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This does echo the thoughts of Isotherm's seasonal. We wait and watch. At the least the +PNA may help us from torching if indeed it develops.

@CAPE speculating that even if we get a +PNA what about the cold air source? If the EPS is correct Canada is very, very warm. Remarkable, and a sad situation for cold and snow lovers in the East. .

Mentioned the Pac wave train yesterday, and here you have the transition to a +PNA . Today, as you mentioned, more evidence of a + PNA , granted over 600 hours away, but plausible.

IRI update. Maybe some minor implications.

Pacific wave training getting under way soon. If you freeze the animation posted by Anthony you will see the Western ridge amp up and the East Coast trough response near day 9 to 10. I would cold expect a cold period lasting a day or two near the very end of the month. Euro not as thrilled so far. Afternoon run coming up shortly. Keep in mind the same trends as last Fall and winter may once again prevail this upcoming cold season which are the inland runner and Midwest/ GL cutter outcomes.

You can hibernate for the next 10 to 15 days because things look super boring in regards to the weather. However, some interesting developments with regards to SHPV and the NHPV. Currently an extremely cold Southern Hemispheric PV , while the Northern PV is ( quoted by Simon here ) " 100 hPa eddy heat flux averaged over the last 45 days is approaching the 10th %ile in the Arctic " As mentioned yesterday the fires in Aussie and the Western US fires may be responsible here to a degree, as is the QBO. HM mentioned the warmth between the two PVs and the role of aerosols and spoke about a volcanic winter similarity I believe. In my opinion we are witnessing the effects of the change last year with the behavior of the QBO along with the QBO's induced thermal winds manifested upon the aerosol released event, whether acting in unison or separably. Here are a couple great threads that talk about this. One from Dr. Amy Butler and the other from Simon Lee. Each thread is worth clicking on and scrolling through. And for the time being, nothing to be encouraged about. We may be entering as well something called a polar vortex intensification (VI) events https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JD006302

Overnight models back to warmer for late month.

25 degrees here, with a heavy frost. Coldest air mass since the end of February around these parts.

Simon's GEFS 35 day regime forecast does show some indications of a shallow regime change coinciding with the early part of December. In my opinion a temporary cold period such as the one currently might be in the cards. AO drops in the days ahead , possibly towards neutral, as the SPV remains strong well above the ERA5 mean.

Surprised they went with that snowfall prediction. Would speculate lower.

