bluewave

The blizzard is occurring around the heaviest snowfall dates of the season since the 09-10. ISP snowiest dates since 09-10 12-14…6.3 12-16…5.8 12-19…9.6 12-20…14.3 12-26….11.3 1-2……..7.8 1-3……..8.6 1-4…….16.0 1-7…….16.8 1-12…..14.0 1-21…..18.6 1-23….23.4 1-26….11.6 1-27…..27.0 1-30….5.9 2-1……11.1 2-2….5.9 2-3….11.6 2-5….12.9 2.7…..6.5 2-8….19.6 2-9….26.8 2-10….9.2 2-13….8.3 2-18….6.0 2-21…5.8 2-26…9.5 3-1…..9.6 3-2….11.5 3-5….6.4 3-7…..8.5 3-13….6.4 3-20….5.9 3-21….18.5

This is our next one coming right at the peak period for heavy snow events since the 09-10 winter.

The -PNA warm up next week matches La Niña climo for February. But the quick +PNA return goes off script. This winter continues to do its own thing. A +PNA La Niña February is very rare. But so was such an extreme record -PNA December. So who knows anymore with this more extreme climate.

The next several runs will be decisive. But even the runs 24hrs before the January 2000 event were way off. Tiny initialization errors throw the models off. https://journals.ametsoc.org/view/journals/mwre/130/4/1520-0493_2002_130_0957_icsaeg_2.0.co_2.xml Short- and medium-range (24–96-h) forecasts of the January 2000 U.S. east coast cyclone and associated snowstorm are examined using the U.S. Navy global forecast model and adjoint system. Attention is given to errors on the synoptic scale, including forecast position and central pressure of the cyclone at the verification time of 1200 UTC 25 January 2000. There is a substantial loss of predictive skill in the 72- and 96-h forecasts, while the 24- and 48-h forecasts capture the synoptic-scale features of the cyclone development with moderate errors. Sensitivity information from the adjoint model suggests that the initial conditions for the 72-h forecast starting at 1200 UTC 22 January 2000 contained relatively small, but critical, errors in upper-air wind and temperature over a large upstream area, including part of the eastern Pacific and “well observed” areas of western and central North America. The rapid growth of these initial errors in a highly unstable flow regime (large singular-vector growth factors) is the most likely cause of the large errors that developed in operational short- and medium-range forecasts of the snowstorm. The large extent of the upstream sensitive area in this case would appear to make “targeting” a small set of new observations an impractical method to improve forecast skill. A diagnostic correction (derived from adjoint sensitivity information) of a part of the initial condition error in the 72-h forecast reduces the forecast error norm by 75% and improves a 1860-km error in cyclone position to a 105-km error. This demonstrates that the model is capable of making a skillful forecast starting from an initial state that is plausible and not far from the original initial conditions. It is also shown that forecast errors in this case propagate at speeds that are greater than those of the synoptic-scale trough and ridge features of the cyclone.

Better data assimilation closer to storm time.

This is why models struggle so much with East Coast storm tracks beyond 24-48 hrs. As as been said here by many, it results in the back and forth between runs and models. Small changes make a big difference.

Imagine if we get the Euro track further west with GEM lower pressure and higher winds.

Anything is possible with these record SSTs in the Western Atlantic. We saw our first 950mb low of the modern era just 4 years ago near the benchmark. Each of the models have been taking turns showing such low pressures. https://www.weather.gov/okx/Blizzard_Jan42018 The development of the blizzard began along the southeast coast on Wednesday, January 3rd. An ampflying upper level trough spawned low pressure off the coast of Florida. The low underwent rapid intenisifcation from Wednesday night through the Thursday morning as it moved north-northeast along the coast. The low passed just east of the 40°N 70°W benchmark Thursday afternoon. The central pressure when the storm developed was around 1004 millibars at 1 pm Wednesday. 24 hours later, the central pressure fell to 950 mb which is a 54 millibar drop. The rapid intensification of the storm led to the heavy snow and blizzard conditions across portions of the region.

The record SSTs result in deeper low pressure, heavier precipitation, and stronger winds when storms can track close enough to our area.

A dusting here in SW Suffolk as the steady light snow is picking up in this band across LI.

You can bet if one of these long range SSW forecasts actually verifies, then it will be just in time for March.

