bluewave

Same to all the great members that we have on the forum.

This looks more like LA with the smog trapped under the inversion.

Almost difficult to keep up with all these record breaking rainfall events.

You know it’s the 2010’s when Chicago gets record snowfall on Halloween and none on Christmas.

Updated for 3.44 in Woodbury, NY. https://nwschat.weather.gov/p.php?pid=201912141224-KOKX-NOUS41-PNSOKX WOODBURY 3.44 704 AM 12/14 CWOP

The Meadowlands will now have snow and 28 degrees 365 days of the year. https://www.inquirer.com/business/big-snow-american-mega-mallski-slope-mall-meadowlands-20191212.html

The record amount of open water for the Chukchi Sea continues to be one of the big stories this year.

That was a very cold -NAO/+PNA pattern for the first week of December 2003. It was the snowiest first week of December and the 11th coldest for NYC.

Another recent paper highlighted how unusual the initiation of the March 2015 unprecedented MJO event in phase 4 was. This helped trigger the 2015-2016 super El Niño event. https://www.nature.com/articles/srep46692 The emergence of this convection–circulation pattern signaled the onset of an MJO that later strengthened to an unprecedented amplitude (MJO real-time multivariate index24 of 4.62 on March 16, 2015 compared with the previous record of 4.02 on February 14, 1985; http://www.bom.gov.au/climate/mjo/) during its eastward propagation over the tropical Pacific in March (Fig. 2c)13. In contrast to the canonical MJOs, which typically originate in the tropical IO, the MJO in spring 2015 initiated in the western Pacific. Our analysis revealed that only 3 out of the 75 large-amplitude MJOs (occurring in 1975, 2013, and 2015; approximately 4%) during 1974–2015 initiated in the western Pacific (i.e., phase 4 of the MJO index24, Supplementary Figure 2). Notably, only in 2015, the MJO preceded the onset of an El Niño event. No eastward-propagating tropical signals from the west but strong extratropical perturbations were observed preceding the 2015 MJO event; this lead–lag relationship implies the potential extratropical effect on triggering the MJO. Furthermore, the percentile values reported in Figs 1 and 2 show the unprecedented amplitudes of the extratropical SLP, northerly, WWB, tropical SLP anomaly crossing the central and eastern equatorial Pacific (Fig. 1c), and the MJO strength. This observation revealed the distinct characteristics associated with this MJO: the effect of extratropical forcing, atypical genesis location and timing, and the extremity of amplitudes in many aspects. The warm ocean surface in the equatorial western Pacific might be another favorable condition conducive to MJO occurrence. A vertical cross section of the monthly ocean temperature along the equator (Supplementary Figure 3) revealed that the upper ocean in the central Pacific was approximately 1.5 K warmer in February–April 2015 than the long-term mean. This warming in the central Pacific was markedly higher than that during the onset of the 1997–98 El Niño. A previous study13 reported the effect of this warm water on MJO development in early spring 2015. An analysis of the SST evolution since early 2014 indicated that the warm SST in the central Pacific was primarily the remaining positive SST anomaly from the aborted 2014 El Niño (data not shown). The extratropical forcing in late February likely triggered the anomalous convection over this warm water and initiated the rigorous atmosphere–ocean interaction in the tropical western and central Pacific and onset of a strong MJO event. Conclusion and Discussion An atypical MJO initiated to the west of the dateline in early March 2015 and rapidly amplified to an unprecedented magnitude over the warm SST in the central and eastern Pacific on March 16. Following the MJO, the SST in the equatorial central–eastern Pacific encountered rapid growth and ultimately evolved to a strong El Niño comparable with the 1982–83 and 1997–98 events. Before the MJO onset, we observed a persisting high-pressure system accompanied by strong cold northerly in the extratropical western North Pacific. On the basis of data diagnostics and numerical experiments, we identified an atypical effect of extratropical perturbations in the western North Pacific on triggering the onset of the MJO in March 2015 and indirectly contributing to the onset of the 2015–16 El Niño. The main results are summarized as follows: 1 Observational analysis indicated that the strong cold northerly, which was associated with a persisting high-pressure system in the extratropical western North Pacific, penetrated southward to the tropical western Pacific and triggered the tropical convective instability that led to the onset of the MJO at an atypical location, namely west of the dateline. The critical effect of the extratropical disturbances on the MJO onset was confirmed by numerical experiments by using an atmospheric general circulation model coupled with an ocean mixed layer model. 2 The MJO developed rapidly to an extreme magnitude because of the favorable ocean conditions: a warm upper ocean temperature in the equatorial central and western Pacific remaining from the aborted 2014 El Niño. 3 Both data diagnostics and numerical experiments revealed that the strong WWB associated with the MJO triggered the first pulse of downwelling Kelvin wave-like perturbations that later induced the onset of the 2015–16 El Niño. Extratropical forcing was the unique characteristic of the reported MJO–El Niño event. The onset of El Niño by an MJO has been observed often. However, according to our review of relevant literature, the present study is the first to report the onset of an El-Niño-inducing MJO in the western Pacific triggered by extratropical perturbations. Extremity was another unique characteristic. Several aspects of perturbations, such as extratropical and tropical SLP, northerly, and the MJO reached unprecedented amplitudes. The reasons for these unique characteristics remain unknown. However, our study revealed the possible effect of extratropical forcing, which has not been considered previously, on the onset of MJO and El Niño. Such a mechanism, although it might not occur frequently, warrants further attention and may elucidate the onset of an MJO and its potential effect on El Niño.

