4 minutes ago, frd said:

 

Have you done any research on the summers that follow winters similar to this one bluewave? 

 

The default summer pattern since 2010 has been above normal to record warmth and dewpoints. But the specific details this year look pretty complex. We currently have one strongest +AO patterns on record. Does this continue or reverse in time for the summer? The Niña -like ridge north of Hawaii has flipped the -PDO to most negative in years. Will this continue or can the El Niño try to come on to counter that Pacific pattern? Plenty of mixed signals going into the spring.

21 hours ago, Allsnow said:

We would have the mjo briefly in the cold phases and the -epo ridge further East. I don’t think it’s lasts long but perhaps we pull a March 2019 like weekend.

We would definitely need some help from the -EPO/+PNA as that Atlantic vortex is on steroids. Maybe the current SOI drop and +AAM spike could help out in this regard.

Current SOI

19 minutes ago, CPcantmeasuresnow said:

Only made it to 5.1° so not even close. Looks like this will be the first season since I've been keeping temperature records that we don't go below zero. Just wondered if anyone has records in the HV as to the last season we didn't get below zero?

Just saw Bluewaves post above from Poughkeepsie records . Looking at those records it sees like 2007/08 was the last season I didn't get below zero. Another indicator of how absurd the temperatures have been since late December.

Seems like the records closer your area only go back to 1998.

4 hours ago, CPcantmeasuresnow said:

Currently 6.1, sub zero does not look like it’s happening tonight. In this pattern we may not get another shot at it this season. I can’t even remember the last year we didn’t go below zero. It’s been a long time.  

The only long term records for SE interior NY appear to be POU. Looks like the last time the seasonal minimum was this high was back in 1998.
 

At least we can brag that we got some small El Niño-like element to the pattern. The coldest temperature of the season often comes in February during an El Niño. The low of 14 in NYC is officially the coldest of the season. The last time this occurred was was with the super El Niño in 2016 and weaker one in 2015.

Coldest temperature season in NYC

Models are indicating another Niño-like +AAM rise near the end of February and start of March. While it is a warm pattern in late January like we recently experienced, it can offer a +PNA  near the start of March. So this may be our last shot a getting a small snow event to close out the season. But there may not be any guarantees since it will still be combined with the lingering Niña-like Pacific background pattern. 
 

Models really dry things out over the next 10 days with high pressure dominating. Only 1 cutter showing up for next Tuesday. It will be a nice break from all the clouds and showers during the first half of the month. 
 

57 minutes ago, CPcantmeasuresnow said:

It's getting difficult to even bother to look each morning. Why should I start out my day just affirming the  obvious and getting depressed. This isn't going away.

I guess some small  good news is that expectations were lowered well in advance. The very unfavorable Pacific pattern began last winter. Even though the first 3 weeks of December were a little colder than average, the hostile Pacific showed its cards early. The same pattern repeated in early December as all last winter. Cutter and hugger storm tracks lead to the heaviest snows ending up over the interior sections relative to the NYC area. Once the pattern warmed up after December 20th, we experienced one of the most unfavorable MJO, +AO, and +EPO patterns of all-time.

Several stations just recorded their warmest first 13 days of February on record. Places like Newark beat 1990. I guess it’s fitting since the +AO recently topped the previous all-time record set in February 1990.

Another jet stream record.

1 hour ago, mikem81 said:

you realize the 2016 number is extremely misleading.....most of it was one 30 incher...

What difference does that make for total snowfall over the period? There was also an additional 8.1” at JFK during the first 15 days of February. Some areas picked up 10”+ with the 2-5-16 storm.

PLAINVIEW             10.5   110 PM  2/05  TRAINED SPOTTER

We went from the highest 1/20 -2/12 snowfall to the lowest in just 4 years.

11 minutes ago, SnoSki14 said:

The AO could hit +6 or better again after just breaking that record 2 days ago.

The north Atlantic system will likely be sub 920mb (record is 914mb) and if that AO is any indication then they'll be more severely low pressure storms in the near future. 

Iceland and NW Europe are gonna take a lot of beatings. 

One extreme after another.

Mass melting of the West Antarctic Ice Sheet was a major cause of high sea levels during a period known as the Last Interglacial (129,000-116,000 years ago), an international team of scientists led by UNSW’s Chris Turney has found. The research was published today in Proceedings of the National Academy of Sciences (PNAS).
 
