Winter 2022-2023 Conjecture

[40/70 Benchmark]

We are about "due" from an anecdotal sequencing perspective...

[ORH_wxman]

14 minutes ago, 40/70 Benchmark said:

We are about "due" from an anecdotal sequencing perspective...

Yeah it's about every 20 years or so it happens.

[PhineasC]

Hopefully a more normal winter here. Already saw back to back duds. 

[40/70 Benchmark]

15 hours ago, raindancewx said:

The last two winters were both pretty cold in Nino 4 (DJF). Here are some relatively similar three year periods.

Before I was on any of these forums I vaguely remember using 1957-58 and 1985-86 in a blend as an estimate for 2014-15, for the rapid warming of Nino 4 in 2014-15 after two colder Nino 4 years in 2013-14 and 2012-13.

DJF 2020-21, 2021-22, 2022-23:  27.32C / 27.85C

DJF 1983-84, 1984-85, 1985-86:  27.56C / 27.59C / 28.11C

DJF 1955-56, 1956-57, 1957-58: 27.05C / 27.77C / 29.02C

DJF  2007-08, 2008-09, 2009-10: 26.97C / 27.48C / 29.41C

1985-86 (x2), 1957-58 (x2), 2009-10 is a pretty interesting blend to say the least.

Nino 4 in the blend: 27.24C / 27.64C / 28.73C as the estimate for 2022-23.

Personally expecting hermaphrodite ENSO conditions in the July-June year. I don't mean Neutral - I think we'll switch phases in the year, rather than simply moving half a step from Neutral in Summer to El Nino or La Nina in winter.

Interesting take....I wouldn't be angry if this worked out.

[Go Kart Mozart]

On 3/16/2022 at 2:37 PM, Great Snow 1717 said:

I equate using analog years during this time of climate change to someone thinking a starting pitcher who threw 85-90 mph back in the 90's would have  the same success now that he had back then. Jamie Moyer for example. Moyer would get crushed if he was pitching now. 

I dunno.  Nestor Cortes for the Yankees has been lights out throwing dead fish at batters.  I think there is still a place for someone who can pitch.

[Great Snow 1717]

22 minutes ago, Go Kart Mozart said:

I dunno.  Nestor Cortes for the Yankees has been lights out throwing dead fish at batters.  I think there is still a place for someone who can pitch.

 

22 minutes ago, Go Kart Mozart said:

I dunno.  Nestor Cortes for the Yankees has been lights out throwing dead fish at batters.  I think there is still a place for someone who can pitch.

Let's talk when Cortes has made 75 career starts......

[40/70 Benchmark]

On 4/25/2022 at 8:59 AM, Great Snow 1717 said:

 

Let's talk when Cortes has made 75 career starts......

Bieber only throws low 90s...so didn't vintage Greinke in his prime. I opt for high velo, too, but you can succeed with great command, there just isn't the same margin for error.

[Great Snow 1717]

1 hour ago, 40/70 Benchmark said:

Bieber only throws low 90s...so didn't vintage Greinke in his prime. I opt for high velo, too, but you can succeed with great command, there just isn't the same margin for error.

But both are still above the 85-90 that I mentioned...

[40/70 Benchmark]

17 hours ago, Great Snow 1717 said:

But both are still above the 85-90 that I mentioned...

Yea, under 90mph would be tough....aside from maybe a good knuckleballer...

[CoastalWx]

Could see a below normal winter north of pike and east of 93. 

[CoastalWx]

Nina digging in strong for now. I haven’t seen the latest projections for winter, but will probably aid in active tropical  season. 

[40/70 Benchmark]

1 hour ago, CoastalWx said:

Nina digging in strong for now. I haven’t seen the latest projections for winter, but will probably aid in active tropical  season. 

Lots of warmth developing in the subsurface out west, but cold holding strong near S America....don't mind seeing that.

[CoastalWx]

39 minutes ago, 40/70 Benchmark said:

Lots of warmth developing in the subsurface out west, but cold holding strong near S America....don't mind seeing that.

We do like a cold east. Eastern Pacific and eastern US.  

[40/70 Benchmark]

42 minutes ago, CoastalWx said:

We do like a cold east. Eastern Pacific and eastern US.  

Obviously its obscenely early to glean too much from that, but sometimes you can start to see some trends even this early.

[ORH_wxman]

1 hour ago, 40/70 Benchmark said:

Lots of warmth developing in the subsurface out west, but cold holding strong near S America....don't mind seeing that.

 

59 minutes ago, CoastalWx said:

We do like a cold east. Eastern Pacific and eastern US.  

 

16 minutes ago, 40/70 Benchmark said:

Obviously its obscenely early to glean too much from that, but sometimes you can start to see some trends even this early.

Trends are def good. When you get defined east-based Nina, December comes in big fairly frequently (see 2017, 2007, 2005, 1995, 1970)...keeping it weak is better though for later in winter as noted by the '95 and '17 analogs....'05 didn't really follow that mold though you could say Feb '06 was a bit unlucky and we should've scored more than that one coastal.

