Tim’s Weather World: Brrrrreaking another record this winter?

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Today was the 20th day this winter that temperatures have dipped below zero at O’Hare.  Tomorrow should be the 21st. That is triple the average of 7 days per winter.  The record number of sub-zero days for a winter was 25 set back in 1884-1885.   The way this winter has been going that record is certainly within reach.  50 out of 72 days or 69% of days this winter have been below average.

Tim Special Cold Columns

February has started out frigid.  Here are some of the colder lows we saw this morning:

-26° Rochelle

-19° Aurora

-17° Sycamore

-16° Kankakee

-14° Streator

-14° Lowell

-12° Beecher

-13° Rockford

January will probably go down in the record books as the 8th coldest on record for the state of Illinois.  The average temperature statewide last month was 18.2° or 8.1° below average.



Tim’s Weather World: Let it snow, let it snow, let it snow

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If winter is going to be nasty, we might as well try to set some records…

So far this month we have seen 33.5″ of snow.  That is nearly an average winter’s snowfall in just 31 days.  This means January 2014 now ranks as the third snowiest on record.

Snowiest Januarys in Chicago:

1) 42.5″ January 1918

2) 40.4″ January 1979

3) 33.5″ January 2014

We could add another .5″ to 1″ by midnight but not enough to move beyond third place.

Here is how we compare to other cites for snowfall so far this snow season:

So far….                            January                                  Snowfall Season

O’Hare                                  33.5″                                         48.6″

Minneapolis                         22.7″                                         39.7″

Green Bay                           17.0″                                         44.6″

Bismarck                               5.8″                                         23.9″

Denver                                 14.0″                                         22.1″


Nearly half (49.4″) of the contiguous US is reporting snow cover with an average depth of 4.6“.  That is up just a bit from last year at this time when 44.6% of the country had snow cover.

Stay tuned…

Models are hinting at the possibility of another significant snowfall late Tuesday into Wednesday next wee.



Tim’s Weather World: Below average but not brutal

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Colder than average weather will continue for the next several days but we won’t break any records.  That is considered good news for a winter like this one that has been particularly cold.  2 out of every 3 days this winter have been below average.  Today will be the 9th day in a row below average.  We have dipped below zero 15 times this winter or nearly twice the long-term average.  So far this month the average temperature at Anchorage, Alaska (29.8°) is nearly double the average temperature at O’Hare (15.°2).

The 6 to 10 day forecast has outlooked us for a frigid start to February.  We won’t be alone in our shivering.  Only four states don’t have at least a portion of their state outlooked to be below average during the period of February 3-7.  The good news is that we don’t see any sub-zero lows through the weekend and into early next week.




Tim’s Weather World: Polar vortex visits again

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Just when we thought this winter couldn’t get any worse….

Bitter, dangerous cold has gripped the area today and will stick around through Wednesday morning.  Temperatures for some in the Chicago area may not climb above zero until midday Wednesday.  A wind chill warning continues until 9 AM Wednesday with wind chills as cold as -20° to -40°.  The coldest wind chills may occur early tomorrow morning (see image below). This cold outbreak will rival the outbreak that gripped the area three weeks ago.  Tonight’s lows will dip to close to -20° at O’Hare to break the old record low for Tuesday of -13° set back in 1977.


This winter has been especially brutal with both bitter cold and frequent snowfall.  We have seen at least one tenth of an inch of snow or more 27 of the past 50 days!  That means that nearly every other day we have seen measurable snow since early December.  Over four feet of snow has fallen this winter (48.2″).  33.1″ of that fell in January alone.  We have nearly seen an average snowfall for an entire winter (36.7″) in the month of January.

When it isn’t snowing it is bitterly cold.  This winter (as of yesterday) is the 13th coldest on record.  By Wednesday we will have seen subzero temperatures occur on 16 days so far this winter.  That nearly doubles the average number of days in Chicago at or below zero.  On average we record temperatures that cold 7 days each winter.



Tim’s Weather World: Snow & cold keep coming

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Our active winter weather pattern continues as if it is on steroids.  Wind chills tonight will dip down to 20-30 below zero.  Wind chills will remain subzero through Thursday with high temperatures in the single digits.  Bitter cold and strong winds will cause wind chills to plummet again down to 30 below or even colder late Thursday night and into early Friday morning.   The longer range forecast keeps us in the deep freeze through the end of January and hints at a frigid start to February.   Most of the eastern half of the country is outlooked for overall below average temperatures for that period.


There are three “opportunities” for sticking snow between today and Monday.  Today’s snow will be a quick coating of up to 1″.  Friday night into Saturday another system will slide across the area with the potential for 1-3″ of snow.  The wildcard is Sunday’s system.  Some models have it diving just south of Chicago and only scraping us with light snow while other models have a more direct hit with several inches possible.

The GFS accumulated snowfall forecast through Sunday brings a grand total of 3-6″ for all three systems combined.  We have already seen 44.8″ for the snowfall season to date.  That ties 1977-1978 for the third highest snowfall total on record through January 21st.  29.7″ of that fell in January alone making it the fourth snowiest January on record.

Snowfall accum

Stay tuned.