The extreme ice loss caused a multi-metre rise in global mean sea levels – and it took less than 2˚C of ocean warming for it to occur. 

“Not only did we lose a lot of the West Antarctic Ice Sheet, but this happened very early during the Last Interglacial,” says Chris Turney, Professor in Earth and Climate Science at UNSW Sydney and lead author of the study. 

Fine layers of ancient volcanic ash in the ice helped the team pinpoint when the mass melting took place. Alarmingly, the results indicated that most ice loss occurred within the first millennia, showing how sensitive the Antarctic is to higher temperatures. 

“The melting was likely caused by less than 2°C ocean warming – and that's something that has major implications for the future, given the ocean temperature increase and West Antarctic melting that’s happening today,” Professor Turney says. 

During the Last Interglacial, polar ocean temperatures were likely less than 2˚C warmer than today, making it a useful period to study how future global warming might affect ice dynamics and sea levels. 

“This study shows that we would lose most of the West Antarctic Ice Sheet in a warmer world,” says Professor Turney. 

In contrast to the East Antarctic Ice Sheet – which mostly sits on high ground – the West Antarctic sheet rests on the seabed. It’s fringed by large areas of floating ice, called ice shelves, that protect the central part of the sheet. 

As warmer ocean water travels into cavities beneath the ice shelves, ice melts from below, thinning the shelves and making the central ice sheet highly vulnerable to warming ocean temperatures. 

Blue ice areas are created by fierce, high-density winds that remove the top layer of snow and erode the exposed ice. As the ice is removed, ancient ice flows up to the surface, offering an insight into the ice sheet's history. Image: AntarcticScience.cm

Going back in time

To undertake their research, Professor Turney and his team travelled to the Patriot Hills Blue Ice Area, a site located at the periphery of the West Antarctic Ice Sheet, with support from Antarctic Logistics and Expeditions (or ALE). 

Blue ice areas are the perfect laboratory for scientists due to their unique topography – they are created by fierce, high-density katabatic winds. When these winds blow over mountains, they remove the top layer of snow and erode the exposed ice. As the ice is removed, ancient ice flows up to the surface, offering an insight into the ice sheet’s history.

While most Antarctic researchers drill down into the ice core to extract their samples, this team used a different method – horizontal ice core analysis.  

“Instead of drilling kilometres into the ice, we can simply walk across a blue ice area and travel back through millennia. By taking samples of ice from the surface we are able to reconstruct what happened to this precious environment in the past,” Professor Turney says.

Through isotope measurements, the team discovered a gap in the ice sheet record immediately prior to the Last Interglacial. This period of missing ice coincides with the extreme sea level increase, suggesting rapid ice loss from the West Antarctic Ice Sheet. The volcanic ash, trace gas samples and ancient DNA from bacteria trapped in the ice all support this finding.

Trace gas bubbles in the ice samples. Image: AntarcticScience.com

Learning from the Last Interglacial 

Ice age cycles occur approximately every 100,000 years due to subtle changes in Earth’s orbit around the Sun. These ice ages are separated by warm interglacial periods. The Last Interglacial is the most recent warm period to our current interglacial period, the Holocene.

While human contribution to global warming makes the Holocene unique, the Last Interglacial remains a useful research point to understand how the planet responds to extreme change. 

“The future is heading far beyond the range of anything we've seen observed in the scientific instrumental record of the last 150 years,” says Professor Turney. “We have to look further into the past if we’re going to manage future changes.” 

During the Last Interglacial, global mean sea levels were between 6m and 9m higher than present day, although some scientists suspect this could have reached 11m. 

The sea level rise in the Last Interglacial can’t be fully explained by the Greenland Ice Sheet melt, which accounted for a 2m increase, or ocean expansion from warmer temperatures and melting mountain glaciers, which are thought to have caused less than a 1m increase.

“We now have some of the first major evidence that West Antarctica melted and drove a large part of this sea level rise,” says Professor Turney.

An urgent need to minimise future warming

The severity of the ice loss suggests that the West Antarctic Ice Sheet is highly sensitive to future ocean warming.

“The West Antarctic Ice Sheet is sitting in water, and today this water is getting warmer and warmer,” says Professor Turney, who is also a Chief Investigator of the ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH). 

Using data gained from their fieldwork, the team ran model simulations to investigate how warming might affect the floating ice shelves. These shelves currently buttress the ice sheets and help slow the flow of ice off the continent. 