[40/70 Benchmark]

9 minutes ago, ORH_wxman said:

 

 

Trends are def good. When you get defined east-based Nina, December comes in big fairly frequently (see 2017, 2007, 2005, 1995, 1970)...keeping it weak is better though for later in winter as noted by the '95 and '17 analogs....'05 didn't really follow that mold though you could say Feb '06 was a bit unlucky and we should've scored more than that one coastal.

March 2006 was very unlucky....cold and dry. 

Research actually shows that December is usually the milder part of east based seasons, as in this past winter...December is usually the coldest month in central based events.

[40/70 Benchmark]

There exist some notable differences between these two disparate types of la nina events. Here are a couple of schematics outlining these differences:

Differences between east-based La Nina's & central-based La Nina's 

Figure A is east-based. Figure B is central-based

DJF 500mb for East-based years:

 

 

DJF Temps

 

Ironically in east-based years JFM is colder than Dec. Dec is typically the warmest month in the

 east-based years, which runs counter to typical cold ENSO climo.

JFM 500mb east-based years

 

 

 

JFM Temps
 

 

 

 

 

 

Compare all of that to central-based La Nina years:

DJF 500mb
 

 

 

 

DJF Temps
 

 

 

December is the coldest month for central-based Nina's. 

One thing worth noting is not all East-based Nina's are frigid, as there is variability due to the relatively weak

 ocean-atmosphere coupling. This is because many east-based events, as is the case with modoki el nino events, are 

weaker. You can have warmth, especially if the event is weaker, and one such case is 2005-2006.

Likewise, there were some weak modoki events that were fairly cold across the eastern US, such as 2000-20001.

[raindancewx]

My research going into the 2020-21 winter showed that intense early heat waves in the SW US typically precede severe cold waves/months/or even winters down here during La Ninas. I defined intense early heat as hitting 90 or hotter in early May, when average highs locally are still in the mid-70s. We've got several chances at hitting 90 again this week, and a La Nina could easily hold through winter - might even hit 90 again for the first time on the same day as 2020 on 5/7.

It's much more typical to hit 90 for the first time in late May. This is for the past 30 La Ninas over the past 90 years or so. I had lows bottom out at 40 ish with rain in September 2020 within 36 hours of hitting 96 degrees, and then snow, with lows at 19 degrees after hitting 76 within 48 hours in October when the MJO phase repeated. Close to 9 inches of snow that October at my place. Severe cold and a lot of snow in February too obviously. March was active too.

The 2021-22 winter was 36, 51.4F, very near the trend line, and 2020-21 was 7, 49.6F, also very near the trend line. Actually, the two most recent winters increased the correlation quite a bit. P value is low enough for me to believe it's a pretty robust relationship locally. I guess my point is, the billion forecasts calling for a hot SW winter with a La Nina will probably be wrong given the heat coming so early this year.

 

[40/70 Benchmark]

On 5/4/2022 at 9:43 PM, raindancewx said:

My research going into the 2020-21 winter showed that intense early heat waves in the SW US typically precede severe cold waves/months/or even winters down here during La Ninas. I defined intense early heat as hitting 90 or hotter in early May, when average highs locally are still in the mid-70s. We've got several chances at hitting 90 again this week, and a La Nina could easily hold through winter - might even hit 90 again for the first time on the same day as 2020 on 5/7.

It's much more typical to hit 90 for the first time in late May. This is for the past 30 La Ninas over the past 90 years or so. I had lows bottom out at 40 ish with rain in September 2020 within 36 hours of hitting 96 degrees, and then snow, with lows at 19 degrees after hitting 76 within 48 hours in October when the MJO phase repeated. Close to 9 inches of snow that October at my place. Severe cold and a lot of snow in February too obviously. March was active too.

The 2021-22 winter was 36, 51.4F, very near the trend line, and 2020-21 was 7, 49.6F, also very near the trend line. Actually, the two most recent winters increased the correlation quite a bit. P value is low enough for me to believe it's a pretty robust relationship locally. I guess my point is, the billion forecasts calling for a hot SW winter with a La Nina will probably be wrong given the heat coming so early this year.

 

Any thoughts on why the big March didn't materialize? I feel as though the rapid onset of solar cycle 25 nixed the chances for any SSW and/or substantial/sustained blocking. 

We out here in the east are really lucky this la nina ended up so east based because everything else went wrong...it would have been very ugly. The aleutian ridge being displaced so far NW, per east-based a nina climo, salvaged somewhat of a winter.

