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Given the dry soil conditions-the hot spots could maybe do upper 90's

We’ve had mid to upper 90s heat waves in May before, that’s not unprecedented. It also might be for just half this subforum since a lot of it looks southerly wind driven. Maybe we get another crazy Ambrose Jet day or two in this and the immediate south shore can’t get above 70.

Steady small dropout rains. My favorite kind. Good for the lawns and gardens.

Thought we might see the Middle of the month get more active into our parts,that seems to be slip sliding away,like the old Paul Simon song would say. Its not like its not been a active year so far.Still seems kinda weird how Wisconsin has had as many tornadoes this year as Alabama and yet Illinois and Miss has give or take almost 40% of all tornadoes this year so far.Oh well,its called weather, right?

62 and full sun. Best climo.

We’ve been wetter than that. CON had 2.49” coming into today. I had 1.31” here.

Had 0.20" 6 PM thru now, one blip of color might hit us for a few cents. Coming home from BGR we saw dark clouds ahead as we left I-95 in Newport. Adjusted the wipers about 30 times in 45 miles after that, mainly between interval and stop (don't like the squawk of wiper vs. dry glass). Forecast for this aft, tonight, tomorrow - less than 0.1" thrice, even with PoPs of 60/60/80%. The 1-2" is staying west and south.

Yeah, it might be hot. I think we will survive. Its been 90 already this year and we pulled through.

Does this pretty much describe your conditions for the year?

The heavy rain is legit just hanging out 2 miles to the west. What a tease

Now saturate

0.03". Hope we get slammed tonight, otherwise bust

Dave, is that you?

Soaking drizzle almost all day in Greenfield. I wish we could trade weather.

Quite the difference my NWS point and click had the warmest being Tuesday and only 87 degrees...Enola has 94 on Tuesday

What an absolutely exquisite day, in an otherwise cooler and wet May.

Backyard is swamped. Love it. 54° +RA

Looks like we stein here. Rain will be fairly brief. The spring of stein.

Many models steined his area to you. Spring cutoffs usually not handled well.

Geez might get up to 95 on Monday now. Pretty insane to see in mid May. Also with how cold its been for a while it's just going to make it feel that much hotter

I sit at a dismal 9.74" of rain for the year which puts me at about the 21st percentile Sent from my SM-S731U using Tapatalk