The results suggest a 3.8m sea level rise during the first thousand years of a 2˚C warmer ocean. Most of the modelled sea level rise occurred after the loss of the ice shelves, which collapsed within the first two hundred years of higher temperatures. 

The researchers are concerned that persistent high sea surface temperatures would prompt the East Antarctic Ice Sheet to melt, driving global sea levels even higher.

“The positive feedbacks between a warming ocean, ice shelf collapse, and ice sheet melt suggests that the West Antarctic may be vulnerable to passing a tipping point,” stressed Dr Zoë Thomas, co-author and ARC Discovery Early Career Research Award (DECRA) Fellow at UNSW.

Professor Chris Turney drilling for ice in the Patriot Hills area. Image: AntarcticScience.com

“As it reaches the tipping point, only a small increase in temperature could trigger abrupt ice sheet melt and a multi-metre rise in global sea level.”

At present, the consensus of the Intergovernmental Panel on Climate Change (IPCC) 2013 report suggests that global sea level will rise between 40cm and 80cm over the next century, with Antarctica only contributing around 5cm of this. 

The researchers are concerned that Antarctica’s contribution could be much greater than this.

“Recent projections suggest that the Antarctic contribution may be up to ten times higher than the IPCC forecast, which is deeply worrying,” says Professor Christopher Fogwill, co-author and Director of The Institute for Sustainable Futures at the UK University of Keele.

“Our study highlights that the Antarctic Ice Sheet may lie close to a tipping point, which once passed may commit us to rapid sea level rise for millennia to come. This underlines the urgent need to reduce and control greenhouse gas emissions that are driving warming today.” 

Notably, the researchers warn that this tipping point may be closer than we think.

“The Paris Climate Agreement commits to restricting global warming to 2˚C, ideally 1.5˚C, this century,” says Professor Turney.   

“Our findings show that we don’t want to get close to 2˚C warming.” 

Professor Turney and his team hope to expand the research to confirm just how quickly the West Antarctic Ice Sheet responded to warming and which areas were first affected.

“We only tested one location, so we don’t know whether it was the first sector of Antarctica that melted, or whether it melted relatively late. How these changes in Antarctica impacted the rest of the world remains a huge unknown as the planet warms into the future” he says. 

“Testing other locations will give us a better idea for the areas we really need to monitor as the planet continues to warm.”

Here comes the next big extreme. No let up in sight for this raging +AO/+NAO pattern.

It will be interesting to see how close this gets to the record.

https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.2097

The Braer storm of January 1993 was the deepest ever recorded cyclone outside of the Tropics with a minimum core pressure of 914mbar, but due to its track between Scotland and Iceland it caused little damage and was never intensively examined. Here we present a study of the dynamics of the storm using modern re‐analysis data from the European Centre for Medium‐Range Weather Forecasts (ECMWF) and sensitivity studies with the Weather Research and Forecasting (WRF) model to quantify influences of diabatic heating and Greenland's topography on the track and rapid deepening of the storm.

1 hour ago, LibertyBell said:

any idea on whats causing the AO to be so strong?

There has been some research that the IOD could possibly impact the NAO and AO. Maybe the record +IOD from November into December was in some way responsible. Some of our other extremely +AO +NAO events were preceded by strong MJO 2-3 forcing. It could be that the IO standing wave from November into mid-December played a role. But we’ll  probably need a a study to confirm.

https://journals.ametsoc.org/doi/10.1175/JCLI3577.1?mobileUi=0&

The dominant pattern of atmospheric variability in the North Atlantic sector is the North Atlantic Oscillation (NAO). Since the 1970s the NAO has been well characterized by a trend toward its positive phase. Recent atmospheric general circulation model studies have linked this trend to a progressive warming of the Indian Ocean. Unfortunately, a clear mechanism responsible for the change of the NAO could not be given. This study provides further details of the NAO response to Indian Ocean sea surface temperature (SST) anomalies. This is done by conducting experiments with a coupled ocean–atmosphere general circulation model (OAGCM). The authors develop a hypothesis of how the Indian Ocean impacts the NAO.

By analyzing model simulations we found that the South Asian jet can act as a waveguide with circumglobal teleconnection in the Northern Hemisphere. The meridional wind pattern, associated with this circumglobal teleconnection, is connected with the North Atlantic Oscillation. A warming/cooling in the Indian Ocean, especially in the western Indian Ocean, produces anomalies in the South Asian jet. The waveguiding effect of the South Asian jet carries the perturbation into the North Atlantic sector and leads to a NAO-like response.

