Thursday/Friday temp pullback and gusty “NW” winds to follow Wednesday rainy spells; longer range: impressive late season mild spell due next week; daytime 60s forecast at a time of year when 40s are typical

by: Tom Skilling, Jennifer Kohnke

Posted: Nov 7, 2023 / 10:53 PM CST

Updated: Nov 7, 2023 / 10:53 PM CST

FORECAST MAPS FOR WEDNESDAY THROUGH FRIDAY

WGN WEATHER HEADLINES

ARE EL NIÑOS AND LA NIÑAS BEING IMPACTED BY CLIMATE CHANGE?

As I post this, there’s a WELL DEVELOPED EL NINO IN PROGRESS across the equatorial Pacific — a situation predicted to continue through Spring 2024. This may impact the coming winter here in Chicago.
El Niños have their largest impact globally on winter season weather. While NO TWO El Niños are exactly alike, there are general trends which have often been observed when El Niños occur. Winters tend to be milder and less snowy in many El Niño years here in the Midwest. We’ll see if that actually occurs in the months ahead.
Both trends, above normal temps and near to below normal precip, are incorporated in official NWS seasonal temp and precip trend forecast — including the November through January forecast I’ve included below. Temps during that period are predicted to come in ABOVE NORMAL while precip during the period is forecast to be NEAR TO BELOW NORMAL over a wide swath of the Midwest.

INTERESTING VIEWS ON WHETHER CLIMATE CHANGE IS IMPACTING El Niños AND La Niñas — AND EXPECTED TO DO SO MOVING FORWARD IN TIME THIS CENTURY?

An interesting post within the past week on NOAA’s Climate.gov website authored by Dr. Mike McPhaden, who is a senior scientist at NOAA Pacific Marine Environmental Laboratory in Seattle, WA, and was lead editor of the book “El Niño- Southern Oscillation in a Changing Climate”, looks at whether, as the attached cartoon suggests, climate change is intensifying the impact of El Niños and La Niñas.
McPhadden points to new research published in the journal Nature Reviews Earth and Environment by Dr. Wenju Cai suggesting El Niño and La Niña intensities in the past 50 to 60 years have grown more amplified/intense. Dr. Cai is a senior principal research scientist with Australia’s CSIRO Marine and Atmospheric Research organization and specializes in the role of oceans in climate variability and climate change. He is the Chair of the World Meteorological Organization’s Pacific Panel World Climate Research Program on Climate Variability and Predictability.
The article is careful to approach the subject carefully — but suggests there do seem to be changes in the intensities of El Niños and La Niñas — changes which may amount to 10%.
As McFadden explains in his Climate.gov post, “El Niño and La Niña events are becoming stronger and more frequent, just as we’ve observed in the more recent historical record. The big events pack the most punch, so even though 10% doesn’t sound like much, it juices up the strongest and most societally relevant year-to-year climate fluctuation on the planet. Combined with the other ways global warming has affected ENSO impacts (footnote #4), this amplified cycle translates into more extreme and frequent ENSO-linked droughts, floods, heat waves, wildfires and severe storms like we observed during the recent triple dip La Niña that ended last March and the major 2015-16 El Niño a few years ago.”

TOTAL PRECIPITATION WHICH FALLS AS SNOW

Think the percent of annual precipitation which falls as snow has declined over the past half century — here’s a fascinating analysis which shows you’re right on!
Here’s a look at the change in the percent of annual precip which has fallen as snow over the past 50 years since 1973 from the inimitable Dr. Brian Brettschneider, Alaska-based National Weather Service climatologist, whose climate analyses are ALWAYS fascinating! It’s clear, with comparatively rare exception our warming climate has cut into snowfall’s occurring. It’s worth noting that warming means that when weather system’s DO produce snow, snowfall can be impressive. It’s just happening over less area overall and with decreasing frequency.
It’s interesting to that the trend toward warming and reduced overall snowfall isn’t limited to a large swath of the Lower 48. Studies have shown warming is occurring at three times the rate in the arctic of other regions on the planet.
Check out Dr. Brettschneider’s analyses of temp and snowfall trends in Alaska and areas surrounding in North America’s arctic region.
You can follows Dr. Brettschneider’s posts here: https://twitter.com/Climatologist49