[40/70 Benchmark]

1 minute ago, 40/70 Benchmark said:

https://easternmassweather.blogspot.com/2022/05/winter-2020-2021-seasonal-recap.html

Winter 2020-2021 Seasonal Recap & Forecast Verification; Mixed Results Abound

Pacific Timing Issues Plague the First Half and Misdiagnosed Arctic Nullifies Forecast Big Ending

Pacific Overruled the Arctic in December

 

While the overall tone of the 2021-2022 Eastern Mass Weather Outlook included a cold phase oriented Pacific, as evidenced by the primary extra tropical Pacific analogs of 2010-2011, 1970-1971, 1974-1975, 1955-1956, 1954-1955, 1964-1965, 2020-2021, 1988-1989, 2011-2012, 1998-1999, 1999-2000, 2007-2008, 2008-2009, 1975-1976, it was perceived that there was support amongst the analogs for a more variable PNA pattern during the early portion of the winter season. Thus the December portion of the forecast called for some variability within the PNA domain, which in conjunction with the forecast high latitude blocking would have ultimately led to an active month of winter weather culminating the week of Christmas. This proved to be a mistake. While a significant interlude of high latitude blocking did in fact verify, the Pacific volatility did not. In fact, December 2021 featured the most pronounced RNA pattern (-2.56) on record dating back to 1950. This was most similar to December 1955 (-2.07), December 1964 (-1.73), December 2008 (-1.41) and December 2010 (-1.78) from the extra pacific Pacific analog set. In hindsight, given the fact that the aforementioned composite contained the top 3 RNA months of December (1955, 1964, 2010) dating back to 1950, which included the top ENSO analog of 2010-2011, it was a glaring error to not forecast a very prevalent and static RNA in the mean for the month of December. 

There will be further exploration into the parallels to 1955-1956 later in this writing as it pertains to ENSO.

Here is the original narrative and forecast composite for the period:

December Analogs: 2007, 2000 (x2), 1974, 1970, 1995, 2005 (x2), 2017 (x2), 2008, 1983, 2020

"The polar vortex should take some assaults throughout the latter portion of November and much of December, however, it should remain intact and ultimately intensify and consolidate beyond the new year. This is consistent with basin-wide, mixed-type la nina events. While there may be a mild spell early in the month, it should ultimately turn active with a multitude of moderate snowfalls for the northeast, with the most significant event likely to occur the week of Christmas between the 19th and 26th. A white Christmas is highly likely for the majority of the region and a storm on the holiday itself is a distinct plausibility. Plan accordingly. Although the focus will be on the northeast via a mix of Miller B systems and southwest flow events whenever blocking relaxes, the mid atlantic should receive some snowfall due to a subtle subtropical influx coupled with a variable PNA.

The month should not be exceedingly frigid, as the very mild fall has ensured a late developing cold reservoir. Anywhere from near normal close to the coast to as much -2 departures well inland should cover the monthly departures".

Although the most prolific winter storm of the month throughout the northeast did in fact occur near the onset of the identified December 19 through December 26 period, it primarily impacted the northern half of the region, and was mainly rainfall throughout southern New England. More importantly, this particular event was the only noteworthy winter storm of note for the month in large part due to the development of the poorly forecast record RNA pattern. While the forecast episode of high latitude blocking in the NAO domain did in fact materialize as forecast by the holiday period, its development was concurrent with the formation of the strong ridge of high pressure to the south in response to the historically low heights along the west coast in conjunction with the extreme RNA pattern.

 

 This acted to create a very compressed flow between the southern ridge, and high latitude ridge in the vicinity of Greenland, which sheared off storm activity approaching from the active Pacific pattern.

 

Note in the annotation above that the two respective ridges of high pressure were situated at just the right distance from once another, at the appropriate latitude to attenuate the storm systems on approach to the Great Lakes. Although this evolution is similar to the year 1970 from the list of analog composite, which featured near record snows for the  month of December, in this instance the heights out west were just so low that heights to the east were elevated enough to be create said compression. Storm systems ejecting out of the PNW were sheared by the compressed flow as they neared the great lakes, so that what we were left with at the longitude of New England was a multitude of minor disturbances, instead of any larger, more discrete, congealed or phased system. This pattern acted to negate what was envisioned last fall as being a very active period with a multiple moderate snowfall events from the period leading up to the holidays and beyond. In turn, the higher heights downstream from the deep trough in the west shifted the core of the warm anomalies from the forecast position in the southwest, into the Texarkana region. It also caused temperatures in the east to be slightly warmer than anticipated.

 

Forecast:

 

Actual:

 

 

 

In summary, the most important aspect of monthly forecasting is correctly identifying periods of volatility from the seasonal base state. While this does not show up in the overall DM seasonal composite, it is key to correctly diagnosing the sequential evolution of a season. And while the Pacific pattern throughout the month of December was essentially a more amplified version of the overall DM forecast base state of the Pacific, it certainly was not the forecast period of variability and perhaps slight variation that was forecast. This essentially rendered the well forecast high latitude blocking a moot point, and the forecast sensible appeal did not materialize due to the severe and static RNA throughout the month that was flagged by the extratropical Pacific Composite.

 

January 2022 Colder & Snowier Than Forecast 

 

The most notable issue with respect to the first half of the seasonal forecast was that the fact that the timing of the forecast evolution was rushed by approximately two weeks due to the misdiagnosis of the PNA period as occurring during the month of December,  rather than January. Thus while the first half of winter was fairly well forecast in the aggregate, the monthlies left something to be desired in that December was milder with much less snowfall than forecast and January more wintery than anticipated.

Timing is everything, indeed. And given that the primary ENSO analog was in fact in 2010-2011, the severe December RNA and PNA driven severe winter stretch in January should have been more accurately forecast with respect to the monthly progression.