Winter 2025-2026 Offered Return to Normal As Advertised And Then Some Strong Forecast Overall Leaves Room for Improvement Primary Sensible Weather Winter Analogs (*Denotes Strongest Analog): 2024-2025, 2021-2022, 2017-2018, *2000-2001, 1970-1971 The narrative surrounding the 12th annual Eastern Mass Weather winter outlook issued this past November, which was aptly titled "Winter 2025-2026 Offers Return to Normalcy" , was that the region would experience a return to a more traditional southern New England winter, as opposed to the very mild recent run of seasons that we have been experiencing over the past several years. This pattern is very evident when viewing a composite of the last 7 winter seasons prior to winter 2025-2026, which features a very predominate eastern ridge. Not only has this period been very mild, but it has also unsurprisingly featured a notable snowfall deficit, as the mean snowfall in Boston during the period is just 26.6", which is roughly half of the long term average. In fact, some locales just to the north of the greater Boston area had gone seven consecutive seasons with below average snowfall. Even Boston itself recently recorded the third longest snow drought in recorded history at Logan International Airport, narrowly falling short of the second longest drought of 2006 by a mere two days. Graphic Courtesy of NBC10 Meteorologist Pamela Gardner Indeed, this shorter-term streak was halted at 301 days by a festive snowfall of 1.3" on December 14th, however, it was the 61.5" that followed over the course of winter 2025-2026 that ultimately delivered the advertised "return to normalcy", and in so doing ended a longer-term streak of overall winter futility. Perhaps the question of whether or not this departure from recent history represents at least somewhat of a longer term shift towards more traditional southern New England winters is a topic worthy of consideration. However, before even entertaining of what this shift may or may not portend over the longer term, it's crucial to understand the pattern that winter 2025-2026 deviated from. This of course entails a firm understanding of why the previous several winters were so mild and featured such a dearth of snowfall. The obvious short-answer as to why these recent winters were so lackluster when viewing the graphic above is the behavior of the convective pattern known as the Madden Jullian Oscillation (MJO), which has spent an inordinately large amount of time in the Maritime continent phases of 4-7 that tele connect to a mild pattern across much of the east. Given that the MJO is fueled by the warm waters throughout the equatorial region of the globe, the largest body of water on the planet is a prudent place to begin when considering why it has behaved in this manner so persistently . Oceans are the Earth's "Heat Sink" The warming that we have experienced on land while going about our daily lives over the course of the past few decades is certainly the most obvious manifestation of climate change. Note that temperatures have been running upwards of several degrees above the longer-term baseline in areas of the US. Although the US is the point of focus within this particular context, this of course, is not a phenomenon that is relegated to just the US, or North America for that matter. In fact, the average temperature has risen 2 degrees F on a global level since the late 1800s due to greenhouse gas from anthropogenic emissions impeding the ability of heat to escape out into space as liberally as it used to (NOAA). This creates quite the conundrum since only about 30% of incoming solar irradiance is reflected back into space. The remaining 70% is stored on earth, with 20% being absorbed by the atmosphere, and 50% harbored in the land and sea. The implication here is that less heat is able to escape with time, which means that the surplus of heat in the atmosphere, land and sea is growing, thus accelerating the rate of said warming. This is evidenced by the fact that the rate of warming spanning the 50 years since 1975 is three times that of the warming over the span of the 75 years from 1850 to 1975. Furthermore, 2024 marked the 10th consecutive year that was declared the warmest on record across the globe (NASA), despite the fact that it was widely perceived as having been a relatively cold winter throughout much of the US. The obvious deduction here is that the world is warming at an accelerating rate due to the fact that anthropogenic emissions are causing the roughly 30% of solar heat that is escaping back into space to decline even further, thus increasing the heat surplus. Needless to say, the rate at which said warming is accelerating seems extraordinary enough in-and-of-itself. However, in order to fully appreciate the magnitude and scope of the issue at hand, one must understand that according to NOAA, approximately 91 percent of the warming that has happened on Earth over the past 50 years has occurred in the oceans. This is both because oceans account for about 70% of the surface of the earth, and can absorb more heat without a rise in temperature than land. Thus it is evident why the aforementioned growing surplus of heat has rendered the oceans the largest solar energy collector on earth (NOAA via Climate.gov 2025), which means that they are sure to be instrumental in the modification of weather patterns due to the atmosphere-sea interface. The implication here is that although the warming of the air temperature is the most apparent to the earth's population and is dramatic enough in-and-of-itself, the warmth that we are experiencing actually greatly underestimates the true magnitude of the changes that are taking place, and the degree to which the atmosphere is impacted. Possible Ramifications of Immense Ocean Warmth El Nino Southern Oscillation (ENSO) is frequently referenced at Eastern Mass Weather due to it's crucial role in the distribution of heat around the globe via convective processes, which represent the very essence of the complex system of land, sea and air interaction that dictates weather patterns. The budgeting of heat is the vehicle that drives said weather patterns and is thus the reason weather exists, which underscores the crucial role that oceans play in this process given that they comprise the vast majority of areal coverage on the planet. This means that they have the greatest capacity to store heat by many magnitudes of order more than the land and atmosphere. This is clear when considering how the most pronounced accelerations in global warming have coincided with the most powerful El Nino events. The inference here is that it is crucial to consider the area of ocean that is warming the most, as this will represent the focal point for the convective processes like the MJO that will strive to redistribute said heat in the interest of obtaining a global atmospheric equilibrium. Additionally, once said heat nodes become anomalous enough and of sufficient depth, the feedback between the sea and air can be established and become self-sustaining. The implication