Tim’s Weather World: 2013 in review


NOAA has released their national overview for the year 2013.  While it was a warmer year relative to climate averages, it was quite a bit cooler than 2012.  The average temperature for the contiguous US last year was 52.4° or .3° above the 20th century average.  That makes 2013 the 37th warmest year in the 119-year period of record.  As warm as it was compared to average, 2013 was still 2.9° cooler than the 2012.


At the state level, Illinois had an average temperature of 50.8°.  That was quite a bit cooler than the statewide average of 55.6° in 2012.  Only four months (see image above) saw above average temperatures last year.


At the city level,  2013 was the 29th warmest for Chicago of the 55 years of record from the National Climatic Data Center (see image above) with 2012 still the warmest on record.  The average temperature last year was 49.3 ° or -.6° below the 1981-2000 average.



Tim’s Weather World: Breaking winter’s back for now

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What a difference a week makes!  Today’s highs in the 40s will be 50° warmer than last Monday.  While we do have a couple of colder days ahead this week, there is nothing all that frigid on forecast horizon compared to last week.  Friday’s high of 18° is the coldest day of the next seven.

Looking longer range the news gets even better.  The 6 to 10 day outlook has about 2/3′s of the country basking in above average temperatures for the middle of January (18th-22nd).  We could use the break from the bitter cold.  8 of the first 12 days of January have been below average and 28 of the first 43 days of winter have been below average.




Tim’s Weather World: Some snow stats before it melts away


The “polar vortex” and its bitter cold captured the weather headlines the past few days but snow has also been a big weather story this winter.  We have nearly tripled the amount of snow we typically have up to this point in the season.  So far 34.7″ of snow has fallen.  In an average winter we would have 12.3″ to date.  We have seen more snow than Bismarck (19.9″), Minneapolis (17.3″) and even Green Bay (27.6″).  If we get even average snowfall for the rest of this season it would bring our total up to 58.9″.  There have only been ten other snow seasons with higher snowfall since the winter of 1884-1885.  The official winter (December through February) snowfall is up to 33.8″.  If we continue to get average snowfall through February our total would be 51.1″ or the 9th snowiest winter on record.

We started the year off with one of the snowiest weeks on record.  Nearly two feet of snow fell between December 30th and January 5th.  23.1″ of snow fell during that nasty 7 day stretch or nearly two thirds of our entire snowfall for the season (67%).  That is the 7th highest 7 day snowfall total on record.  The worst week for snowfall occurred in 1967.  29.9″ of snow fell between January 25th and February 1st that year.


Our snow cover will be shrinking very soon as we warm up above freezing high temperatures from Friday through early next week.  Just over half the country (50.3%) is reporting snow cover with an average depth of 4″.  Mild Pacific air will displace the last vestiges of the bitter cold that gripped the area the past few days.



Tim’s Weather World: The fickleness of forecasting snow


We’ve been watching the models for signs of significant snowfall this Sunday ever since they hinted at the possibility earlier this week.  Just yesterday the European model was touting a robust snow producer that could lay out up to 8″.  The latest model solutions have pulled way back.  The European model is now suggesting 1-4″ is more likely with the city and areas southward getting the low end of the range or barely anything at all.  The GFS model didn’t waiver as much also sticking to a similar solution of under an inch in the city and southward.

Tim ECMWF Snow Accum.


While changing snowfall forecasts can be frustrating they are to be expected.  Snowfall amounts are one of the most difficult things to forecast.

There are many factors that influence snowfall forecasts.

  • Duration of the storm-When will it begin? How long will it last?
  • Track of the storm-a 100 mile wobble could mean the difference between flurries and a foot of snow.
  • Lake effect enhancement-will the storm be supercharged with a wind off the lake adding to totals?
  • Snow to liquid ratio-colder storms could fluff up to 20″ of snow or more from one inch of liquid while 10″ snow is the average.
  • Ground temperature-a warm ground could melt snow initially lowering the total accumulation.
  • Moisture-will thunderstorms in the warm sector suck up moisture that could have added to snowfall totals?

In other words, stay tuned because the forecast could change and probably will.



Tim’s Weather World: A Sunday smattering or smackdown?

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What a start to the snow season!  We have had at least flurries 8 of the last 9 days and we are forecasting at least flurries for 5 of the next 7 days.  O’Hare has seen just under 10″ of snow for the season.  That nearly doubles what we typically see through this point of winter.  Last year we only had a trace of snow so far.

After a quick shot of .5″ to 1″ of snow thi smorning the next significant snow will probably fall on Sunday.  The computer model solutions aren’t exactly in agreement at this point.  The European model (see image below) is suggesting a more robust storm with total accumulation by Sunday night at nearly 10″.  About an inch of that will fall prior to the Sunday storm.  The GFS model (see image below) is spitting out 1.7″ total accumulation through Sunday night with .4″ coming prior to the Sunday storm.

Tim Midwest - ECMWF 10 Day Snowfall Accum

Tim Midwest - GFS 10 Day Snowfall Accum

Either way, the prospects for a white Christmas are excellent.   Both models agree cold air will follow the snow so any snow that falls should stick around for several days.

Fun snow fact of the day…

As of yesterday, 46% of the contiguous US had snow cover with an average depth of 3.5″.