 

Given the fact that the PNA pattern did evolve during the month of January as it did in the analog year of 2011, the forecast harsh period ultimately evolved into more of a "delayed but not denied" element of the winter outlook. As evidenced by the excerpt pertaining to the January portion of the outlook released on November 6, 2021, the month was expected to begin cod and snowy, before transitioning to a mild, Pacific jet dominated look around mid month.

 

January 2022 Outlook

 

January Analogs: 1955, 1956, 1971, 1996, 2006 (x3), 2001, 2018, 2012, 1989, 1965, 1976

 

There is a slight chance of a KU magnitude, Archambault type east coast snowfall between approximately December 28th and January 11th, as any residual high latitude blocking erodes and heights lower in the vicinity of Alaska and western Canada. Heights will also lower in the western US as the aleutian ridge retrogrades into the pacific and a sustained RNA accompanies the development of an active, zonal pacific storm track. The core of the warmth should center in the northern plains as the pacific jet eradicates the supply of cold from much of the continent, however, the degree of warmth in the northeast should not be prohibitive of some wintery weather during this peak climo period. Although mixed precipitation and southwest flow events should be the rule, and major pure snow events will be difficult to achieve outside of the higher terrain of upstate New York and central/northern New England. The forecast is for monthly departures to range anywhere from +1 to +3 degrees, but the ceiling is quite high and the potential is there for several degree positive departures. This has the potential to bean exceptionally mild month akin to February 2018.

 

Note that the powerful bomb cyclone that became known as the Blizzard of '22, similar to the one that occurred during the analog season of 2017-2018 on 1/4/2018, took place roughly two weeks beyond the 12/16 to 1/11 favored window of time, during which the January 11, 2011 blizzard also took place. Additionally, Boston, MA recorded its 8th snowiest month and 4th snowiest month of January on record with 36.2",  just 2.1" behind the month of January 2011, which occurred during the primary ENSO analog season. Thus while the first half of winter 2021-2022 largely paralleled the overall tenor of the primary analog seasons, the timing in relation to the forecast sequence of events left much to be desired due to the failure to forecast the PNA period correctly. This discrepancy between the forecast timing of the pattern evolution and what actually transpired dictated that the second half of January did not turn mild, and instead featured the climax of the harsh period with several bouts of arctic air masses, including sub zero temperatures, as well as the blizzard. The month of January clearly finished colder than forecast, just as the month December was milder than forecast because the Pacific patterns were reversed.

 

 

The month finished approximately 1-2 degrees below average across the region, which was about two degrees colder than the forecast range. In summary, while the DJ first half of the boreal winter season was fairly accurately forecast accurately forecast in the aggregate, the monthly evolution with respect to the timing sequence was relatively poor due to the +PNA interlude occurring during the month of January, instead of December, as forecast. 

The month of February, on the other hand, was by far the best forecast from a sensible weather stand point.

February 2022 Well Forecast at the Surface; Poorly Forecast Stratosphere

 

Here is a review of the February 2022 portion of the winter outlook that was originally issued early last November.

Forecast Review:

 

 

February 2022 Outlook

February Analogs: 1955, 1956, 1971, 1996, 2006 (x2), 2001 (x3), 2018, 2012, 1965, 1975, 1972, 2008, 2011,1985

 

"The month of February is the most difficult portion of the forecast because there will be a great deal of flux. Not only between the potential SSW that may parallel that which was observed on February 13, 2018:

But also a PNA that is more likely to fluctuate from the more stagnant RNA of January, as la nina begins to decay and loosen its grip on the pacific. Here is an extended range forecast for the polar vortex from the European model courtesy of meteorologist Giacomo Masato:

Note that guidance implies a recovery to a strong vortex in January, as per the Eastern Mass Weather forecast, however, the analogs suggest that the disruption could even begin to take place in later January. This is crucial to the forecast because if it does in fact delay until March, then blocking will not redevelop until spring and the second half of the season could be mild.

Nonetheless, the month of February should begin very mild, but winter is likely to gradually return as the Pacific also becomes a bit less hostile and the Aleutian ridge that had retrograded last month begins to edge back closer to the west coast and a bit more poleward towards Alaska. This will allow more proficient cold delivery through the plains to bleed into the northeast, leading to an active pattern of overrunning, SWFEs and Miller B cyclogenesis.

The month should average anywhere from near normal to 2 degrees above average. Warmest near the east coast and the mid atlantic, coldest north and well inland. But again, the risk is for a much warmer outcome.

The primary risk during February is that if a major disruption of the PV does NOT occur, then the month may remain fairly mild".

 

 

The Results:

 

In hindsight, this was a very accurate forecast overall in terms of sensible weather, as the region did indeed finish slightly above average for the month, and the primary modes of cyclogenesis were in fact overrunning, SWFEs and Miller B events. 

 

Forecast Precipitation:

 

Versus Actual:

 

 

 

Actual Temps: 

 

 

Versus Forecast Temp Departures
 

 

Forecast H5 anomalies:

The poleward ridging in the Pacific that is so reminiscent of the eastern biased la nina composite was very well forecast. 