The lack of solid Atlantic blocking has been a big issue so far for us this winter. While we were able to score the 6-10 snow with the early January PNA rise and tail end of the brief late December -AO, the Pacific flow has been too overpowering since then. The fast northern stream combined with +AO and been suppressing the southern stream. A solid Greenland block would have forced the stronger northern stream to buckle underneath getting us closer to the most active storm track. It’s always more of a challenge to rely exclusively on a North Pacific block without help from the Greenland -AO block. Hopefully, we can put together a nice snow event near the end of January and start of February just on the lingering +PNA and -EPO.

Simon Lee has a great tweet illustrating the differences so far between this year and last.

NYC came into February 2006 with 11.7” but had a SSW event which produced the KU. We had Dec and Feb -AO patterns that year with record warmth in January. 2013 was another SSW winter which had the KU in February. Last February was great due to the SSW and record -AO. Since we won’t have a SSW and a great -AO going forward, we need a nice snow event next weekend before we lose the +PNA block.

The next 10 days or so will probably determine whether we make it to normal snowfall on the season. Winter is a bit like a football game. We can’t keep missing opportunities and hope to make it all up near the end of the game. We would need a nice snowstorm next week plus any snow we can pick up in February and March in order to reach near to above normal snowfall with the new higher 30 year averages.

30 day patterns have been the norm for us since the start of November. There have been regime shifts near the beginning of each new month . Our last change occurred in early January and was accompanied by the best snowstorm of the season. Let’s hope we can put together a nice snowstorm near the end of January as we move to the next winter pattern in February.

From all the historical accounts, the winter of 1779-1780 was the coldest winter on record during that era. https://www.nps.gov/morr/learn/education/classrooms/upload/HARD-WINTER-P.pdf ALL REPORTS INDICATE THAT THE WINTER OF 1779-80 IS THE WORST WINTER EVER KNOWN IN THE NORTHEAST UNITED STATES David M. Ludlum in his book Early American Winters 1604-1820, in the chapter on “The Hard Winter of 1779- 80” writes that it was“the most hard difficult winter....that ever was known by any person living. There has been only one winter in recorded American history during which the waters surrounding New York City have frozen over and remained closed to all navigation for weeks at a time...the Hard Winter of 1780.” According to Ludlum, January 1780 rated as the most persistently cold calendar month in the history of the eastern United States and “The severity of the 1780 season reached all parts of the colonies Reports from Maine southward along the seaboard to Georgia, and from Detroit down through the interior waterways to New Orleans, all chronicled tales of deep snow, and widespread suffering.” Ludlum believed that his research definitely showed that the season of 1779-80 in the eastern United States well deserved the name given to it by the people that experienced its effects....The Hard Winter EYEWITNESS ACCOUNTS SUPPORT THIS BELIEF William Smith (a loyali<t living in New York City) record< in his diary that on January 16, 1780, people were walking across the frozen Hudson River from New York to Paulus Hook (today Jersey City) New Jersey. A Hessian <oldier, Johann Dohla recorded in hi< diary on January 30, “The North (Hudson) and East rivers were frozen solid. The ice was checked and found to be eighteen feet thick. All ships were frozen in, and it was possible to cross over the North (Hudson) River on foot, riding or driving, without fear.” Later, (on February 22) Dohla wrote “Today the North River ice began to break, after having been frozen for nearly seven weeks.” A German officer, Major Baurmei<ter wrote, “The severe winter covered the North River with ice early in January; even where the current of the rivers <wifte<t, the ice was eleven feet thick, in spite of the fact that it is 1,800 yard< wide between Fort George (today Battery Park, New York City) and Powles Hook.” February 1780 seems to have been even colder: On February 10, William Smith mentionsin his diary that a few days earlier a “24 Pounder” (that i<, a cannon that fired a solid ball weighing 24 pounds—the entire cannon weighed three tons) was rolled across the Hudson River to PaulusHook (today part of Jersey City, New Jersey.) Smith goes on to say that even a heavy load as this it made no impression on the ice. On the night of February 10th, Smith heard that four to five hundred British cavalry rode their horses across the river IIIIIIIIIII MANY ACCOUNTS MENTION UNPRECEDENTED CONDITIONS A teacher in Yale College (New Haven, Connecticut) recorded approximately twenty days with snowfall, and a total of 95 inches of snow that winter. People walked across the Sound from Stanford, Connecticut to Long Island . Others walked from Rhode Island mainland to Block Island. Chesapeake Bay and the York River in Virginia froze over for the first time since Europeans settled there. Many people mentioned in letters that they could not remember a winter as bad.