here is that SSTS and conditions near the ground can reenforce a given atmospheric regime in the absence of a major catalyst for change. When considering the graphic below, it is apparent that the largest increase in oceanic heat content has occurred in the western Pacific, with a secondary area off of the northeast US coast to the south of Newfoundland. These areas are not coincidental and are likely a byproduct of both the prevailing trades as regulated by the Walker Cycle (West Pacific), and perhaps the melting of sea ice slowing the warming in the higher latitudes (near New Foundland). These maxima of heat content are in areas that correlate with both +WPO and +NAO. Accordingly, there has indeed been an increased tendency towards the DJFM winter period being biased towards +WPO/+NAO in the mean that has been remarkably evident since the major El Niño event of 2015-2016 accelerated the warming. In fact, since 2016, only two seasons have averaged a -WPO (2016-2017, 2021-2022) and just one season has averaged a -NAO (2020-2021). This would seem to imply that this is at least partially attributable to some sort of feedback accentuated by the stored ocean heat content that is most assuredly a byproduct of climate change to some degree. Note the similarity to the West Pacific Oscillation (WPO) correlation map in terms of both temps, as well as the 500mb pattern over the US during the DM period over the course of the past decade, which validates the premise that the west Pacific has been the prevailing catalyst in this pattern of mild winters for the eastern CONUS. While the vast majority of the country has been running above the 1951-2010 climatology base owed to the general background warming, it is clear how the magnitude of said warmth is weighted disproportionately in that it is much more intense across the eastern portion of the country. The eastern half of the CONUS has been running several degrees warmer than average, while areas of the Pacific north west coast hardly at all. This is due at least in part to the aforementioned heat maximum over the west Pacific, which has come to be known as the West Pacific Warm Pool. This immense warmer body of water, which is likely attributable to some combination of climate change and natural variation, has caused the MJO to spend an inordinately excessive amount of time in the maritime continent (MC) phases of 4-7 as a result of the aforementioned tropical convective processes that act to budget and redistribute the immense amount of stored heat around the globe. These, as mentioned, are the phases that correlate with greater heights and warmer weather over the eastern half of the country during the winter season, which is precisely what has occurred in the mean over this span of time, as previously referenced. It is not difficult to discern that the warmth of this era has played a rather large role in the snowfall deficit across the forecast area, however, even colder intervals have often failed to produce significant snowfalls both as a result of unfavorable storm tracks, and failed attempts at phasing. The former is a byproduct of the same southeast ridge that has been driving the warmth, however, failed phasing attempts are often due to a more subtle trend that has acted to mitigate major east coast snowfall threats even during periods of relaxed southeastern heights and sufficient cold. More Active Modern Pacific Jet Inhibiting Major East Coast Snowfalls Eastern Mass Weather has asserted that another byproduct of the rapidly warming western Pacific is an increasingly prominent jet that is being driven by the ever growing gradient between the warmth in the vicinity of Japan, and the consistent cold over Siberia. Note the increase in the strength of the jet over the past several decades, which has accelerated over the past 20-30 years with the increasing rate of warming in the western Pacific. This has a tendency to interfere with opportunities for major snowfall along the northeast coast by disrupting and delaying the phasing of the southern and northern branches of the jet stream, which can result in substantial snowfall deficits throughout the east even in the absence of prohibitive warmth. Here is a composite of two seasons over the course of the past seven years that has near normal or even slightly below average temps, yet each season featured decidedly below normal snowfall across the region. Obviously the lack of snowfall is at least somewhat attributable to unfavorable storm tracks as a result of the aforementioned consistent southeast ridge presence. However, what is also evident in each of these respective seasons is the tendency for one branch of the jet to be very powerful and overbearing, which negatively interferes with phasing attempts. Here is one such example from January 2025. In contrast, the composite of snowiest seasons throughout Boston's recorded history features dual jets that are much more diffusely defined, and thus more conducive to interaction with one another and subsequent phasing. In summary, the faster rate of warming throughout the western Pacific relative to the rest of the basin has resulted in a persistent pool of anomalously warm waters just to the east of Japan, which has not only biased the hemisphere towards a +WPO/cool ENSO paradigm, but has also excited the Pacific jet as a result of the gradient between the cold over Siberia and the warmth to the east of Japan. Both of these factors have worked in conjunction with a secondary area of accelerated warming just southeast of New Foundland to promote a persistent +NAO pattern, which also favors more inland storm tracks and flawed attempts at phasing. While there is a school of thought that these changes are more permanent, the inference from Eastern Mass Weather last fall was that the influence of this west Pacific warm pool would begin to wane, allowing for more substantial deviation from the MC regime that has been so prevalent for the past decade, hence the assertion that Winter 2025-2026 Offers Return to Normalcy. Now that a proper context has been provided, the process of evaluating how this premise fared can begin. Eastern Mass Weather Past Results The mean forecasting error for each of the twelve seasonal snowfall outlooks issued are as follows: Twelve Season Mean: 167.3% 2025-2026: 24.1% 2024-2025: 12.3% 2023-2024: 120.3% 2022-2023: 900.6% 2021-2022: 36.2% 2020-2021: 14.1% 2019-2020: 678.3% 2018-2019: 90.3% 2017-2018: 13.2% 2016-2017: 35.3% 2015-2016: 71.4% 2014-2015: 10.9% The twelve season running mean error dropped from 180.3% to 167.3% after this last effort. The worst snowfall forecast was issued for the 2022-2023 season, which had a ghastly 900.6" average forecast error. The historic 2014-2015 season represents the most accurate snowfall forecast, with a mean error of just 10.9%. While the mean forecasting error is 167.3%, 5/12 seasons have had an average error of under 25%. 38/176 (21.6%) of snowfall outlooks have been under forecast. 104/176 (59.1%) of snowfall outlooks have been over forecast. 