 

This did indeed allow for the delivery of arctic air throughout the east at times, however, note the absence of high latitude blocking

 

 Versus the forecast analog composite:

 

The primary reason for this discrepancy with respect to the polar domain is the failure of the major SSW predicted to occur between approximately January 23 and February 11. 

 

While there is no way to know for certain why the negative  Quasi Biennial Oscillation (QBO)  and eastern biased cool ENSO couplet failed to result in a SSW as forecast, one potential reason is the sharper than anticipated increase in solar activity via a  solar flare in the fall of 2021. This acted to effectively end the solar minimum and initiate solar cycle 25.  

 

 

 

 

Many papers (such as this one: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JD006283) have attempted to establish a link between the solar cycle and stratospheric blocking patterns during the northern hemisphere winter season. In general, years near and shortly following a solar minimum tend to have a weaker stratospheric polar vortex and are more prone to blocking, with the opposite true in solar maxima winters. Although an increase in activity was noted last fall, the forecast rationale was that it was unlikely have a major impact due to a potential atmospheric lag in conjunction with the depth of the previous solar minimum. However, this was cited as a potential forecast risk with respect to the second half of the winter that would appear to have come to fruition with greater than 55 sunspots likely to be observed between June 2021 and July 2022.
 

Ultimately this did not impact the February monthly temperature departure as theorized in the winter outlook last fall because the more hostile polar fields were offset by a slightly more favorable Pacific than advertised, thus the forecast was still successful. And the warmer risks mentioned as a result of SSW failure did not materialize. However, the failure of the SSW was of a great detriment to the March portion of the forecast.

 

Overall Poor March Verification Due to Misdiagnosis of Polar Stratosphere

 

The March portion of the winter outlook released this past fall was predicated upon a major disruption of the the polar vortex via a February Sudden Stratospheric Warming (SSW) event, which obvious did not happen. While the forecast was for monthly temperature departures across the region anywhere from 1 to as much as 3 degrees below average with above average snowfall, it was explicitly stipulated that if the aforementioned SSW did not occur, than the risk was significantly warmer with less snowfall.

This is precisely what transpired.

 

Note thE pronounced and distinct lack of blocking for the vast majority of the month, as evidenced the the NAO/AO charts depicting largely positive values of each below.

 

 

There was a slight disruption of the polar vortex during the latter third of the month, which led to a fleeting period of warming throughout the polar stratosphere. 

 

It is this period that corresponded with the window of slightly greater polar heights and colder air across the forecast area due to a bifurcation of the vortex in the lower levels of the stratosphere, near the tropopause.

 

 

However, this did not represent a major SSW, nor did it result in any significant snowfall to speak of across the area. despite the colder temperatures.

This is again theorized to be at least in part due to the robust onset to solar cycle 25.

 

March 2022

 

Here is how the month actually evolved:

Actual temperature anomalies were anywhere from 1-3 degrees above average, as compared to the forecast, which called for monthly departures of  1-3 degrees below average. 

 

The result was not only warmer weather than forecast for the month of March, but also less precipitation, as the primary storm track remained inland due to the prevalent southeast ridge as a result of the dearth of high latitude blocking.

Thus a predominate storm track through the Great Lakes, as opposed to the coastal NE or offshore meant both less precipitation and a larger percentage of said precipitation falling as rain. This equates to below average snowfall and was obviously in contrast to the March forecast from this past November.

 

March Analogs: 1956 (x2), 1984, 1996, 2006 (x2), 2001 (x3), 2018 (x2), 1975, 2011

 

The first half of March should be blocky with an improving Pacific. The month should feature both Miller A & B cyclogenesis, as there are signs that the subtropical jet may enter the scene in addition to the active northern stream. This could be a very volatile set up with immense storm potential should the two streams phase. There is a relatively strong chance of a KU magnitude event between March 1st and 15th. The failure risk is that the SSW does not materialize, which could alter the forecast dramatically.

Monthly departures anywhere from 1-3 degrees below average with the coldest across the interior and above average snowfall from the mid atlantic into New England. This should be a very active east coast pattern rivaling that of March 2018 and 2001, though with perhaps more southern stream involvement.

The pattern may rapidly break down later in the month with an early spring to reward beleaguered residents of the northeast if the vortex does indeed weaken a bit earlier than the Euro guidance suggests, as forecast by Eastern Mass Weather.

This March forecast, again, is contingent upon the development of high latitude blocking, and the risk is for a warmer outcome should that not occur. or be delayed, as the European guidance hints at.

 

 

 

 

 

While ultimately long term seasonal guidance such as the European was correct in forecasting a dearth of high latitude blocking during the 2021-2022 winter season, conceivably due to the faster than anticipated onset of solar cycle 25, this cited forecast risk was primarily only a factor with respect to sensible weather during the month of March. This is likely why winter ended much milder and benign than anticipated last fall.

 

December-March 2021-2022  Composite Verification & Summarization

Here is the H5 forecast composite for the December through March 2021:

 

 

 

 

Versus reality:

 

 

Its clear why December was so much milder than expected, as the immense RNA materialized then, instead of January, as forecast. And the major NAO block that developed was rather ephemeral and frankly overwhelmed by the magnitude of the record RNA block to the west.