The temperatures this month are certainly feeling more winter-like for a change. NYC already has 5 days with a low under 20 this January with more to come. This is the most for any winter month in 3 years. These colder winter months have been few and far between since 15-16. Colder than average months bolded with 5 out of 20 Monthly Number of Days Min Temperature < 20 for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Season 2021-2022 0 5 M 4 2020-2021 0 2 1 3 2019-2020 1 0 2 3 2018-2019 0 5 2 7 2017-2018 5 13 2 20 2016-2017 2 2 2 6 2015-2016 0 4 5 9

Yeah, March 2001 was pretty bad. But the writing was on the wall for January 2008. Each run from 3 days out was cutting back on the snowfall. The morning of the storm several models had much less snowfall than they were showing from the days before.

Since I have a frame of reference back to the 70s, I consider a model bust a complete miss of the P-Type or storm track from the day before for a high impact event. January 2000 fits that description with the storm coming hundreds of miles west from the day before. There was no storm forecast for many sections that got warning level to historic snows. I would consider January 2015 a large model error with a 60 mile + shift in the track to the east from the day before. We still got warning level snows around NYC and Western LI, but the jackpot shifted out to our east. Had the storm shifted hundreds of miles east and dropped no snow in NYC, then I would call that a bust. This happened several times in the 70s and 80s. We haven’t seen a complete P-type bust from the day before for a major event in a while. The most memorable one for me was 1-20-78. The forecast from the day before was for rain heavy at times. The next morning we had 12-18” on the ground. But I guess the term bust can be highly subjective.

It will be interesting to see if we can end the pattern with a nice snowstorm like we had at the beginning of it on January 7th. Sometimes we get bookend snows at the beginning and end of new patterns. Since the start of November, it has been a steady 30 day pattern followed by a shift at the beginning of each new month.

The RGEM has really been improving in recent years with continued upgrades. Unfortunately, there have been no NAM upgrades since 2017 when they decided to move toward developing a FV3 based CAM. But we have seen several problems with the the FV3 GFS changes. So we are stuck with an older version of the NAM until a replacement is ready. If the FV3 issues with the GFS are any indication, it may take a while for a suitable NAM replacement. Meanwhile, models like the RGEM will continue to pull ahead. The HRRR is often hit or miss in these situations with too much of a cold bias. https://vlab.noaa.gov/web/environmental-modeling-center/fv3-convective-allowing-forecast-system NAM development was frozen after the March 2017 upgrade, and RAP/HRRR development with the WRF-ARW model will cease after the RAPv5/HRRRv4 upgrade in 2020. However, operational execution of these modeling and associated DA systems will continue until comparable FV3-based systems are able to give similar performance.

34° and light snow here in SW Suffolk.

The models have become much more accurate than they were in the past. But in those days, we didn’t have weather forums and twitter posting every long range model snowstorm forecast. Models never have done particularly well with East Coast storm tracks past 3-5 days. Every once in a while a model like the Euro would score a long range win. This happened in January 1996 and February 2013. But we often forget how many long range misses the models had between the few long range successes. In the 70s and 80s, we often didn’t even know the storm track or P types a day before the storm. The forecast a day before the Jan 78 snowstorm with 12-18” was for rain heavy at times. That was my first school snow day in the 1970s that I can remember. Numerous snowstorm forecasts like in 1980 from a day before went OTS during nowcast time. The January 1987 forecast was for snow changing to rain hours before the storm started. Instead we got a heavy wet 10” of snow in about 5-6 hours. Our last actual model bust from a day before was January 2000. We went from no snow to record snows in the Mid-Atlantic. Nothing like that has happened in over 20 years. So that represents a great improvement. Perhaps the eventual Euro and EPS upgrade to convection permitting 3-5 km resolution will extend the forecast range for East Coast snowstorms. But we may not know until they actually try it.

We got the colder Pacific Ridge pattern this month. But record Pacific Jet from December never fully relaxed. So it served to suppress the STJ too far to our south. Hopefully, we can get a larger snow event before the retrogression of the ridge back to the Aleutians and milder Western Trough returns in early February.