The observed recent positive trend in the NAO has likely contributions from the observed warming in the Indian Ocean. Our analysis—confirmed by the observed trend in the western South Asian jet and the anomaly pattern of the 300-hPa winter meridional wind—indicates that the change of the NAO may be via the circumglobal pattern.

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0502.1?mobileUi=0

The teleconnection patterns associated with phases 3 and 7 are also important for Atlantic blocking. In agreement with Lin et al. (2009) and Cassou (2008), 10–15 days after MJO phase 3 a positive NAO pattern develops over the Atlantic. We find that Atlantic blocking frequency is more than halved in association with the positive NAO pattern. In contrast, MJO phase 7 is followed by a negative NAO pattern, which coincides with a high-amplitude wavelike flow and an increase in blocking frequency. Atlantic blocking frequency is almost doubled following phase 7, reaching +16.5% relative to climatology. Approximately 14%–15% of all DJF Atlantic blocked days follow phase 7.

17 minutes ago, kat5hurricane said:

I think it was @bluewave who posted that the city hasn't dipped below 20 since December 19th. That's a remarkable stat to go 2 months in the middle of winter with zero below 20 readings. Has that ever happened in a 2 month winter span? Even '97-'98 and '11-'12 had a few cold spells I believe.

This is the first time since 31-32. Even 01-02 dropped to 19 degrees from 12-20 to 02-12.

Very odd to have to be concerned about a hard freeze in February with such an early bloom.

It’s good to finally see the sun.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=45&network=NY_ASOS&zstation=ISP&hour=12&year=2020&month=2&dpi=100&_fmt=png

33 minutes ago, Allsnow said:

Yeah, we had a snowy 1st weekend of March with that -epo. 

Yeah, the EPO actually flipped negative last winter in late January. But it took until early March to produce the snowfall. That’s when the -PNA finally relaxed.  But this winter we have seen one of the most extreme +EPO/+AO patterns of all-time. 

16 minutes ago, kat5hurricane said:

March 2018 was the last time I can remember a pattern flipping on a dime and that was due to a historic SSW event as far as I recall.

That one actually began with the start warming event on February 10th. But it took about 3 weeks to flip the pattern for us. In the mean time we had the record 80 degree warmth. Last March we got lucky when the -EPO developed.

2 minutes ago, kat5hurricane said:

Not really. We've been in this "stuck" pattern regime for years. Rarely do we see complete pattern flips anymore.

Yeah, stuck weather patterns have become the new normal. We can remember the record -NAO pattern from May to October in 2019. Constant 50/50 lows and backdoor cold fronts. 

1 hour ago, snowman19 said:

@Allsnow @bluewave A +4 sigma NAM index on the last week of February....I think we’re cooked into early March and at that point, you really only have the first 15 days to make something happen:  https://twitter.com/SimonLeeWx/status/1227541123155005441?s=20 

Other than a brief Arctic shot on Saturday, all the cold continues to remain locked up over Alaska and Greenland. This has been the pattern since December 22nd. We continue to see the record +AO pattern extend right into late February. On the Pacific side, we are seeing the most extreme +EPO since 2012.
 

This was a controversial decision when it was made in 2016.

https://blogs.agu.org/wildwildscience/2016/07/28/noaa-makes-decision-new-global-weather-model-controversy-likely/

NOAA has decided on the nuts and bolts of a new, next generation, weather model that will replace the present Global Forecast System (GFS model), and the choice is sure to spark some controversy. The choice boiled down to a system called MPAS vs FV3. Many meteorologists were rooting for MPAS, which was developed by NCAR, while NOAA was leaning toward the FV3 which was a project of the GFDL Lab. 

Dr. Cliff Mass (at the Univ. of Washington) has written several blog posts about how we have fallen behind in numerical weather modelling, and has been championing the MPAS system as the much better way forward. It looks like this will not happen, based on news I just heard about tonight. NOAA chose the FV3 today, instead of MPAS (The video above shows the FV3 in action) and I am anxious to hear the debate that will soon ensue. 

There are two sides to this issue, and smart people have different opinions on both sides, and NOAA’s press release ishere. I’ve asked Cliff Mass for a comment, and will update this post when new info arrives. NOAA folks, and others, who favor the FV3 core, I would love to share your views as well.