There were two primary weaknesses of the outlook issued from last fall, which served to negate one another to a degree and drove the pattern for the final 3/4 of the forecast period post New Year.

1) As previously discussed, the sun became more active faster than originally anticipated, which ultimately served to augment the polar vortex more than forecast. This is why the latter portion of the season, namely March, ended up so much milder than anticipated.  But the question of why January and February did not remains.

2) Note that in the juxtaposition of the DM forecast composite and the verification composite above, the Aleutian ridge was more pronounced in reality than forecast. Additionally, the polar vortex is also stretched and elongated onto our side of the globe, which also aided in the delivery of cold air.

This is what produced some rather harsh periods of winter weather throughout the eastern US in especially January, but even into March, despite a fairly robust polar vortex.

 

However, as the season aged and the month of March ensued, the cross polar flow abated and the active end of winter that was forecast across the east failed to materialize in the absence of high latitude blocking that was presumably attributed to a sharp increase in solar activity. 

 

 

Thus winter truncated in the east, despite the easterly QBO working in concert with what ultimately verified as a very significant and solidly eastern biased la nina. In fact, this was the most intense and eastern centered la nina since 1955-1956.

 

Poleward Aleutian Ridging a Function of East-Based La Nina

La Nina was forecast by Eastern Mass Weather to peak near the threshold of weak-moderate within an anomaly range of -.9C to -1.1C during the NDJ tri-monthly period. This portion of the forecast was exactly correct, as it achieved a peak ONI value of -1.0 during the NDJ period. 

However, it was measured at approximately -.8 by JAMSTEC on the el nino modoki index (EMI), which with the term "modoki" referring to west based, means that this particular event was very solidly east-based.

 

The forecast was for it to register between -.2 and -.4 on the EMI scale, or slighly east of neutral, making it a hybrid event similar to this past 2020-2021 and the 2010-2011 seasons, respectively. 

 

Here are these two seasons as compared how this past event materialized:

 

2010-2011:

 

 

2020-2021:

 

2021-2022:

 

Note that how in contrast to the two aforementioned hybrid seasons, just about all of the significant cool anomalies are relegated to east of 150 degrees longitude and hug the coast of Peru.

This is much more reminiscent of how our east-based composite looks.

 

Here is the synoptic forcing scheme associated with the above east-based la nina composite:

 

 

Considering the close similarity to the east-based la nina composite at the surface in terms of placement of max SST anomalies, it would be a reasonable inference to assume that the forcing from this past la nina was redolent of the above east-based composite:

 

Indeed was the case. Note that the warmer anomalies near the dateline ensure that forcing remains over the central and western Pacific, similar to the weaker la nina composite. Sinking air that discourages convective forcing is focused well east of the dateline. Also evident is that the Aleutian ridge focuses more to the northwest relative to the modoki, cp event. This often entails a protrusion of said ridge into the polar region at times, which likely contributes to the lower heights over the mid latitudes:

 

 

This explains the significant expansion of the Aleutian ridge into the polar domain this past season, which countermanded the stronger than forecast polar vortex to a degree, thus salvaging some semblance of a boreal winter across the eastern US.

 

 

Note that of the eastern-based la nina data set, the most intense cool-ENSO event of the composite, 1955-1956, was comparable to this past event in terms of both intensity and structure, thus it is prudent to conclude that this season should have been at least the primary ENSO analog and quite possibly a primary general analog. This harkens back to the major oversight alluded to at the onset of this writing. That being not having weighed heavily enough into the forecast the fact that the December forecast composite contained the most severely RNA Decembers on record, which included the aforementioned 1955-1956. This season was not only the superior ENSO analog in hindsight, but also featured the most prominent December RNA on record until this past December. Additionally, it also would have allowed more insight to be gleaned into the fact that this past la nina would very biased fairly heavily to the east.

 

Here is how the national forecast temperature composite verified:

 

 

Vs reality:

 

 

 

DM mean temperature anomalies were generally near normal to slightly above average across the northeast, as forecast.

 

Finally, the precipitation pattern verified as forecast, although the anomalies were slightly more extreme and the mean storm track slightly further inland than forecast due to the absence of polar blocking.

 

 In summary, Eastern Mass Weather correctly identified that winter 2021-2022 would have interludes of rather severe winter weather due to the spasmodic, poleward expansion of the Aleutian ridge that induces cross polar flow and is inherent of an east-based la nina. However, Eastern Mass Weather poorly forecast the state of the polar stratosphere and thus the strength of the polar vortex, presumably attributable to a failure to appreciate of how quickly and fervently solar cycle 25 began this past fall and into the boreal winter season. The end result was a fairly well forecast winter from a sensible weather appeal that ended sooner than anticipated across the eastern US.

Here is a closer examination of how the teleconnection and snowfall prognostications fared.

