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Here's the F6 but only goes back to 1996. But at least you feel confident its official and fill in missing years you have. Then use link above for previous years. Central Indiana Climate Information
This is from our local weather blog posted way back in 1999
Quote:
Chicago's autumn temperatures offer a clue about the coming winter's readings only when substantially warmer or colder than average. Fall temperatures less than 2.5 (degrees) from historic averages yield no statistically significant correlation with the winter temperatures which follow--winters turn out warmer and colder than average with about equal frequency after such falls. This autumn falls into that category. To date, Chicago temperatures since Sept. 1, despite recent record-breaking warm spells, are just a degree above normal.
These conclusions derive from a detailed computer analysis of Chicago weather records back to 1872 by my colleague, meteorologist Richard Koeneman. He's found that winters that follow September through November periods more than 2.5 (degrees) above or below historic norms do serve as indicators of the coming winter. Winters that follow such falls tend to reverse the autumn temperature trend--i.e. very warm autumns lead to cold winters while chilly falls are followed by mild winters.
What I find more interesting is overall trends with respects to La Nina and El Nino on local climate during various seasons
Quote:
Though La Nina's global effects are generally considered less pervasive than El Ninos, in-house analyses have linked a slight tendency toward wetter than normal springs with the event. Stronger La Ninas have impacted summer weather here. In eight of nine warm seasons since 1950 identified as having coincided with La Ninas comparable to the one predicted this summer, Chicago temps have averaged warmer than normal overall from June through August. These years have produced an average of 33 days of 90s at Midway Airport, more than the average of 24 since 1928.
Quote:
El Niño" is not a meteorological event, but its occurrence has huge effects on the world's, and Chicago's, weather. El Niño is an abnormal warming (by a few degrees) of water in the equatorial belt of the Pacific Ocean westward from South America. El Niños, when they occur, usually last up to about 18 months. They have little impact on U.S. temperature and rainfall patterns during the summer and early autumn, though they can help to suppress Atlantic Ocean hurricane activity. Late autumn and winter is another story. At Chicago, "El Nino winters" are usually milder and less snowy than normal, sometimes dramatically so if the El Niño event is especially strong. For now, an El Niño is not expected.
There was an El Nino in 2009-2010 that should have given us a milder drier winter, but it was overrun by a consistently negative Arctic Oscillation.
And the moderate La Nina in 2011-2012 basically gave us a very mild dry winter. If it was a stronger La Nina, there might have been more Arctic incursions.... 2007-2008 was cold and snowy but at the same time we had wild gyrations in temps. January 2008 Chicago topped 65 degrees, and we actually had a tornado outbreak
2008-2009 was a second La Nina year which that January saw extremely cold temps here, and overall a colder then normal winter. Lots of snow too.
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