chubbs

You have to be careful using raw data from multiple station sites with different baseline temperatures; airport vs downtown for instance. Per NOAA, who corrects for site differences, the past 10 winters in Cook county (2015-2024) were 4.6F warmer than 1895-1930 and the last 5 years (2020-2024) 5.8F warmer. Independently, Madison,Wisconsin Lake freeze data going back to 1852 shows much shorter duration of ice cover now vs the 19'th century and the 1960s and 1970s don't stand out as cold decades. (Mendota and Monona Lakes below.) https://climatology.nelson.wisc.edu/first-order-station-climate-data/madison-climate/lake-ice/history-of-ice-freezing-and-thawing-on-lake-monona/

???? The Chicago airport winter temperature trend is similar to east coast airports (and Detroit). Per the trendline Chicago winters are 5-6F warmer than 60 years ago. Snowfall is more variable locally, but I don't see big differences between Chicago and the east coas teither: 2000+2010s were good, and recent 5-9 years bad. Like many colder east coast cities a snow downtrend hasn't clearly emerged in Chicago despite the warmer winters. That is as expected due to greater snow variability and competing temperature and moisture effects.

Yes weaker is better when the PV is in the arctic, but Hudson's Bay is a different situation. In that case, stronger can help lock in the TNH+ pattern (per Webber) and provide a nearby cold air source. That said, Webber wasn't concerned about it on another forum.

I am also wondering about the impact on the Hudson's Bay vortex itself. An open Hudson's Bay could make it more difficult to maintain a strong vortex near the Bay. Doubt the TNH analogs have an open Hudson's Bay in mid-Dec.

Wondering how the open Hudson Bay impacts our winter weather with a prominent Hudson's Bay vortex expected this winter

While the climate news is not good, the alternatives to fossil fuels look better and better every day. Below is a short blog article on where energy systems have been; and where they are headed, from an alternative energy expert at Eindhoven Univ., Netherlands https://aukehoekstra.substack.com/p/how-our-thinking-about-an-energy

GISS was 1.31 in November. In the past decade the strongest warming has occurred in the northern mid-latitudes where reduction in aerosols has the biggest effect. A larger aerosol effect implies a larger historical warming from ghg to compensate for increased aerosol masking.

Wondering if the break-up of sub-tropical stratocumulus decks with warming as described in the 2019 paper below contributed to the albedo reduction. Note that the 1200ppm CO2 threshold cited by the paper would vary depending on local conditions. Some areas may be close to the threshold today. https://www.nature.com/articles/s41561-019-0310-1

Zeke Hausfather has a blog on how unusual global tempertatures have been in the current nino. Below is his chart for moderate, strong and super nino covered by the ERA5 reanalysis. This nino was unusually warm at the beginning and recently increasingly so at the end. Only Dec 1958, a 2-year nino, has late warmth similar to this year. Still some hope for further post-nino cooling, based on 1958 and current relatively warm ONI, but we are in the 4'th quarter of this nino cycle. https://www.theclimatebrink.com/p/how-unusual-is-current-post-el-nino

Think we've seen enough to expect the same or bigger warming impact from this nino as 2015/16, i.e., roughly 0.3C warming. The two ninos combined have moved us quite a climate distance from the hiatus period, 2 or 3 decades of warming at 0.2C per decade. Going to take a while to sample enough weather in our new temperature range to see what the implications are.

This abstract for Dec AGU meeting has the best explanation I have seen for the unusual warmth since last summer. Per bar chart on right below about half of this nino's heat (atmosphere, AHC, and 0-100m ocean) came from the 100-300m layer in the ocean and half from the earth's energy imbalance. https://agu.confex.com/agu/agu24/meetingapp.cgi/Paper/1553238 Global and Regional Drivers for Exceptional Climate Extremes in 2023-2024: Beyond the New Normal Plain-language Summary In this study, we examined the 2023-24 global heating event, exploring whether it was exceptional in the context of global warming. We developed the Abnormal record-Breaking test (AB-test) to assess if global surface air and sea surface temperatures, along with atmospheric and upper ocean heat content, were exceptionally high. The results indicated these metrics were at record-breaking levels from June 2023 to June 2024. The significant rise in heat content was attributed to a strong El Niño event and an unprecedented Earth's Energy Imbalance (EEI), which contributed to the extraordinary nature of this heating period. The EEI, in particular, was identified as a key factor making this event special. The study also highlighted regional factors, such as reduced cloud cover and unique atmospheric circulation patterns, that contributed to warming in specific areas like the southeastern tropical Atlantic and the Southern Ocean. These findings emphasize the combined influence of a strong El Niño and an unprecedented EEI, along with regional contributors, in driving the exceptional 2023-24 global heating event.

Consistent with the warm October temps above 80N, sea ice volume growth was slow in October and 2024 fell to 2nd lowest volume as of Oct 31. Only 2020 was lower.

One thing I've noticed recently, the cool SST area south of Iceland and west of Great Britian/Ireland, associated with a potential slowdown in the overturning circulation has warmed; and, a new cool SST area has developed to the SW east of the US. We'll have to see if the change persists long enough to be relevant to the ocean circulation discussion.

The chart below runs through Oct 30 and the last data point for 2024 is close to the October monthly avg. October will be a very warm month globally. Not that far from last year despite the transition to nina conditions and around 0.45C warmer than 2016. The gap between 2024 and 2016 has been steadily widening since early in the year. Both the beginning and end of this nino cycle are warmer than expected. However, this October is not quite as gobsmacking as last September which ran roughly 0.6C warmer than 2015.

I hear you, guess I should have added a "relatively" in front of the good. To add more context, the relatively good news is that NOAA version of ocean heat content is not accelerating. Last year, CERES satellite data showed that the earth was taking on heat at an increasing rate. That heat ends up mainly in the ocean and should result in an acceleration in ocean heat content. The recent satellite data is also relatively good news per this recent chart from Gavin Schmidt (data through July). There is a decade over decade increase, but hard to make a case for short-term acceleration, as some were doing last year. As I stated above I am keeping an open mind on the past couple of years. We are going to need more pieces to put this puzzle together.