https://www.nature.com/articles/s41586-019-1764-4 Article Published: 27 November 2019 Twofold expansion of the Indo-Pacific warm pool warps the MJO life cycle Nature volume 575, pages647–651(2019)Cite this article Article metrics 23 Altmetric Metrics details M. K. Roxy, Panini Dasgupta, Michael J. McPhaden, Tamaki Suematsu, Chidong Zhang & Daehyun Kim Abstract The Madden–Julian Oscillation (MJO) is the most dominant mode of subseasonal variability in the tropics, characterized by an eastward-moving band of rain clouds. The MJO modulates the El Niño Southern Oscillation1, tropical cyclones2,3 and the monsoons4,5,6,7,8,9,10, and contributes to severe weather events over Asia, Australia, Africa, Europe and the Americas. MJO events travel a distance of 12,000–20,000 km across the tropical oceans, covering a region that has been warming during the twentieth and early twenty-first centuries in response to increased anthropogenic emissions of greenhouse gases11, and is projected to warm further. However, the impact of this warming on the MJO life cycle is largely unknown. Here we show that rapid warming over the tropical oceans during 1981–2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900–2018 and at an accelerated average rate of 4 × 105 km2(the size of California) per year during 1981–2018. The changes in the Indo-Pacific warm pool and the MJO are related to increased rainfall over southeast Asia, northern Australia, Southwest Africa and the Amazon, and drying over the west coast of the United States and Ecuador. Fig. 1: A twofold expansion of the warm pool. Fig. 2: Changes in the MJO life cycle. Fig. 3: Correlation between MJO phase duration and ocean–atmosphere conditions. Fig. 4: Changes in global rainfall in response to the changes in MJO phase duration. Extended Data Fig. 1 Typical life cycle of the MJO. Extended Data Fig. 2 Annual average period of MJO events. Extended Data Fig. 3 Warm pool area in multiple datasets and breakpoint analysis. Extended Data Fig. 4 Correlation between MJO phase duration and ocean–atmosphere conditions, without removing the trends.

This matches the pattern pretty well. We can still get record cold as the climate warms. But the ratio of record highs to record lows keeps increasing. Record Arctic outbreaks also occupy a much smaller area now. You can see how the October record cold in the Western US was like a tiny ice cube in a global sea of warmth.

Every month since April has featured top 3 warmth in the Arctic. This is a first for April through October. https://www.esrl.noaa.gov/psd/data/timeseries/

Similar to the findings in this recent paper. https://advances.sciencemag.org/content/4/8/eaat6773 DISCUSSION Implications and outlook The doubling of BG halocline heat content over the past three decades appears attributable to a warming of the source waters that ventilate the layer, where this warming is due to sea ice losses in the Chukchi Sea that leave the surface ocean more exposed to incoming solar radiation in summer. The effects of an efficient local ice-albedo feedback are thus not confined to the surface ocean/sea ice heat budget but, in addition, lead to increased heat accumulation in the ocean interior that has consequences far beyond the summer season. Strong stratification and weak mechanical mixing in the BG halocline ensure that significant summertime heat remains in the halocline through the winter. With continued sea ice losses in the Chukchi Sea, additional heat may continue to be archived in the warm halocline. This underscores the far-reaching implications of changes to the dynamical ice-ocean system in the Chukchi Sea region. However, there is a limit to this: Once the source waters for the halocline become warm enough that their buoyancy is affected, ventilation can be shut off. Efficient summertime subduction relies on the lateral surface front in the NCS region between warm, salty water that is denser to the south and cooler, fresher water that is less dense to the north. For longer-duration solar warming (that is, longer-duration ice-free conditions in the region), SSTs on the south side of the front may become warm enough (around 13°C, under the assumption of a 1.5-month ice-free period dominated by solar absorption) that the lateral density gradient is eliminated [see (24)]. It remains to be seen how continued sea ice losses will fundamentally change the water column structure and dynamics of the Arctic halocline. In the coming years, however, excess BG halocline heat will give rise to enhanced upward heat fluxes year-round, creating compound effects on the system by slowing winter sea ice growth.