34/176 (19.3%) of snowfall outlooks have verified within the forecast range. Below are forecast seasonal snowfall totals versus verified amounts for the fifteen select Eastern Mass Weather cities throughout the northeast and mid Atlantic regions. City Predicted Snowfall for 2025-2026 Actual Forecast Error Boston, MA 44-54" 62.8" 16.3% NewYork, NY(Central Park) 19-29" 43.4" 49.7% Philadelphia, PA 14-24" 30.1" 25.4% Baltimore, MD 8-18" 15.6" Verified Washington, DC 6-16" 10.6" Verified Albany, NY 64-74" 58.4" 9.6% Hartford, CT 44-54" 52.7" Verified Providence, RI 33-43" 69.3" 61.2% Worcester, MA 70-80" 79.4" Verified Tolland, CT 55-65" 70" 7.7% Methuen, MA 60-70" 71.75" 2.5% Hyannis, MA 10-20" 46" 130% Burlington, VT 96-106" 82.4" 16.5% Portland, ME 81-91" 63.7" 27.2% Concord, NH 67-77" 58.3" 14.9% The mean snowfall forecasting error for the 2025-2026 winter season throughout the 15 locales was 24.1%. Total seasonal snowfall verified within the forecast range in 4/15 cities, and was within 10% of the forecast range in 7/15 cities. This was the fifth most accurate forecast amongst the twelve seasonal efforts in terms of mean forecasting error, and caps off the most accurate two-year run to date. While the effort can undoubtedly be deemed as a success overall, it was by no means perfect. Winter 2025-2026 Slightly Snowier & Colder Than Forecast The overall pattern for winter 2025-2026 can best be categorized as "cold and dry". Note that while the forecast composite below (left) was reasonably accurate qualitatively speaking, as compared to reality (right), it was not quantitatively dry enough across the southeastern half of the US and up through the northeastern corridor. Temperatures throughout the mid Atlantic and southern New England regions for the December through March forecast period verified generally near normal to about two degrees below average, as compared to the forecast range of near normal to two degrees above average. This slightly colder and drier pattern relative to the forecast was the result of a mean polar vortex that was oriented in a more northwest to southeast trajectory across Canada, as opposed to southwest to the northeast orientation that was forecast. Note that the blocking ridge in the west-central Pacific was more pronounced and shifted slightly eastward relative to the forecast composite (left), which acted to amplify ridging over the southwestern CONUS that pinched the PV off and oriented it more northwest to southeast in reality (right), as opposed to northeast to southwest in the forecast composite. This configuration is ostensibly a strong -WPO pattern that acted to channel cold more into the northeast CONUS and southeastern Canada, rather than the intramountain west, as suggested in the forecast composite. However, the fact that it did not calculate as such is a splendid illustration of the limitation of using precise index calculations to characterize something as chaotic as the atmosphere. Imposter Western Pacific The consistent flow of colder and drier continental, even arctic air on occasion, resulted in snowfall being slightly over forecast for the four locales throughout northern New England and the distant interior. This error ranged from 9.6% in Albany, NY to upwards of 27.2% less snowfall than forecast in Portland, ME. Conversely, the consistent cold acted to bolster snowfall relative to the forecast for the seven cities closer to the coast, where snowfall is more heavily correlated to temperatures. Across this corridor, snowfall ranged from 2.5% greater than forecast in Methuen, MA to as much as 130% in Hyannis, MA on cape cod, where ocean effect snows also contributed during arctic outbreaks. Essentially, the more robust WPO dyad being displaced eastward ultimately elongated the PV from Alaska towards the northeastern US in the precise same manner that a -WPO pattern would, which shifted the maximum positive snowfall anomalies to the coastal plane, as opposed to the slightly milder forecast that focused the heaviest snows over the interior. The PV being extended in a northwest to southeast direction allowed for lower heights to prevail in Alaska, as evidenced by the mean DJFM EPO value finishing positive, at .42 rather than the -20 to -50 range that was forecast under the presumption of a southwest to northeast oriented PV (intramountain west into the North Atlantic). Thus the error within the EPO domain was to be expected given the pattern of lower heights extending into Alaska. However, it as the DJFM mean WPO value of .44 verifying slightly more positive than the forecast range of .02 to .32 that was counterintuitive. Index Value Predicted '25-'26 DM Value Range Actual '25-'26 DM Value Forecast Error Pacific Decadal Oscillation (PDO) -1.46 to -1.76 -.81 Biased .65 Negative Perennial North American Pattern (PNA) -.08 to -.38 -.73 Biased .35 Positive ENSO OND -0.7 to -0.9 ONI EMI: -.4 to -.6 (Mixed-Type) OND -0.6 -0.6 Biased 0.1 Cold Verified (J-M) East Pacific Oscillation (EPO)/DM West Pacific Oscillation (WPO) -.20 to -.50 JM EPO .02 to .32 DM WPO .42 JM EPO .44 DM WPO Biased .62 Negative Biased .12 Negative Arctic Oscillation (AO) -.14 to -.44 -.25 Verified North Atlantic Oscillation (NAO) .04 to .34 .59 Biased .25 Negative This discontinuity is a consequence of the northern Pacific ridge node failing to fit neatly within the domain of the WPO index calculation, which is an unfortunate shortcoming of this methodology that is all too common. Below is a juxtaposition of the Pacific basin SST composite for the DJFM 2016-2025 period, which featured a very +WPO, and last season. What is evident when comparing the SST composites above with the SST composite for the WPO SST correlation below is that the 2016-2025 period (left) had the heart of the warm pool precisely where it is most highly correlated to the +WPO regime. However, although it was generally representative of a -WPO configuration last season (right), it was shifted slightly west relative to the area of negative correlation in the Gulf of Alaska on the chart below. This particular placement of the North Pacific warm pool seems to be consistent with east-ward leaning, basin-wide cool ENSO events, such as the one during the 2025-2026 winter season, which peaked during the OND tri-monthly period, as forecast, albeit with an ONI (-0.6) slightly weaker than the forecast range of -0.7 to -0.9. Accordingly, northwest to southeast orientation of the elongated PV in the seasonal mean is consistent with both the weak and east-based La Niña data sets. Incidentally, the last -WPO winter occurred during an east-based La Niña season during the winter of 2021-2022, which also had the last latter January major winter storm. This distorted WPO signature in the SST anomaly profile last winter was also evident in the 500mb pattern. Here are 500MB composites for +WPO (left) versus -WPO (right). It is clear that the 500mb pattern last season much more closely resembles the -WPO composite, however, the ridge node was displaced slightly to the southeast. The discrepancy is also evident in the DJFM 500MB