bluewave

The multiyear ice for 2021 finished at the 2nd lowest behind 2012. So just looking at the extent rebound from 2020 can be a bit deceptive. The amount of MYI is one of the key indicators as to how much the Arctic has warmed. https://arctic.noaa.gov/Report-Card/Report-Card-2021/ArtMID/8022/ArticleID/945/Sea-Ice Sea ice age Sea ice drifts around the Arctic Ocean, forced by winds and ocean currents, growing and melting thermodynamically. Ice convergence can also lead to dynamic thickening (i.e., ridging and rafting) while ice divergence during winter exposes open water within which new ice can form. Age is a proxy for thickness as multiyear ice (ice that survives at least one summer melt season) grows thicker over successive winter periods. Age is here presented over the Arctic Ocean domain (Fig. 3, inset) for the period 1985-2021. In the week before the 2021 annual minimum extent, when the age values of the remaining sea ice are incremented by one year, the amount of multiyear ice remaining in the Arctic Ocean was the second lowest on record (above only 2012). The September multiyear sea ice extent declined from 4.40 million km2 in 1985 to 1.29 million km2 in 2021 (Fig. 3). Over the same period, the oldest ice (>4 years old) declined from 2.36 million km2 to 0.14 million km2. In the 37 years since records began in 1985, the Arctic Ocean has changed from a domain dominated by multiyear ice to one where first-year ice prevails. A younger ice cover implies a thinner, less voluminous ice pack.

We are back to the high temperatures beating guidance as the TPV retreats further NW with the more +AO pattern. February pattern so far January pattern

The TPV shifting closer to Greenland from Hudson Bay in January is allowing milder temperatures this month near the East Coast with the more +AO pattern.

