So will this winter be a snowy one or La Nada like last winter ?
Chicago will be part of the weak to NO El Nino this winter so what is the analog for those types of winters ?
During a weak El Niño, there is generally a war between warmth to the south and the chill to the north. This allows for ample moisture to fuel the winter storms.
During a strong El Niño, the storm track sets up in such a way to allow warm air to overwhelm the Midwest and Northeast; therefore, storms tend to favor rain rather than snow.
There are other oscillations that also have effects on the weather patterns. Last winter we had La Nina and a rather weak AO, Arctic Oscillation. This meant not only a milder pattern from La Nina but the Arctic Air stay well north most of the winter.
Positive AO shows cold air up northNegative AO means more cold
The AO usually fluctuates back and forth between positive (strong jet stream near the Arctic Circle) and negative (weak jet stream near the Arctic Circle) over the course of a winter.
In short, when the AO is strongly positive, the jet stream is strong from west to east around the Arctic Circle and cold air cannot escape southward to the mid-latitudes.
"The persistent, strongly positive AO this past winter was highly unusual and had a profound effect on temperature and snowfall over much of the U.S. and southern Canada,"
Since the clash of cold air with warm air is a key ingredient for storms and cold air is needed for snow, a strongly positive AO greatly reduces the chance of such an occurrence.
Generally, the AO cannot be predicted more than a few weeks in advance. This is the same case for the North American Oscillation.
"However, odds are greatly in favor of the AO either being less strongly positive or at least being negative at times this coming winter, compared to last winter,"
A negative AO is a weaker circulation around the Arctic Circle and allows cold air to drive southward. This is the key to getting snow in Chicago Dec-Feb.
The strongly positive AO throughout this past winter prevented a feature called the Greenland Block from setting up. The Greenland Block tends to lock in sufficient cold air in the northeastern U.S. for approaching storms.
The less strongly positive AO and occasional blocking should at least create more opportunities for snow this winter. This means the NAO will be in our favor for January 2013 that could be the best month for snow.
We are gonna go with the "NO" El Nino idea this winter and on the graph above we think the 1994-1995 year may be looking like the winter ahead of us (2012-2013).
The current state of El Nino is between Neutral and a weak El Nino. NOAA and liveweatherblogs.com weather team have decided to write off El Nino for now so other factors like the NAO AO and Canadian snow cover become the main players in carving out this winter.
Overall Chicago will see temps average a few degrees BELOW normal with the coldest weather Jan 17-February 8th at this point.
SO YOU WANT TO KNOW HOW MUCH SNOW ?
This outlook has been updated March 13, 2013 to reflect the lack of snow in December and early January. We also called for an active February and March and it sure is so far.
SNOWFALL THIS SEASON 29.8"
LIVEWEATHERBLOGS.COM PREDICTION 25.3"
AVERAGE CHICAGO SNOWFALL 37.7"
REGISTER NOW...IT TAKES ALL OF 10 PAINLESS SECONDS
Interesting article-- I have also pictured this CHICAGO winter to be slightly on the mild side, with the exception of a brief arctic plunge towards the mid-to-late January and beginning of February--which *may* trigger some heavy Lake Snows--but I feel it will not be a Chicago thing, more like a South Bend type event... Slightly below average snowfall overall; If we do get big snows, then they will occur much later into 2013. 94-95 sounds right whereas last year was more of an 82-83 type setup (yet, both sucked in terms of snowfall). This winter will NOT be as warm as 2011-12, but it does look to be rather uneventfull---prove me wrong!!!
All eyes will be on Buffalo, NY and Syracuse after their HORRIBLE winter last year! Near Record low snow season...
Yesterday hit 70 degrees at O'Hare and 72 degrees at Midway airports in Chicago. A couple suburban locations hit 73 degrees. Big pattern change coming by next week. NAO negative and AO negative, with big pool of very cold air up in Alaska which might be getting ready to crash down on the Central and Eastern US. Might be a very cold Christmas here!
Last winter was an epic failure of basically all climate forecasters. We were warned that a truly brutal winter was in store for the Midwest, and in the end we got bupkiss. Interestingly, slightly more than half of ENSO neutral winters--52% of them--end up colder than the long term average. But the snowy winter numbers are more impressive. 14 of the 21 snow seasons in ENSO neutral years have been snowier than the long term average--that's 67% of them. This suggests we could have a much different cold season on the way--in terms of both temp and snowfall---than last year. And that's not even taking into account the sudden appearance of high latitude "Greenland-type" blocking which has started showing up from time to time in recent months---another development that, were it to continue, would argue for a colder and potentially snowier winter. There's certainly isnt anything carved in stone, but at least there is hope for extreme weather fans as myself.
This is my first post on this forum. My thoughts on the upcoming winter is that we will see something similar to 2009-2010. Lots of cold shots for the Midwest, many smaller snowstorms, but probably not monster storms, that will probably plague the East Coast this winter. It seems as if the Greenland Blocking pattern has re-emerged this autumn, and is becoming more frequent. Add to that the Arctic Oscillation has been trending negative overall since the middle of September, and that spells cold.