bluewave

Yeah, it was their 3rd coldest October temperature on record. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1976 30 0 - 1966 30 0 - 1962 30 0 2 1988 31 0 3 2020 32 0 - 2011 32 0 - 1974 32 0 - 1969 32 0 - 1965 32 0

Yeah, that looks close to the record for after the first week of November. JFK may have set the all-time November dew point record of 68° in November 2019. But that was earlier on the 1st. https://www.wunderground.com/history/daily/us/ny/new-york-city/KJFK/date/2019-11-1 11:51 PM 68 F 68 F 100 % S 40 mph 54 mph

With the exception of 77-78, the 70s were notorious for underperforming snow for the amount of cold we had. We don’t seem to get cold and dry winters anymore. Most of our cold winters since 2000 had 40”+ to 50”+ snowfall seasons.

This fall seems to be following the pattern since 2010. The years with an early freeze in October have had the warmest Novembers. Last year was the coldest November at Newark but didn’t drop below 40° in October. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Year Lowest Min Temperature Nov Departure 2020 32 ? 2019 40 -4.0 2018 34 -3.1 2017 40 -0.7 2016 37 +2.9 2015 31 +5.2 2014 39 -2.9 2013 33 -2.4 2012 34 -3.5 2011 32 +4.1 2010 38 +0.5

Don recently posted a very informative paper on the topic. https://www.nature.com/articles/s41598-020-71945-4 Extreme weather events in Asia have been occurring with increasing frequency as the globe warms in response to rising concentrations of greenhouse gases. Many of these events arise from weather regimes that persist over a region for days or even weeks, resulting in disruptive heatwaves, droughts, flooding, snowfalls, and cold spells. We investigate changes in the persistence of large-scale weather systems through a pattern-recognition approach based on daily 500 hPa geopotential height anomalies over the Asian continent. By tracking consecutive days that the atmosphere resides in a particular pattern, we identify long-duration events (LDEs), defined as lasting longer than three days, and measure their frequency of occurrence over time in each pattern. We find that regimes featuring positive height anomalies in high latitudes are occurring more often as the Arctic warms faster than mid-latitudes, both in the recent past and in model projections for the twenty-first century assuming unabated greenhouse gas emissions. The increased dominance of these patterns corresponds to a higher likelihood of LDEs, suggesting that persistent weather conditions will occur more frequently. By mapping observed temperature and precipitation extremes onto each atmospheric regime, we gain insight into the types of disruptive weather events that will become more prevalent as particular patterns become more common Over Siberia they found a significant increase in the frequency and duration of warm spells and wet days, while central Asia saw more cold spells and wet days, and east Asia experienced more long wet spells. These results are consistent with an increased (decreased) prevalence of the pattern in node #1 (#12). They also found that warm, wet, and dry spells predominantly lengthened in most parts of Asia, suggesting a general increase in persistence. Another study14 analyzed output from several atmosphere-only models forced by sea-ice and ocean-temperature conditions consistent with a 2 °C warmer world. Similar to our results, they found significantly increased persistence of warm spells over northern and central Asia, as well as wet spells over northern and eastern Asia. In addition to supporting previous findings, our study demonstrates an increasing frequency of persistent large-scale circulation regimes and associated extreme weather events, especially since the mid-1990s when AAW emerged as a clear signal. As greenhouse gases continue to accumulate in the atmosphere owing to ongoing human activities, we find that patterns characterized by warming in high latitudes will occur more frequently while cold-Arctic patterns will decline. A higher percentage of days/year in any one pattern will increase the likelihood of multiple consecutive days occurring in that pattern, leading to more frequent persistent conditions. Moreover, we demonstrate that the predominant warm-Arctic pattern also exhibits a higher probability of long LDEs occurring relative to days belonging in a node, thus further augmenting the likelihood of persistent weather events. Three of the climate models participating in CMIP5 agree that warm-Arctic patterns will increase several-fold by the end of the century at the expense of cold-Arctic patterns, suggesting a substantial rise in the frequency of persistent circulation regimes and their associated extreme weather. The connections with changes in jet-stream characteristics, such as blocking and other cut-off circulation features, will be addressed in future work.

These big weather swings have become the new normal.

You have to search for virtual lab gfs mos to get the new site. I only wish that that they also had ECMWF mos products. I believe the only access to that is on the NWS AWIPS in house system. https://vlab.ncep.noaa.gov/web/mdl/mos-products

Looks like 60s and 70s until further notice as the WAR pattern really locks in. KEWR GFSX MOS GUIDANCE 11/03/2020 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 TUE 03| WED 04| THU 05| FRI 06| SAT 07| SUN 08| MON 09| TUE 10 CLIMO X/N 54| 38 61| 48 69| 52 70| 54 72| 55 72| 58 73| 56 68 40 56 KISP GFSX MOS GUIDANCE 11/03/2020 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 TUE 03| WED 04| THU 05| FRI 06| SAT 07| SUN 08| MON 09| TUE 10 CLIMO X/N 52| 33 59| 47 65| 52 70| 51 68| 51 69| 53 70| 56 68 38 56

We could challenge the all-time November 500 MB positive height anomaly record this weekend. It looks like the record for the NYC area is 589 DM. The models all have values close to that level.

We broke the March cold streak this year so I guess it was only a matter of time before we had a warmer than normal November. These have been the only reliably cooler than average months in recent years. Getting more than 3 consecutive colder Novembers and Marches is just too much to ask from this warmer climate. NYC Nov 17...-1.1 Nov 18...-3.3 Nov 19...-3.8 Mar 17...-3.3 Mar 18...-2.4 Mar 19...-0.8 Mar 20...+5.5

The EPS weeklies are warmer than normal until further notice as the WAR pattern really locks in.

