Our first flurries of the season arrived almost two weeks ahead of schedule on Tuesday. The trace amount of snow reported at O’Hare actually tied the record snowfall for October 22. Only 37 more inches to go! The average snowfall for the past twenty winters is a smidge over 37″.
While flurries flew again yesterday and early today there wasn’t enough snow to stick. It now appears there won’t be a need for even a scraper through next weekend. The 10 day total snowfall accumulation forecast from both the GFS and ECMWF models (see images below) show no snow after today through next Sunday morning. The GFS does spit out .1″ for Chicago but that refers to today’s flurries.
By the way….
6.6% of the contiguous US has snow cover today compared with 9.9% on this date last year.
The Climate Prediction Center updated their seasonal forecast for this winter recently and unfortunately it doesn’t offer much of a clue as to what we can expect. For both the precipitation and temperature outlook we are outlooked “EC”(see images below). EC stands for equal chances of being either above or below average. In other words, you can flip a coin.
ENSO-neutral conditions are expected to continue through this winter which is part of the problem. ENSO refers to the El Nino Southern Oscillation. El Nino is unusually warm ocean temperatures in the equatorial Pacific. Right now the Pacific is neutral or between an El Nino and a La Nina (unusually cold equatorial Pacific). The model forecasts (see below) keep the Pacific in neutral conditions through the summer of 2014. Each colored line on the graph below represents a model forecast. Above 1 would indicate El Nino conditions and below -1 would indicate La Nina conditions. All models are between 1 and -1 indicating neutral conditions expected through next summer.
After crunching some numbers there may be some indication that this winter could see slightly less snow than average and be slightly warmer than average. I looked at the last ten winters that occurred during ENSO-neutral conditions. The average snowfall during those winters was 32.76″. The average snowfall for Chicago is 36.7″. The average temperature during the ENSO-neutral winters was 27.4° . The average temperature for a Chicago winter is 26.4° . Take that with several grains of salt though. The presence or lack of El Nino is just one of several variables that has an effect on our winter forecast.
Highs fall back into the 50s today as the coolest air of the season sweeps in on west winds. The cool air appears to be here to stay. There are a couple of days in our 7 day forecast that get close to 60° but highs will be in the 50s for most of the next week. The Climate Prediction Center’s 6 to 10 day and 8 to 14 day forecasts (see images below) have us outlooked for cooler than average weather. That would mean that nearly the rest of this month will be cooler than average overall.
Cool to cold air is sinking southward all the way to Texas. The Lone Star State is one of ten states that has either frost advisories or freeze warnings in effect. Winter weather advisories and winter storm warnings are posted for portions of New Mexico and Colorado. The hardest hit areas in south central Colorado could see up to a foot of snow in the higher elevations.
The Northwoods of Wisconsin and other parts of the midwest could see some of the first snowflakes of the season Friday with more light snow at times over the weekend.
The month of October started off mild. 11 of the first 13 days were above average. 10 of the first 13 days had a high at least in the 70s. The jet stream pattern is changing and the result is going to be seasonably cool 60s for the next couple of days followed by highs in the 50s from Wednesday through the weekend. The longer range forecast from the Climate Prediction Center keeps us cooler than average through the third week of the month (see image below). The latest 6 to 10 day outlook has most of the country and all of the midwest outlooked for below average temperatures from October 19-23.
It could always be worse….
While frost was our biggest problem this morning, out west there are 5 states with winter weather advisories or winter storm warnings in effect. Parts of the Rockies could see upwards of a foot of snow at the higher elevations.
Photo courtesy of Ed McGill
Days continue to grow shorter and nights longer as we get deeper into autumn. We have lost nearly 4 hours of daylight since the start of summer. All part of the process that leads to leaves changing color this time of year. More beautiful weather is on tap to enjoy the fall colors that are on display. They have peaked already in northern Wisconsin but are beginning to peak in northern Illinois and Indiana.
Some scientists have suggested that global warming has delayed the onset of fall colors by three to five days in some regions over the past 23 years. Warmer weather is also associated with a less vibrant than usual array of colors.