correlation to the WPO. Note the similarity to both the east-based and weak La Niña composite with respect to the placement of the North Pacific -WPO dyad, which triggers the SW CONUS ridge that encroaches on the PV and pinches it into an elongated northwest to southeast orientation from Alaska over into the northeast CONUS and southeastern Canada. Elongation of PV NW to SE is Common in Weak & East-Based La Niña This is a perfect illustration of the limitations of index calculations, as a DJFM pattern that is clearly more redolent of a strong -WPO configuration was recorded as a modestly positive value. The implication of this is that although the Eastern Mass Weather premise of a translation of the warm pool eastward, and a relaxation of the strong +WPO/+NAO regime of the last decade proved accurate, the correction was even more pronounced than anticipated. Furthermore, weighting the ENSO Modoki dataset more heavily would have improved the forecast, as it would have more accurately conveyed the precise orientation of the PV that was so crucial to the consistent supply of cold to the northeastern US despite a modestly positive mean DJFM WPO value. The fact that the strongly negative DJFM mean PNA value of -73 verified significantly more negatively than the forecast range of -.08 to -0.38 is a testament to just how prominent of a player this WPO pattern was in the hemisphere this past winter. This theme became established very early on in the winter season. Stealthy -WPO Emerges & December Colder Than Forecast As East-Based Nina Dominates December Review December Analogs: 2021, 2017,2008, 2007, 2000, 1981, 1970 The month of December featured near normal to slightly above normal snowfall throughout the majority of the region, although some areas near the coast finished slightly below average given that the month was not as active as anticipated. Although the rate of storm's was not as frequent as theorized, the region's first widespread snowfall did in fact occur near the end of week two, as implied by the analogs in the winter outlook. The month behaved largely as expected in terms of the evolution of the pattern, primarily owed to the similarity of the anticipated deviation from the predominate Maritime Continent forcing of the past decade, to the analog periods of December-January 2017-2018 and 2024-2025. December 2025: December 2017-January 2018: December 2024-January 2025: However, the magnitude of the negative temperature departures throughout the month were much more extreme than forecast, by approximately 5 degrees F, as the range across the region is between about -4 to -6F, as opposed to -1 to +1F forecast. This is largely due to the extreme Bering Sea blocking (-WPO) that was observed (-3.48 WPO peak on 12/13), which also amplified the positive anomalies that were expected across the western CONUS. This pattern set the trend for the rest of the season in that the strong -WPO configuration was biased east and was thus not reflected by the .08 monthly value. Another nuance that carried over throughout the vast majority of the season was that the magnitude of the mean WPO was so extreme that it entirely negated the consistently negative RNA, which averaged -1.41 for the month of December, that was anticipated to modify the colder pattern throughout the northeast to an extent. Note the similarity of this strong -WPO configuration that calculated as slightly positive to the seasonal pattern, which also calculated as slightly positive. This extreme -WPO block that set the tone for the season is also likely at least in part why the pattern remained drier than expected, as northern stream clippers were the predominate storm type as opposed to the anticipated SWFEs given a dominate northern stream. There were also additional idiosyncrasies with regard to the polar domain during the month of December that conspired to bias the forecast consistently colder than expected, despite a fairly well forecast upper level pattern, which appeared to have ramifications that reverberated through the entirety to the winter season. Behavior of the Polar Domain During December The polar vortex disruption that occurred near the end of November was similar to the December 4, 1981 alternative scenario that was laid out last fall in that it barely managed to trigger a full 850MB zonal mean wind reversal in the arctic, where as the 2000 event missed by a narrow margin. Thus it was slightly more significant than the December 2000 analog event, and consequently ended up playing a more instrumental role in the mid winter pattern. However, the vortex still recovered to something approaching climo levels by the holiday week, as forecast last fall per research conducted Lee et al (2019), which indicates that the arctic high regime is favored for less than 20 days following a weak PV (roughly November 28th). This despite the insistence of initial modeling and social mediaologoists alike that it would remain weak through the new year. This consistent recovery of the PV following the major disruption near the end of November did in fact result in a reprieve from the high latitude blocking by mid-December, as forecast, however, the blocking unexpectedly rematerialized over the course of the last week given that the troposphere remained uncoupled from the recovering stratospheric polar vortex. The hostile polar domain during the mid-month interval in conjunction with lowering heights on the west coast, as reflected by a descending PNA value, did in fact allow the storm track to shift west just in time for the forecast "Grinch Storm" to materialize, which eradicated all of the snowpack throughout southern New England. This event was indeed similar to periods prior to the Christmas holiday in the referenced analog months of December 2007 and 2008, especially the former. However, there were nuances with respect to the Polar vortex that acted to mitigate these warmer interludes. First of all, it was consistently stationed not only on this side of the hemisphere, but as nearby as southeastern Canada throughout the month of December, which in conjunction with the potent Bering Sea ridge ensured that the mild intervals were always shorter in both duration and magnitude than the colder intervals given that the cold air source was always so readily accessible. This represents a major reversal from the last decade or so, generally speaking. Additionally, by the time the stratospheric vortex had recovered to climo levels and beyond as the holiday period approached, the lagged impacts from the latter November reversal ensured that it remained uncoupled from tropospheric vortex, which allowed the blocking to redevelop, further attenuating what was expected to be a prolonged stretch of milder weather across the northeast. This was especially evident during the late portion of the month, which acted to mitigate the moderation of the pattern despite the development of the expected Pacific trough regime. Mid-Month Pacific Trough Transition Well Forecast There was a battle waged throughout the holiday period, as the