bluewave

Another jet stream record.

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 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Jan 20 to Feb 15 Missing Count 1 2016-02-15 38.7 0 2 1961-02-15 33.4 0 3 2014-02-15 27.8 0 4 1978-02-15 27.2 0 5 1983-02-15 24.7 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Jan 20 to Feb 15 Missing Count 1 2020-02-15 0.0 3 2 1981-02-15 T 0 - 1980-02-15 T 0

We went from the highest 1/20 -2/12 snowfall to the lowest in just 4 years. Time Series Summary for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Jan 20 to Feb 12 Missing Count 1 2020-02-12 0.0 0 2 1981-02-12 T 0 - 1980-02-12 T 0 - 1960-02-12 T 0 Time Series Summary for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Jan 20 to Feb 12 Missing Count 1 2016-02-12 32.3 0 2 1961-02-12 28.5 0 3 1983-02-12 26.4 0 4 1994-02-12 25.8 0 5 2006-02-12 25.4 0

One extreme after another.

Ancient Antarctic ice melt increased sea levels by 3+ metres – and it could happen again Twitter Facebook LinkedIn 12 FEB 2020 SHERRY LANDOW Rising ocean temperatures drove the melting of Antarctic ice sheets and caused extreme sea level rise more than 100,000 years ago, a new international study led by UNSW Sydney shows. https://newsroom.unsw.edu.au/news/science-tech/ancient-antarctic-ice-melt-increased-sea-levels-3-metres-–-and-it-could-happen 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.

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.

This is the first time since 31-32. Even 01-02 dropped to 19 degrees from 12-20 to 02-12. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Lowest Min Temperature Dec 20 to Feb 12 Missing Count 1 1932-02-12 21 0 2 2020-02-12 20 1 3 2002-02-12 19 0

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

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.

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.

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.

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.

Imagine living an a place where you could have almost 100” of snow to date during your 4th warmest winter. Time Series Summary for Caribou Area, ME (ThreadEx) - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2015-2016 21.6 0 2 2009-2010 21.0 0 3 2001-2002 19.3 0 4 2019-2020 18.2 19 5 1959-1960 17.7 0 Time Series Summary for Caribou Area, ME (ThreadEx) - Oct through Sep Click column heading to sort ascending, click again to sort descending. Season Total Snowfall Missing Count 2019-2020 92.8 233

That -560 meter 500 mb height anomaly on the EPS looks close to the record lowest for the North Atlantic.

Euro has twin 928 mb lows.

Last time that NYC dropped below 20 degrees was December 19th. Brief cool down with temperatures reaching 50 or warmer a few days before and after.

More quick flights coming up.

It’s one storm system after another with this supercharged jet stream pattern. Another 200 kt jet max coming up. Numerous maxes in the 4 to 5 sd range this winter. January 25th was my last heavy rain storm since December. But a ton of small and medium rainfall events.

Hopefully, this cold bias gets fixed before next winter. We knew this last winter while the FV3 was the parallel before it became operational. https://www.wired.com/story/the-governments-new-weather-model-faces-a-storm-of-protest/ The government’s new weather forecast model has a slight problem: It predicts that outside temperatures will be a few degrees colder than what nature delivers. This “cold bias” means that local meteorologists are abandoning the National Weather Service in favor of forecasts produced by British and European weather agencies. For the past few weeks, the National Weather Service has been forecasting snowfall that ends up disappearing, according to Doug Kammerer, chief meteorologist at WRC-TV in Washington, DC. “It’s just not performing well,” Kammerer says. “It has continued to show us getting big-time snowstorms in this area, where the European model will not show it.” https://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

9 days in February with at least a T of rain so far. But not much total rainfall to show for it. We can remember the heavier rainfall forecasts for last Friday got lighter the close in we got. Welcome to Seattle. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Precipitation 2020-02-01 T 2020-02-02 0.07 2020-02-03 T 2020-02-04 T 2020-02-05 T 2020-02-06 0.51 2020-02-07 0.25 2020-02-08 0.00 2020-02-09 0.00 2020-02-10 0.37 2020-02-11 0.31

NYC is currently tied with 16-17 for 6th warmest winter so far. Snowfall ranks in 9th lowest so far for the DJF met winter period. This is a little ahead of last winter which finished 7th lowest. The full seasonal snowfall from fall to spring is currently 4th lowest. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2001-2002 41.6 0 2 2015-2016 41.0 0 3 2011-2012 40.5 0 4 1931-1932 40.2 0 5 1997-1998 39.6 0 6 2019-2020 39.3 19 - 2016-2017 39.3 0 7 1990-1991 39.1 0 8 1998-1999 38.6 0 9 1948-1949 38.5 0 10 1889-1890 38.4 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Total Snowfall Missing Count 1 1997-1998 0.5 0 2 1918-1919 1.1 0 3 1972-1973 2.6 0 4 1931-1932 2.7 0 5 1991-1992 3.2 0 6 2001-2002 3.5 0 7 2018-2019 3.7 0 8 2011-2012 4.5 0 9 2019-2020 4.8 19 10 1989-1990 5.0 0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1973-04-30 2.8 0 2 2002-04-30 3.5 0 3 1919-04-30 3.8 0 4 2020-04-30 4.8 81 5 1901-04-30 5.1 2 6 1932-04-30 5.3 0 7 1998-04-30 5.5 0 8 2012-04-30 7.4 0 9 1989-04-30 8.1 0 - 1878-04-30 8.1 0 10 1951-04-30 9.3 0