Updated for the 9th warmest October at EWR and 7th warmest at ISP.

According to the NSIDC data, October 2019 beat 2012 for the lowest monthly average extent. This makes the 3rd new lowest monthly extent record for 2019. It’s also the 10th new lowest monthly extent since 2016. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Monthly_Data_with_Statistics_G02135_v3.0.xlsx 1 2019 5.66 2 2012 5.89 NSIDC lowest average monthly extents Jan...2018 Feb...2018 Mar...2017 Apr....2019 May...2016 Jun....2016 Jul.....2019 Aug...2012 Sep...2012 Oct...2019 Nov...2016 Dec...2016

While the ESS is finally freezing up, Chukchi extent remains at record low levels for the end of October.

Daniel Swain is probably one of the best sources of information on this topic. While all these California wildfire posts probably belong in a different thread, the information below helps people understand the issues involved. https://insideclimatenews.org/news/13112018/california-deadly-wildfires-climate-change-dry-autumn-late-rainy-season-swain-interview What does the recent data show in California? And how are these changes impacting overall rainfall? We are starting to see a trend towards drier autumns in California. It's somewhat new, it's just emerging from the noise, one might say, but it is actually there. This year is going to add another data point in that direction. It matches climate projections. There has long been an expectation that California's so-called shoulder season precipitation would probably decrease—that's autumn and spring. Now what we're starting to see is, especially in the autumn, that process now appears to be underway. It's both an emerging observation but also a projection for the future, a future that maybe isn't really the future any more. That actually doesn't necessarily mean the overall amount of precipitation is decreasing. There's a growing overall concentration of water in the rainy season. Our research suggests that concentration will be a pretty strong indicator of California's future climate. You've made the point that it's problematic to ask whether climate change causes a specific event. Why is that? In any sort of natural system there's never really, in any context, a singular cause of anything. It depends how you define causation, which then is a non-trivial task. It ends up being more meaningful to say, look, we're going to have fires no matter what. Whether they're caused naturally by lightning, by totally innocent human error or by more malicious human intent. It doesn't really matter what started the fire. But the question is, what factors contribute to what happened after the fire starts. The real question is not so much what caused it, because ultimately it doesn't really matter. The question is what made it as bad as it was. Then you can get an answer that, yes, there is a link between wildfire behavior intensity and climate change. As climate change progresses, what is expected to happen with wildfire season? When it comes to wildfire trends, the last five years in California have really been something else. It's really been hard to watch. it's pretty rare to see such large, dramatic step changes as what we've seen in California in the last five to 10 years. We've broken every record, and we've broken them several times. Largest, most destructive, deadliest—all

Highest rainfall total in CT again. https://nwschat.weather.gov/p.php?pid=201910280141-KOKX-NOUS41-PNSOKX WESTPORT 3.04 801 PM 10/27 CWOP

NSIDC put out a tweet about the new record departure.

It sure is.

This was the warmest June through September melt season on record.The earlier areas of open water had more time to absorb the extra heat. So now it’s taking longer for the Arctic Ocean to release the extra heat back to the atmosphere. Perhaps warm water influx through the Bering Strait also played a role. But I have no way of measuring that. Recent winds (drift circulation) and warmer ocean waters from heat gained during the early spring melt-out

2019 continues to expand its record breaking daily low extents for late October. The NSIDC 5 day extent is now 5.503 million sq km as of October 20th. This is well below the previous lowest for the date set in 2007 at. 5.946 million sq km. It also places this year 726 k lower than 2012 which was 6.229 million sq km.

That anomaly grew a little from yesterday. Now at -3.075 as of October 18th. So 2019 continues as the lowest at 5.310 compared to the 5.663 in 2007 and 5.852 in 2012.

Updated for the second breaking storm of the month. New October Record Low Pressures in New England https://www.washingtonpost.com/weather/2019/10/17/powerful-weather-bomb-socks-new-england-with-wind-gusts-mph-knocking-out-power-more-than-half-million/

Updated for 10-16-19 10-17....Norwich, CT...6.15”...numerous 3.00”+ amounts across the area https://nwschat.weather.gov/p.php?pid=201910171436-KOKX-NOUS41-PNSOKX