December-March Teleconnection Forecast

 

 

The verification of the mean teleconnection values for the DM were congruent with the overall synoptic verification laid out above. Clearly Eastern Mass Weather underestimated the mean DM negative value of the PDO by a great deal (biased .82 positive) this past season, however, the seasonal PNA value was forecast relatively accurately (actually biased -06 negative) despite the early season timing issue.

 

 

 

 This validates the position that the first half (DJ) of the winter season was forecast fairly well in the aggregate, despite mistakenly having forecast the extreme period of RNA in January, as opposed to December. This timing evolution was on par with the 2010-2011 and 1955-1956 analogs. 

 

Index Value	Predicted '21-'22 DM   Value Range	Actual  '21-'22 DM Value	Forecast Error
Pacific Decadal Oscillation (PDO)	-1.00 to -1.30	-2.12	Biased .82 Positive
Perennial North American Pattern (PNA)	-.25 to -.55	-.19	Biased .06 Negative
ENSO	NDJ -0.9 to -1.1 EMI: -.2 to -.4 (slightly east-hybrid)	NDJ -1.0 EMI: -.8  ( moderately east-based)	Timing & Intensity of ENSO Peak Verified. However, forecast was biased .4 West-based.
(J-M) East Pacific Oscillation (EPO)	+.45 to +.75	+.01	Biased +.44 Positive
Arctic Oscillation (AO)	-.45 to -.75	+.72	Biased Negative 1.17
North Atlantic Oscillation (NAO)	-.10 to -.40	+.96	Biased Negative 1.06

ENSO was forecast with absolute precision as it pertains to the peak ONI value of -1.0 during the NDJ tri-monthly period. But it was forecast to be a hybrid season with an eastern tilt, registering an EMI value of between -.2 and -.4 during its peak. The fact that la nina ended up being firmly east-based (-.8 EMI) led to the forecast poleward protruding Aleutian ridging being even more prominent than forecast, especially during the month of January, which is evidenced by the fact that the DM mean EPO value (+.01) verified as essentially neutral instead of the solidly positive forecast range of +.45 to +.75. This helped to counteract the fact that a more rapid start to solar cycle 25 prevented much in the way of blocking in the polar domain, as forecast. Thus despite the DM mean AO/NAO values registering as solidly positive (+1.17 & +1.06, respectively), in contrast to the forecast -.45 to -.75 & -.10 to -.40, respectively), the overall forecast synoptic appeal was fairly well forecast with the notable exception of the month of March.

 

 

 

 That being said, the snowfall forecast, which is inherently subject to a high degree of variance, anyway, was certainly flawed across parts of the region.

December-March Snowfall Outlook Review

 

 

City	Predicted Snowfall	Actual	Forecast Error
Boston, MA	45-55"	54"	Verified
NewYork, NY(Central Park)	25-35"	17.9"	Snowfall Overforecast by 28.4%
Philadelphia, PA	17-27"	12.9"	Snowfall Overforecast by 24.1%
Baltimore, MD	10-20"	14.4"	Verified
Washington, DC	7-17"	12.3"	Verified
Albany, NY	65-75"	36.4"	Snowfall Overforecast by 44%
Hartford, CT	45-55"	31.5"	Snowfall Overforecast by 30%
Providence, RI	30-40"	43.5"	Snowfall Underforecast by 8.75%
Worcester, MA	80-90"	53.6"	Snowfall Overforecast by 33%
Tolland, CT	55-65"	50.6"	Snowfall Overforecast by 8%
Methuen, MA	70-80"	42.5"	Snowfall Overforecast by 47%
Hyannis, MA	15-25"	10"	Snowfall Overforecast by 33%
Burlington, VT	85-95"	70.7"	Snowfall Overforecast by 14.3%
Portland, ME	80-90"	44.1"	Snowfall Overforecast by 44.9%
Concord, NH	75-85"	44.6"	Snowfall Overforecast by 40.5%

 

 

The mean snowfall forecasting error for the 2021-2022 winter season throughout the 15 select mid atlantic and northeast locations was 25.4%. This ranked 4th amongst the eight seasons forecast. The seasonal forecast ranges verified in the cities of Boston, MA, Baltimore, MD & Washington, DC.

Snowfall was generally over forecast between 24.1% (Philadelphia, PA) and 47% (Methuen, MA) across the majority of the forecast area due in large part to the failure of the late season high latitude blocking to materialize. However, there was a narrow corridor in the vicinity of I-95 and I-84 in the mid atlantic and southern New England, where snowfall was fairly accurately forecast and even under forecast by 8.75% in Providence, RI. This is due to the fact that the aforementioned area proficiently accumulated snowfall during the favorable period of poleward Aleutian ridging during January and February, where as points slightly further inland experienced some close misses and lighter snowfalls. This was most notable with respect to the late January blizzard in southern New England, in which more high  latitude blocking likely would have led to faster and more proficient phasing and a wider expanse of blizzard conditions. Southeast of the narrow region of well forecast seasonal snowfall, across the cape and islands, snowfall fell short of the  forecast by 30% in Hyannis, MA due to mixed precipitation. Snowfall outside of the narrow I-84 and I-95 corridor was never able to reach the forecast totals because later in the season the high latitude blocking never materialized a a result of the more active sun. Snowfall totals across far northwestern New England, in Burlington, VT, ended up a mere 14.3% (70.7") under the forecast range of 85-95" due to the fact that blocking is less of a factor for snowfall in this region due to its distant interior location. 