A recent study found that the extreme drop in MYI coverage with the 2007 season has slowed the rate of new extent record minimums in September. The last record minimum extent in September occurred back in 2012. But we came close to that record a few years ago. The thinner ice makes it easier for the winds to push around the extents quite a bit from year to year. So we can have large differences between years like 2012 and 2013 and 2020 and 2021. The big story is that even the most favorable seasons since 2007 have never been able to approach early 2000s extents and volume levels. So it appears that the fundamental shift in the Arctic has already occurred back in 2007. While we’ll eventually surpass 2012 and head toward an ice free season in the future as the planet warms, 2007 may be more significant than the first technically ice free season below 1 million sq km. https://iopscience.iop.org/article/10.1088/1748-9326/aae3ec From the peak MYI coverage in 2002 to the end of our record in 2017, the Arctic has lost more than 2 × 106 km2, a decrease of 50%; MYI now covers less than one-third of the Arctic Ocean. As with ice volume, the largest decline in MYI coverage followed the record-setting end-of-summer ice extent in 2007. In addition to annual ice export, recent losses of MYI are due to melt of MYI advected into the southern Beaufort Sea from the north coast of Greenland and the CAA, the source region of the thickest and most deformed ice in the Arctic Ocean. https://climate.nasa.gov/news/2817/with-thick-ice-gone-arctic-sea-ice-changes-more-slowly/ The Arctic Ocean's blanket of sea ice has changed since 1958 from predominantly older, thicker ice to mostly younger, thinner ice, according to new research published by NASA scientist Ron Kwok of the Jet Propulsion Laboratory, Pasadena, California. With so little thick, old ice left, the rate of decrease in ice thickness has slowed. New ice grows faster but is more vulnerable to weather and wind, so ice thickness is now more variable, rather than dominated by the effect of global warming. Working from a combination of satellite records and declassified submarine sonar data, NASA scientists have constructed a 60-year record of Arctic sea ice thickness. Right now, Arctic sea ice is the youngest and thinnest its been since we started keeping records. More than 70 percent of Arctic sea ice is now seasonal, which means it grows in the winter and melts in the summer, but doesn't last from year to year. This seasonal ice melts faster and breaks up easier, making it much more susceptible to wind and atmospheric conditions. Kwok's research, published today in the journal Environmental Research Letters, combined decades of declassified U.S. Navy submarine measurements with more recent data from four satellites to create the 60-year record of changes in Arctic sea ice thickness. He found that since 1958, Arctic ice cover has lost about two-thirds of its thickness, as averaged across the Arctic at the end of summer. Older ice has shrunk in area by almost 800,000 square miles (more than 2 million square kilometers). Today, 70 percent of the ice cover consists of ice that forms and melts within a single year, which scientists call seasonal ice. Sea ice of any age is frozen ocean water. However, as sea ice survives through several melt seasons, its characteristics change. Multiyear ice is thicker, stronger and rougher than seasonal ice. It is much less salty than seasonal ice; Arctic explorers used it as drinking water. Satellite sensors observe enough of these differences that scientists can use spaceborne data to distinguish between the two types of ice. Thinner, weaker seasonal ice is innately more vulnerable to weather than thick, multiyear ice. It can be pushed around more easily by wind, as happened in the summer of 2013. During that time, prevailing winds piled up the ice cover against coastlines, which made the ice cover thicker for months. The ice's vulnerability may also be demonstrated by the increased variation in Arctic sea ice thickness and extent from year to year over the last decade. In the past, sea ice rarely melted in the Arctic Ocean. Each year, some multiyear ice flowed out of the ocean into the East Greenland Sea and melted there, and some ice grew thick enough to survive the melt season and become multiyear ice. As air temperatures in the polar regions have warmed in recent decades, however, large amounts of multiyear ice now melt within the Arctic Ocean itself. Far less seasonal ice now thickens enough over the winter to survive the summer. As a result, not only is there less ice overall, but the proportions of multiyear ice to seasonal ice have also changed in favor of the young ice. Seasonal ice now grows to a depth of about six feet (two meters) in winter, and most of it melts in summer. That basic pattern is likely to continue, Kwok said. "The thickness and coverage in the Arctic are now dominated by the growth, melting and deformation of seasonal ice." The increase in seasonal ice also means record-breaking changes in ice cover such as those of the 1990s and 2000s are likely to be less common, Kwok noted. In fact, there has not been a new record sea ice minimum since 2012, despite years of warm weather in the Arctic. "We've lost so much of the thick ice that changes in thickness are going to be slower due to the different behavior of this ice type," Kwok said. Kwok used data from U.S. Navy submarine sonars from 1958 to 2000; satellite altimeters on NASA's ICESat and the European CryoSat-2, which span from 2003 to 2018; and scatterometer measurements from NASA's QuikSCAT and the European ASCAT from 1999 to 2017.

All the models have been too fast with the forcing changes going back to December. The convection has been stalling in place acting more like a standing wave. So the pattern change they were forecasting near the solstice got pushed back to January. Then they were too fast to weaken the January +PNA which is now continuing into February. The other thing is that the MJO has been competing with forcing in other locations. This month we have split forcing in the IO and WPAC at the same time. So we aren’t getting the typical MJO forcing response. That being said, the late February forecast will probably come down to whether we keep the split forcing or it consolidates more near the Maritime Continent. Split forcing pattern in IO and WPAC

The EPS is identical to the GEPS at day 15. The GEFS is on its own. The main difference between the GEPS and GEFS is the tropical convection. The GEFS is slower moving the forcing east from the IO than the GEPS. So the GEPS and EPS have more of a -PNA in late February with the convection closer to the Maritime Continent.

The time to watch for snow potential here will be next week following the record 582 DM West Coast heat dome in California. Then we get another big amplification and the trough begins to pull back to the Plains. But as usual, the storm details will come down to the short term forecasts.

The Ridiculously Resilient Ridge continues to make headlines.