From Bluewave. Maybe a role with the NAO in my opinion Here is his post : Rapidly warming SSTs off our coast go together with the record 500mb ridging that we have been experiencing. https://climate.nasa.gov/news/2798/watery-heatwave-cooks-the-gulf-of-maine/ Most of us are familiar with heat waves on land, but in a warming world, heat waves are starting to become common in the ocean, too. One basin in particular, the normally cool Gulf of Maine in the Northwest Atlantic Ocean, has seen several heat waves in recent years and has spent most of 2018 with unusually warm water temperatures. On August 8, 2018, scientists using satellite data and sea-based sensors measured the second warmest sea surface temperatures ever observed in the Gulf of Maine. Average water temperatures reached 20.52 degrees Celsius (68.93 degrees Fahrenheit) that day, just 0.03°C (0.05°F) below the record set in 2012. The maps on this page show sea surface temperature anomalies as compiled by NOAA’s Coral Reef Watch, which blends observations from the Suomi NPP, MTSAT, Meteosat, and GOES satellites and from computer models. Shades of red and blue indicate how much water temperatures were above or below the long-term average for the region. The map above shows conditions on August 8, the near-record setting day, while the map below shows conditions across the entire month of August 2018. The heatwave of 2018 fits with a much longer trend in the region, which is among the fastest-warming parts of the global ocean. In the past three decades, the Gulf of Maine has warmed by 0.06°C (0.11°F) per year, three times faster than the global average. Over the past 15 years, the basin has warmed at seven times the global average. The Gulf has warmed faster than 99 percent of the global ocean. August 1 - 31, 2018 “We’ve set 10 daily temperature records this summer, after setting 18 this winter,” said Andrew Pershing, chief scientist of the Gulf of Maine Research Institute (GMRI). “We’ve had to add new colors to our temperature illustrations to reflect just how warm the Gulf of Maine has been this year.” In recent years, oceanographers have come to define marine heatwaves as periods when water temperature rise above the 90th percentile (of average temperatures) for more than five days. In 2018, the Gulf of Maine has spent more than 180 days above the 90th percentile. The Gulf of Maine stretches from Cape Cod to Nova Scotia, and it is key intersection between cold water masses from the Arctic and warm water masses from the Gulf Stream. The warming trend in this basin likely has two main causes. First is the overall warming of the global ocean as air temperatures and greenhouse gas concentrations rise. Second is the melting of ice in Greenland and the Arctic Ocean, which provides pulses of fresh water that can alter ocean circulation patterns in the region. “We are seeing a major shift in the circulation in the North Atlantic, likely related to a weakening Atlantic Meridional Overturning Circulation (AMOC),” said Pershing. “One of the side effects of a weaker AMOC is that the Gulf Stream shifts northward and the cold current flowing into the Gulf of Maine gets weaker. This means we get more warmer water pushing into the Gulf.” “Climate change is likely contributing to the circulation changes through melting in Greenland and the Arctic,” he added, “as well as making long-stretches of warm weather more likely.” The warming waters are already affecting marine species in the area, according to several news media and scientist accounts. Herring populations (based on fishing catches) seem to be down this year, and researchers and fishermen are seeing more species usually found in warmer waters, such as butterfish and squid. The populations of copepods, a key food source for endangered Northern Right Whales, also seem to be moving with the changing conditions. And puffins have had to adapt in feeding their chicks this year, as the newly common butterfish are too large for hatchlings to swallow.

Impressive + PMM Pretty classic +PMM Eric Webb @webberweather Despite being in a La Nina w/ subseasonal forcing solidly over the Indian Ocean, the subtropical jet will actually be quite active in late Nov thanks to a positive Pacific Meridional Mode (PMM) event buttressing moist convection in the tropical off-equatorial central Pacific. 4:11 AM · Nov 18, 2020

Yep, will be interesting to watch the progression. Meanwhile, MJVentrice @MJVentrice A strong Stratospheric Polar Vortex is supporting -80C temperatures at 10mb, which is slightly earlier than normal to see these cold of temperatures. 7:34 AM · Nov 18, 2020·Twitter Web App

Matches the Euro weeklies. Comfortable outside decorating weather.

NAM state still looks uneventful. Meanwhile World Climate Service @WorldClimateSvc Today's 46-day ECMWF shows a +4-5°C anomaly for the full month of December in the north-central USA (vs 20-year climatology). At face value that would rival the warmest Decembers on record in Minnesota, such as 2015 and 1997 - both super El Niño winters

Coldest reading so far this Fall at 34 degrees.

GFS having a hard time, ( but what is new ), honestly even the Euro last week was focusing on a -EPO cold air dump. That has changed now. EPS looks very warm for late November and early December. Afternoon BAMWx update :

Interesting, but I think Ben has his MJO phases a bit mixed up.

The same SST feedback issues that support a bad Pac are evident in the Atlantic. The Atlantic's huge rise in SST the last 3 years is the most meaningful and pronounced versus any other part of the globe to a large extent. The WAR is robust not only in the summer but even other seasons as well.

Latest

crazy......

We get our first freeze next week it appears. Avoided 3 freeze warnings so far in my local area.

Little faith in those indices. Many , many false attempts the last 24 months. Enjoy the outdoors late month.

What's new? Everyone on the warm and less snow bandwagon. Simple to see warmth is expanding and the climate is warming. We just broke into another historic anomalous precip event. The tropical jet is changing as well in response to warming. Dominos falling down one after another, rather sad.

Good points. I have noticed over time the CFSv2 trends to the GEFS.