 

The mean forecasting error with respect to the eight seasonal snowfall outlooks are as follows:

2021-2022: 25.4%

2020-2021: 11.7%

2019-2020: 678.3%

2018-2019: 90.4%

2017-2018: 15.6%

2016-2017: 36%

2015-2016: 71.4% 

2014-2015: 13.7%

Eight season running mean error: 117.8%

29/117 (24.8%) of snowfall outlooks have been under forecast.

61/117 (52.1%) of snowfall outlooks have been over forecast.

26/117 (22.2%) of snowfall outlooks have verified within the forecast range.

Below is the verification for ENSO, as well as the various teleconnections over the past several years:

 

Index Value	Seasons Verified	Mean Forecast Error	Forecast Bias
Pacific Decadal Oscillation (PDO)	0/6 Seasons	.66	Biased Negative 3/6 Seasons
Perennial North American Pattern (PNA)	1/5 Seasons	.15	Biased Negative 4/6 Seasons
ENSO	7/8	.01 too cold	Biased cold 1/7 Seasons
(J-M) East Pacific Oscillation (EPO)	3/6 Seasons	.39	Biased Positive 2/3 Seasons
Arctic Oscillation (AO)	0/6 Seasons	1.20	Biased Negative 5/6 Seasons
North Atlantic Oscillation (NAO)	0/6 Seasons	.95	Biased Negative 5/6 Seasons

 

   

Final Grade for 2021-2022 Season: C-

 

Graded last winter's outlook a C-.

[LibertyBell]

On 4/25/2022 at 8:59 AM, Great Snow 1717 said:

 

Let's talk when Cortes has made 75 career starts......

This is called high IQ pitching, the flame throwers will get injured and Cortes will just keep on pitching.

The human arm was not designed to throw 95+ mph consistently for more than an inning or two.

 

[40/70 Benchmark]

6 minutes ago, 40/70 Benchmark said:

That is exactly what I am driving at....yea, PNA is stochastic and prone to shorter term wave breaking, however, we are seeing the incongruency even at a seasonal level. This is something I have noticed in doing seasonal outlooks....you can't just assume positive correlation in the Pacific. You need to dig in and unearth more esoteric relationships, such as the tendency for east-based la nina to exert a powerful RNA presence in December. I think this is why la nina events of that ilk tend to improve later in the season, more like an el nino, as opposed to canonical la nina events, which tend to be front loaded. It was right there in neon lights within my data last season, but I completely missed the forest through the trees, and forecast that RNA pulse in January, instead. Dumb, considering my primary ENSO analog was 2010-2011, which was a harbinger of that very behavior.

 

[40/70 Benchmark]

I am going to go on record right now.....you guys heard it here first, but the winter of 2023-2024 is going to crush it.

Jury still out on this season...it could go either way, but take '23-'24 to the bank.

[40/70 Benchmark]

The path of least resistance is to scoff while offering an assortment of weenie and confused emojies, but take a look at el nino seasons coming off of 3 year plus cool ENSO cycles...its pretty iron clad.

If this year ends up an el nino, then it could be this year.

[RUNNAWAYICEBERG]

18 hours ago, 40/70 Benchmark said:

I am going to go on record right now.....you guys heard it here first, but the winter of 2023-2024 is going to crush it.

Jury still out on this season...it could go either way, but take '23-'24 to the bank.

That’s how I feel about my fantasy baseball team.

[40/70 Benchmark]

5 minutes ago, RUNNAWAYICEBERG said:

That’s how I feel about my fantasy baseball team.

Its seems tongue and check, but its honestly not....I'm dead serious. There is going to be a nice el nino (probably modoki) either this season or next.

[RUNNAWAYICEBERG]

47 minutes ago, 40/70 Benchmark said:

Its seems tongue and check, but its honestly not....I'm dead serious. There is going to be a nice el nino (probably modoki) either this season or next.

Oh I know you are, and put a lot of work into this. We are definitely due for one, that’s the only input I have lol but I’m not sure being do means much nowadays…I’ve been saying I’m due for an 18”+ snow event for like 5yrs running now and it hasn’t happened lol. 

[40/70 Benchmark]

1 hour ago, RUNNAWAYICEBERG said:

Oh I know you are, and put a lot of work into this. We are definitely due for one, that’s the only input I have lol but I’m not sure being do means much nowadays…I’ve been saying I’m due for an 18”+ snow event for like 5yrs running now and it hasn’t happened lol. 

I've been saying I have been due for something approaching normal or above snowfall 5 years running now and it hasn't happened lol.

[CoastalWx]

We 04-05.

[40/70 Benchmark]

16 minutes ago, CoastalWx said:

We 04-05.

Maybe sensible weather wise....but off the top of my head, I would toss out 1957-1958, 1976-1977 (obviously modified), 1986-1987, 2002-2003, 2014-2015 (obviously not 100" in 30 days).