MJO remained shallow and variable as high latitude blocking reestablished, while the Pacific Trough regime asserted itself right on schedule. Note the disparity between the first and second half of the month. Intervals of high latitude blocking thwarting efforts of very mild, Pacific air masses centered in the nation's mid section from reaching the northeastern CONUS would go on to become another very prevalent seasonal theme throughout meteorological winter. The first half of the month was remarkably similar to the aforementioned MC mismatch analog periods. And the latter half baring a striking resemblance to the Pacific trough data set, despite not being mild across the east in the mean due to factors previously discussed. Be that as it may, the development of this Pacific trough regime during the middle portion of December further evinced one of the premises of the Eastern Mass Weather winter outlook from last fall in that the MJO would continue to struggle to accrue residence time in phase 8 because of the west Pacific warmth. This was indeed been the case during the early portion of the season. The consistent struggle for the MJO to remain a coherent wave in the western Pacific has been a pattern over the course of the past decade that any seasoned forecaster should not have neglected to consider. The disjointed signal resulted from the continuation of the battle for proxy between the MC and western Pacific, which allowed for an occasional element of western Pacific expression to assert itself into the pattern as a byproduct of the areas of dual forcing. This was especially prevalent during the final week of the month and would be a recurrent sequence throughout the winter, as arctic intrusions managed to periodically infiltrate the northeastern quarter of the country and limit what would have otherwise been a mild period in the mean during these Pacific trough regimes. The final sequence of 2025 was a prime example of this, as the final system to impact the area just prior to the new year drove west of the region and induced a warming southwest flow. However, the warm up was met with resistance from antecedent cold, which produced a period dangerous icing before the surge of warm air transitioned precipitation over to plain rain. The departing storm was then rapidly followed up by yet another invasion of arctic air during the first few days of January. The Pacific trough pattern that heralded in the new month and new year was crucial to the seasonal forecast because it was anticipated to trigger a chain of events in the stratosphere that would ensure that the latter portion of the season would be anything but characteristic of a typical cold ENSO season. However, these impacts ultimately coupled with the residual aftermath of the latter November zonal wind reversal of the PV to bias the month of January colder than expected. December Review: Mid January Stratospheric Reflection Event Key to Stormy & Bitter Latter January January Analogs: 2025, 2018, 2014, 2002, 2001, 1971 Society's understanding of the stratosphere and the role that it plays in modulating our weather is very rudimentary to say the least. The basic conceptualization is that a weak polar polar vortex makes the mid latitudes more prone to cold outbreaks, and while that is true, the method of delivery for cold to North America is multifarious in that it is not relegated to a weak polar vortex/-NAO pattern. In fact, the coldest outbreaks in the CONUS are actually triggered by a polar vortex and +NAO regime in what is referred to as a "stratospheric reflection event". During these stratospheric reflection events, heat is transferred upward by a Rosby wave (kink in the jet stream) over Siberia and reflects back downward of off the PV into Canada via the reflective surface represented by negative vertical wind shear in the stratosphere. ( Lee et al 2019). The study notes that these reflection events are most common during the month of January and played an instrumental role in the forecast for the mid-winter +TNH pattern. There is one reflection event on average each season, so they are by no means rare events. Reflective events are declared when the reflection index (RI), which denotes the difference in anomalous poleward eddy heat fluxes in the lower stratosphere between Siberia and Canada, exceeds 1 for 10 or more consecutive days (Lee et al 2019). Reflective events are unique occurrences in that the PV is undisturbed and initially remains strong, before being stretched by the development of Alaskan and Aleutian ridging and returning to normal strength. This is why the potential time-lagged, disruptive impact of the November 28th zonal wind reversal on the troposphere was so vital to pairing the redevelopment of high latitude blocking with the latter January +TNH interval to exacerbate the resultant severe mid-winter intelrude. It is the stretching that delivers the cold south and eastward into the CONUS, as depicted in the "end of event" graphic above. This type of stratospheric phenomenon differs from the SSW events, in which heat propagates upward in waves that converge in the stratosphere, thus weakening the PV by decelerating and even reversing the zonal westerly winds that are ordinarily prevalent in the polar stratosphere. Reflection events also differ from SSW in that they are more favored during the westerly phase of the QBO, with 30/44 events since 1980 having occurred during a +QBO. While this ostensibly rendered such an occurrence unlikely last winter given the very strong easterly QBO that was nearing peak, the analog events of January 16, 2001 through February 18, 2001, and January 13, 2018 through February 2, 2018 were weighted heavily in the seasonal forecast given their strength as general analog seasons due to considerations discussed last fall, such as polar, ENSO and solar implications. This is also why these two seasons were considered superior SSW analogs during the month of February. Here is a list provided by Lee at al (2019) of the most prominent reflection events of the past 45 years, including the primary analogs of 2001 and 2018. Courtesy Lee et al 2019 Note that the mean length of the process is 20 days, with 10 days being the minimum, and 60 days the maximum, per Lee et al (2019). The length of the 2001 (33 days) and 2018 (20) events were considered in the forecast for a reflection event to begin between approximately January 13th and 16th 2026, and end between about February 2 and 18th, which is consistent with the climatologically favored time frame per the research that was referenced previously. It is clear that this indeed took place as forecast given the feed back from Judah Cohen. "And as I have been routinely doing, looking at the wave diagnostics in Figure iv continues to display wave reflection over the weekend and into late January. For both periods shown, wave energy goes up and east over Asia, reflects off the stratospheric PV and then heads down and east over North America where the energy is re-absorbed and could potentially amplify the standing wave over