Gusting into the 40s along the coast. Jones Beach N/A 43 N/A N/A W30G43 N/A Wantagh N/A 41 28 60 W22G43 N/A Hempstead NOT AVBL Matinecock Pt N/A 43 N/A N/A NW33G46 N/A

Looks to be a very slow mover with such a strong blocking ridge to the north.

The coming warm up will get a boost from one of the most impressive WAR patterns we have seen during the month of November. The strongest ridge that I could find in the OKX soundings for November was 589 DM. The ensemble forecasts have the potential for a 588 DM+ ridge by the weekend.

New record lowest October average extent. There have been 10 new monthly lowest average extent records set since 2016. The only remaining monthly records are August and September 2012.

The last 3 Novembers in NYC were colder than average. But this year is starting out differently. The previous 3 years began the month warm and shifted colder by the 2nd week of the month. This year the coldest days for a while will be on the 2nd 3rd with a rebound back to the mild 60s. So it will be interesting to see if this means that we will finally see a milder than normal November. Nov....EWR...NYC...LGA 2019...-4.0....-3.8.....-3.7 2018...-3.1....-3.3....-2.7 2017...-.0.7....-1.1....-0.3 KNYC GFSX MOS GUIDANCE 11/01/2020 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 SUN 01| MON 02| TUE 03| WED 04| THU 05| FRI 06| SAT 07| SUN 08 CLIMO X/N 56| 36 45| 39 51| 39 57| 51 67| 55 68| 56 68| 59 66 42 56

While the record cold around the Rockies and Plains has been impressive, it’s focused over a very small geographic region of the planet. The coverage of the record cold is much smaller than the areas and magnitude of record warmth as the world warms. It’s no coincidence that the record October cold near Montana is occurring in an isolated pocket relative to the overall extent of the global temperature increases. Montana represents a portion of the only 17 out of 2,844 stations with under 6 months of warming over the last 30 years.

https://nsidc.org/arcticseaicenews/faq/#area_extent What is the difference between sea ice area and extent? Area and extent are different measures and give scientists slightly different information. Some organizations, including Cryosphere Today, report ice area; NSIDC primarily reports ice extent. Extent is always a larger number than area, and there are pros and cons associated with each method. A simplified way to think of extent versus area is to imagine a slice of swiss cheese. Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Area would be the measure of where there is cheese only, not including the holes. That is why if you compare extent and area in the same time period, extent is always bigger. A more precise explanation of extent versus area gets more complicated. Extent defines a region as “ice-covered” or “not ice-covered.” For each satellite data cell, the cell is said to either have ice or to have no ice, based on a threshold. The most common threshold (and the one NSIDC uses) is 15 percent, meaning that if the data cell has greater than 15 percent ice concentration, the cell is considered ice covered; less than that and it is said to be ice free. Example: Let’s say you have three 25 kilometer (km) x 25 km (16 miles x 16 miles) grid cells covered by 16% ice, 2% ice, and 90% ice. Two of the three cells would be considered “ice covered,” or 100% ice. Multiply the grid cell area by 100% sea ice and you would get a total extent of 1,250 square km (482 square miles). Area takes the percentages of sea ice within data cells and adds them up to report how much of the Arctic is covered by ice; area typically uses a threshold of 15%. So in the same example, with three 25 km x 25 km (16 miles x 16 miles) grid cells of 16% ice, 2% ice, and 90% ice, multiply the grid cell areas that are over the 15% threshold by the percent of sea ice in those grid cells, and add it up. You would have a total area of 662 square km (255.8 square miles). Scientists at NSIDC report extent because they are cautious about summertime values of ice concentration and area taken from satellite sensors. To the sensor, surface melt appears to be open water rather than water on top of sea ice. So, while reliable for measuring area most of the year, the microwave sensor is prone to underestimating the actual ice concentration and area when the surface is melting. To account for that potential inaccuracy, NSIDC scientists rely primarily on extent when analyzing melt-season conditions and reporting them to the public. That said, analyzing ice area is still quite valuable. Given the right circumstances, background knowledge, and scientific information on current conditions, it can provide an excellent sense of how much ice there really is “on the ground

The last few days set the new all-time extent anomaly record.

All the extra ocean heat on the Siberian side is really slowing the freeze-up this October. So the the extent is currently the lowest on record for this time of year well below 2012. The Siberian heatwave this year was one of the most extreme events we have seen.

Yeah, we are well below where 2012 was at this point in October. The the heat on the Siberian Arctic side this year was off the charts. 5.422 7.329 6.871 6.596 5.715 6.515 5.681 5.234 5.108

Very unusual to see a daily area drop in mid October as the record Arctic warmth is slowing the freeze-up https://cryospherecomputing.tk

The record SST warmth form the Siberian heatwave is slowing down the freeze- up in those regions. https://theconversation.com/arctic-sea-ice-is-being-increasingly-melted-from-below-by-warming-atlantic-water-144106 All this may be feeding into ever more extreme climate change in the Arctic. Throughout summer 2020 the Siberian heatwavecontinually shattered temperature records, including eastern Arctic sea surface temperatures. And while sea ice reflects much of the sun’s rays back into space, open water is dark and absorbs the sun’s heat. So as the sea ice retreated the surface water is warmed, which in turned further warms the atmosphere above, quite apart from the influence of increasing greenhouse gases. There is still much more to learn about the link between the eastwards spread of the influence of Atlantic heat, and the reduction in sea ice it brings, and knock on effects on severe weather at lower latitudes. But it is clear that the Arctic – already warming faster than anywhere else on Earth – could be in the process of transitioning to a “new” state.