Here are some resources for more information on fall foilage:
No signs of a freeze any time soon. We should top 70° today and enjoy a streak of days with a high of 70° or more straight through Saturday. However, this is fall and it’s just a matter of time before we see temps dip to 32° or colder. On average, the first fall freeze usually occurs any time between now and the second or third week of October depending on your location. The first fall freeze typically occurs latest in the city and earliest north and west.
The average date of the first freeze of the season (32° or colder) is October 12th. We have seen the first freeze as early as September 22 back in 1995 while the latest first freeze occurred on November 24th in 1931.
The National Weather Service office in Chicago has more on when to expect the first fall freeze. Illinois State Climatologist Jim Angel has detailed information on frost dates and the growing season for the entire state of Illinois.
A major storm packing strong winds, heavy rain and snow may spin up late Thursday into Friday in the plains. We will be impacted by the storm initially with a surge of warm air on its front side but eventually colder air will come crashing in Sunday as the storm’s center lifts just north of here. So it will be a tale of two seasons here. Today it will feel just like July with a high near 84°. By Sunday it will feel like fall again with highs failing to climb above the 50s. Between now and then there will be periods of showers and thunderstorms that could produce some locally heavy rain at times. The GFS model is hinting at the possibility of 1 to 2 inches of rain in total.
The GFS model is spitting out more than a foot of snow for portions of the plains. The graphic below is the total accumulated snowfall expected between now and early Monday. Most of that snow would fall Friday into Saturday.
While snow flies out west, strong thunderstorms in the storm’s warm sector could hit the midwest late this week. The Storm Prediction Center has outlooked northwest Illinois, much of Iowa, southwest Wisconsin and southern Minnesota for a slight risk of severe weather during the period of Friday into Saturday (see graphic below).
Some welcome rain will fall Saturday night into early Sunday but it won’t be enough to quench the drought that has deepened across portions of Illinois this past week. Our RPM model is spitting out anywhere between a couple of tenths of an inch of rain to as much as a bit more than an inch (see image below). Most of the Chicagoland area is “abnormally dry” but downstate the drought is a bit more dire. Just over 40% of the state is in a moderate drought and nearly 15% is in a severe drought. While the area affected by moderate drought has decreased slightly the area affected by severe drought has jumped almost 5% from a week ago.
Locally, O’Hare has recorded 2.19″ of rain so far this September, down .64″ from average. Since the start of August 3.88″ of rain has fallen, down 3.85″ from average.
Other than the showers that will accompany a cold front Saturday night, there is very little rain in our forecast through Thursday next week. However, the 6 to 10 day outlook from the Climate Prediction Center has outlooked most of the eastern half of the country, included the midwest, for above average precipitation during the first week of October (see image below).
Craig J. Tucker
Picture perfect September weather will continue today with sunshine & 70s. Speaking of pictures, click on the photo above to see Chicago Tribune’s gallery of weather photos submitted by readers.
Keep your camera ready. The outlook for the end of September and start of October includes mild and mainly dry weather despite yesterday marking the fourth day in a row below average. That trend is about to change for the warmer. We will continue to warm through the end of the week and start of the weekend with highs above 80° on Saturday. While we will see temps drop Sunday, next week should start off above average.
The longer range outlook from the Climate Prediction Center is calling for an overall above average October. The vast majority of the country is outlooked for an above average month. The average high temperature for O’Hare drops from 68° at the start of the month to 56° at the end of the month.
Our first full official day of fall started off cold north and west of the city this morning. Here are some of the colder morning lows from our WeatherBug network:
- 39° Kenosha
- 41° Island Lake
- 42° Wadsworth
- 42° Aurora
- 42° Valparaiso
- 42° Union
O’Hare’s low of 47° ties the low on September 14th as the coldest since early June. We weren’t the only ones feeling the chill of fall, there were 9 states with either frost advisories or freeze watches and warnings in effect this morning including the northwoods of Wisconsin. The National Weather Service office in Boulder, Colorado was expecting snow levels to drop to as low as 9000-9500 feet this morning with as much as 4″ of accumulation possible (see photo below).
Thanks to Ed Gruhlke of Plymouth, IN for the beautiful moon shot.