North America and deliver cold air from the Arctic south, east of the Rockies. There is westward wave tilt with height over Asia and an eastward wave tilt with height over North America that is a classic signature of wave reflection. Though the eastward tilt is more pronounced in the first period compared to the second period". In order to better understand how the PV interacts with North American weather, Lee at al identified four distinct weather regimes and listed their respective frequency of occurrence between the months of November and March, from 1979 through 2017, since they last longer than synoptic scale patterns and thus provide an opportunity for longer range prediction. January Review New Year Pacific Trough Pattern Precursor for Mid January Reflection Event Pattern recognition is paramount in the analysis and diagnosis of reflection events because the behavior of the polar vortex has predictive value on each of these regimes at both seasonal, and sub-seasonal leads, which is roughly 15-60 day in advance. "The PV strength significantly affects the occurrence and persistence of each regime and transition between regimes" (Lee at al 2019). Research by Kretschmer et al (2018) illustrated the importance of planetary wave reflection for anomalous cold across North America. This expounded on earlier work by Kordera et al (2016) that found that wave reflection born of Pacific blocking tele-connected to a down stream trough over North America. Thus the implication here is that the Alaskan ridge pattern, which is not at all connected to the PV and is actually accompanied by a +NAO, as alluded to earlier, is most conducive to reflection events and is thus correlated to the most severe arctic outbreaks in the US. Lee et al (2019) refers to this type of pattern as the "Alaskan Ridge Regime" , which is similar to the positive phase of the Tropical/Hemisphere Pattern (+TNH). The +TNH pattern, which has been referenced previously in this writing, is marked by higher heights over the Gulf of Alaska, the Gulf of Mexico and over the southeastern US and into the western Atlantic. Below average heights are normally anchored over southeastern Canada in association with a vortex buoyed between the Great Lakes and Hudson Bay, which is precisely what took place during the latter portion of January. Note the similarity to the January 2014 analog. This particular pattern was cited last fall as the most common vehicle for cold delivery over the past decade given the increased tendency for +NAO during the winter season, which underscores the fact that climate change is certainly not prohibitive to severe cold outbreaks. That disclaimer certainly seems to have been validated based on the magnitude of this mid-winter arctic outbreak. This is not at all surprising based on past +TNH episodes. Here is a composite of seasons that fit this +TNH description over the past decade or so. The implication here is that there was an increased likelihood for both anomalous cold outbreaks, and deviation from the predominate MC regime of the past decade during winter 2025-2026, which was also outlined last fall. Here are the four regimes as defined by Lee, accompanied by the spacial pattern of the temperature anomalies that accompany them. The Pacific trough regime (31.6%) is the most frequent, followed by the Alaskan ridge pattern (25.1%). Below is the composite for the Pacific trough regime, which is akin to the extra tropical Pacific +EPO regime. This composite contains the Eastern Mass Weather extra tropical Pacific analogs of 1950-1951 and 2001-2002, as well as the La Nina analog of 2005-2006. Note the similarity to the mild interval during the middle portion of the January that was initially poorly modeled. This portion of the seasonal forecast evolution was predicated upon research by Lee et al (2019), which identified the transition from this Pacific trough regime to the Alaskan ridge regime as most conducive to the type of wave propagation needed to trigger a reflection event. This is what renders the Pacific trough regime the precursor to the stratospheric reflection necessary to trigger the +TNH pattern that teamed with the reemergence of high latitude blocking to ultimately deliver an absolutely brutal stretch of winter to the region during the latter third of January. This proved to be a remarkable extended forecasting tool given the expectation for a mid January onset of a reflection event that coincided with an influx of mild Pacific air. Note that the pattern begins to reverse in earnest approximately 5 days after the event onset, which is precisely what took place. Simultaneously, the anonymously strong PV, which uncoupled from the troposphere, reverted to normal strength, and began to stretch due to the building Alaskan and Aleutian ridging that retrograded from North America. In addition to the return to climo strength and above, the stretching of the PV during this reflection event was also very evident. Although the pattern progression for the first half of January evolved largely as expected, the return of -NAO blocking in conjunction with the development of the expected +TNH pattern during the latter third of the month was a notable deviation from the forecast. As it turned out, the seeds for the return of high latitude blocking on the heels of the mid-month interval of +NAO that accompanied the Pacific trough-fueled thaw may have been planted at the very onset of meteorological winter, as hinted at earlier. Latter November Reversal May Have Triggered -NAO Flavored +TNH Pattern It is evident in the annotation below that rather strong NAO blocking rematerialized after the milder period centered on mid-January. This is also on full-display in the monthly 500mb pattern, which has far more blocking within the NAO domain than expected. This resulted in the PV being displaced slightly lower in latitude relative to the forecast, which is in large part why the month ended up somewhat colder than expected throughout the northeast (-1 to -3F Instead of +1 to +3 Forecast), despite a superb overall pattern diagnosis. This also helped to ensure that the deeply -AO was perhaps even more prominent in the monthly mean relative to the forecast. It was mentioned previously that the polar vortex disruption that occurred near the end of November was similar to the December 4, 1981 alternative scenario that was laid out last fall in that it barely managed to trigger a full 850MB zonal mean wind reversal in the arctic, where as the 2000 event missed by a narrow margin. Thus it was slightly more significant than the December 2000 analog event and had a better chance at downward propagation into the troposphere, which it appears ultimately took place. The November 28, 2025 reversal joined the previously referenced December 4, 1981 event, as well as the November 27, 1968 and November 30,1958 episodes as the only four latter November/early December polar zonal wind reversals on record. The latter two were not referenced in the winter outlook last fall because they were accompanied by El Niño events. Here