -2 High: 10
Friday: Snow possible Low: 9 High: 19