This was the first time that we ever had a +PNA January with a PDO value lower than -2.00. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table Jan 2022 PDO….-2.42 PNA…..+1.01 Jan 2000 PDO…-2.20 PNA….-0.82 Jan 1972 PDO…-2.12 PNA…-1.41 Jan 1956 PDO….-2.26 PNA….-1.32 Jan 1952 PDO…-2.19 PNA…-1.98

Hard to know any details for the day 8-10 period. But the EPS and GEPS have an impressive +300 to +400 meter 500 mb height anomaly just off the West Coast. So a general storm signal exists in mid-February.

We didn’t have the big gap between snowstorms this year that we had last year. Our January snowstorms were only 3 weeks apart. Last year we had a big intermission between the mid-December and early February events. So another period to watch for snow in mid-February would only be a little over 2 weeks later than our last snow on the 29th.

Yeah, ISP has averaged around 40” since 2010. Newark is running closer to 35”. It’s been the best era for snowstorms tracking near the benchmark which favors Long Island. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.0 0.7 5.4 15.4 11.8 6.8 0.4 40.0 2021-2022 0.0 T 0.3 31.8 0.2 M M 32.3 2020-2021 T 0.0 7.5 1.1 24.9 T T 33.5 2019-2020 0.0 0.1 4.2 2.5 0.0 T T 6.8 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 12.8 2017-2018 0.0 T 6.0 22.0 1.4 31.9 4.6 65.9 2016-2017 T T 3.2 14.0 14.7 7.4 T 39.3 2015-2016 0.0 0.0 T 24.8 13.2 3.2 0.2 41.4 2014-2015 0.0 T 0.4 30.2 13.4 19.7 0.0 63.7 2013-2014 0.0 0.3 8.1 25.2 24.5 5.4 0.2 63.7 2012-2013 0.0 4.2 0.6 3.3 31.4 7.4 0.0 46.9 2011-2012 0.3 0.0 T 3.8 0.6 T 0.0 4.7 2010-2011 0.0 T 14.9 34.4 3.9 2.1 T 55.3 2009-2010 0.0 0.0 25.3 6.4 21.7 0.4 0.0 53.8 Monthly Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.4 1.1 5.9 11.2 11.1 5.1 0.5 34.9 2021-2022 0.0 0.1 0.1 14.6 0.1 M M 14.9 2020-2021 T 0.0 11.9 3.2 30.6 T 0.0 45.7 2019-2020 0.0 T 4.2 2.7 T T T 6.9 2018-2019 0.0 6.4 T 0.9 4.8 9.9 0.0 22.0 2017-2018 0.0 T 7.7 10.1 3.4 13.2 5.0 39.4 2016-2017 0.0 T 3.4 9.3 7.9 9.4 0.0 30.0 2015-2016 0.0 0.0 0.3 25.7 5.2 1.6 T 32.8 2014-2015 T 1.4 0.3 14.9 13.5 16.3 T 46.4 2013-2014 0.0 T 9.4 20.8 30.3 0.2 0.4 61.1 2012-2013 0.0 6.6 1.9 1.4 10.8 8.8 0.0 29.5 2011-2012 5.2 0.0 0.0 3.3 0.3 0.0 0.0 8.8 2010-2011 0.0 T 24.5 37.4 4.1 2.2 T 68.2 2009-2010 0.0 0.0 13.3 1.7 32.9 T 0.0 47.9

This year the heaviest snows have shifted back to the east. Last several seasons it was more west. So a continuation of the multi-year windshield wiper effect between ISP and EWR. Time Series Summary for ISLIP-NEWARK Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall ISP Total snowfall EWR 2022-04-30 32.3 14.9 2021-04-30 33.5 45.7 2020-04-30 6.8 6.9 2019-04-30 12.8 22.0 2018-04-30 65.9 39.0 2017-04-30 39.3 39.0 2016-04-30 41.4 32.8 2015-04-30 63.7 46.4 2014-04-30 63.7 61.1 2013-04-30 46.9 29.5 2012-04-30 4.7 8.8 2011-04-30 55.3 68.2 2010-04-30 53.8 47.9

I guess we are lucky that there hasn’t been a further south version of Jan 98 closer to our northern zones. https://www.weather.gov/media/btv/events/IceStorm1998.pdf This storm had historic impacts across northern New York, northern New England and southeast Canada due to the prolonged duration of the event (both meteorological and recovery period) and the magnitude of ice accretion and precipitation amounts. The most famous meteorological aspect of this storm was the devastating and destructive ice accumulation of more than 3 inches (75mm) in portions of northern New York and southeast Canada, with heavy ice accumulation across northern New England as well. Another major aspect of this storm was the extremely heavy precipitation across the region, including over 5 inches of rain that caused major flooding in portions of western New York.

Yeah, it’s always rough when areas that are heavily wooded get that much ice. The Long Beach area didn’t have any major power outages in Jan 94 with .5 to .75 of radial ice. We just don’t have that many tall trees near the beach. While the SPC HREF Fram had a cold bias south of 287, it really honed in on those hard hit interior areas with the blue .5+ of ice from the 12z Thursday forecast.

The GFS was the only model that really struggled with its cold bias. All the other guidance had the most icing up toward Ulster and Orange Counties. The NYC and Long Island areas generally need the cold to be in place when the freezing rain begins for significant icing build up on trees and power lines. Models were signaling for days that we would start out in the 40s and 50s with rain before any changeover. Past major icing events near the coast generally began with the temperatures below freezing.

Yeah, you can see the competing influences of the IO and PAC tropical forcing so far this month. We finally made it into the 50s yesterday for the first time in a month. So the extended cold pattern of January is beginning to shift to more of a back and forth temperature regime. Colder this weekend before we go back into the 40s next week. Then another cool down mid-February. The big question Is what happens in late February. It will all come down to where the forcing consolidates. If the IO forcing takes over, then it could get quite warm as the SE Ridge would be favored. But if the forcing can linger from the WPAC to CP, then a continuation of the back and forth temperature pattern.

The EPS has more of a -PNA look near the end of the 0z run. But the GEPS and GEFS not as much. The big story this winter was the historic PNA rise from December to January. It was the greatest on record from December to January. So even if the +PNA weakens or reverses in late February, the February PNA reading won’t be anything like December was. So in two consecutive La Niña winters, this December will be the only severe -PNA out of 6 winter months. The December PNA was a record breaking -2.56 and January jumped to +1.01.

Finally dropped to 31° here in SW Suffolk but rain still not freezing yet.

The leading edge of the cold air was very shallow so the higher terrain outside the immediate Hudson Valley slowed the advance.

33 here in SW Suffolk with moderate rain.

Yeah, extremes have become the new normal around here.

We got lucky that the impressive SPV never really coupled with the lower atmosphere. Plus we had the strong +PNA and -EPO to compensate. So even if there is a reversal like weeklies have, it’s uncertain how much would propagate down to the troposphere.

Last February was an outlier for us on extended snow cover. This winter so far is like other recent years with quick warm ups and snowmelt. While we had an increase in snowfall since 1981, the snow cover days haven’t kept up.

The whole FV3 upgrade process seems to be very bumpy. The GFS initially had the January 3rd heavy snow event in ACY further north up into our area. Then we saw it too far to the east with the blizzard last weekend. It seems that some forecast outlets held off on the snow forecast until they saw the GFS coming back NW. So this adds an unnecessary layer of confusion to the forecast process. It also raises the question of what will happen once the NAM is discontinued. Its already been 5 years since the last NAM upgrade and it’s showing with other models like the improving RGEM jumping around less than the NAM from run to run. It would be even more confusing if a FV3 NAM replacement introduces a whole new set of biases that complicate the forecast process. We are getting to the point where it seems better to rely more on the GEM, RGEM, and Euro. Sometimes the HREF and HRRR does well. But even they have their issues at times.