is the January composite following those three respective events. Considering that research supports a longer lag time of up to 40-45+ days for stratospheric warmings this early to propagate into the troposphere, the 49 day lag between the November 28th reversal and the approximate onset of the rapid descent of the NAO around January 16 renders this a viable explanation for the return of latter January blocking. Another unique flavor to this particular +TNH episode that was foreseen in last fall's winter outlook was its' co-occurrence with a predominately +PNA interval, which would validate the premise from last fall that the month of January would be the lone month of deviation from an otherwise RNA season. Emergence of Western CONUS Ridging Key In More Active Pattern Guidance was originally insistent that the RNA pattern from the month of December would persist throughout the vast majority of the month of January, with the exception of a brief interval of PNA flex the second week of the month (10th-15th). The above annotation ultimately proved correct in asserting that the forecast return of RNA after mid-month, as suggested by guidance, was in fact erroneous. Eastern Mass Weather used history as a guide last fall in positing that the consistently negative PNA values from December would give way to a positive PNA in the mean during the month of January, as per the expected deviation from the cool ENSO oriented Maritime continent forcing. December 2024-January 2025: This notion was buttressed by data provided by Don Sutherland of Americanwx forums, which indicated that 10/10 -PNA streaks of 35 days or greater during the months of November-December since 1980 have averaged positive over the subsequent 30 day period. Data Courtesy of Don Sutherland It was posited that this represented an integral part of the forecast for the +TNH pattern that would become established during the latter half of January because the addition of a +PNA in this type of pattern would increase the likelihood of a significant, and perhaps even major east coast storm, as opposed to the traditional overrunning type of precipitation events that typically rule these sort of regimes. This was evident during the final week of the month, when the intense +PNA ridging was instrumental in the development of a major snowstorm across much of the northeast much like the east-based La Nina analog of January 2022, despite the fact that southeast heights remained somewhat elevated. The influence of the southeast heights were insufficient to preclude a major northeast snow event due to the impact of the western ridging in conjunction with the southward displaced PV, and western-biased negative NAO block acting to suppress the system enough to remain offshore. It was also suggested that the approach of the MJO to phase 7 at a relatively high amplitude portended a trend towards a more protracted period of PNA that would constructively interfere with and subsequently maintain a +PNA value for the duration of the month. This particular convective forcing regime across the tropical Pacific did indeed prolong the +PNA interval, despite what guidance at the time implied. The progression of the MJO from phase 6-7 at a relatively high amplitude beyond mid month is largely why January ultimately ended up merely subtly drier than forecast, despite well below average precipitation during the -PNA first half of the month, while the MJO was in the MC phase 6. Phase 6 of the MJO in January promotes southeast ridging, which negatively interferes with attempts at east coast phasing through a compression of the height field in conjunction with a vortex over south eastern Canada, and promotes inland storm tracks via southwest flow aloft in the absence of said vortex. The pattern may remain cold if there is a vortex in relatively close proximity, however, major east coast storm attempts are likely to fail, as discussed with respect to the earlier composite of recent seasons that were not prohibitively warm, yet still produced a dearth of snowfall on the east coast during this recent run of MC forcing. This is not the case when a strong MJO wave progresses into phase 7 during the month of January, as it was the case for the final week of January 2026, just prior to the major storm. The behavior of the stratospheric vortex in the annotation above is precisely why it is very mild at the onset of reflection events, during the antecedent Pacific trough pattern, but by ten days post reflection the pattern has reversed and is characteristic of an Alaskan ridge regime (bottom right above). Winter 2025-2026 represents a splendid illustration of why seasonal forecasting is a much more feasible endeavor when a proper diagnosis of the stratosphere is blended with other methodologies given it's tendency to lead the configuration of the pattern on a hemispheric scale. Accordingly, it was posited just beyond mid-month that the general public was poised to learn just how costly the mid-moth January thaw would be, as not only were heating costs going to rise precipitously for the balance of January, but there also existed the potential for heavy snows. This potential was indeed realized, as the region was mired in the midst of a historic and downright brutal stretch of winter that was set in motion by a dual sequence of events over 30 miles above the earth's surface, in the stratosphere, during both latter November and mid January, which conspired to produce a historic week of winter to close the month of January. Indeed, this lesson was on full display; as an exhaustive assessment of the QBO (stratosphere) overlaid onto the solar cycle yielded insight as to how a zonal wind reversal in latter November can team with a mild, seemingly innocuous mid-month January pattern to trigger a relentlessly punishing onslaught of winter. It was also elucidated how the latter January +TNH pattern that punished the eastern US was simultaneously planting the seeds for destruction for the polar vortex during the latter stages of the season. Value Of Stratospheric & Solar Implications In Seasonal Forecasting On Full Display During Latter January-Early February February Analogs: 2025, 2022, 2018, 2014,2008, 2002, 2001, 1971 Sudden Stratospheric Warming Post +TNH Delayed But Not Denied January Reflection Event Ends On Schedule Near the end of January, Eastern Mass Weather reiterated the forecast from last fall, which called for the stratospheric reflection event responsible for the period of +TNH that played such a prominent role in the brutal stretch of winter throughout latter January, to conclude during the first half of February. This particular timetable was based on the following data: "Note that the mean length of the process (reflection event) is 20 days, with 10 days being the minimum, and 60 days the maximum, per Lee et al (2019). The length of the 2001 (33 days) and 2018 (20) events were considered in the forecast for a reflection event to begin between approximately January 13th and 16th 2026, and end between about February 2 and 18th". Judah Cohen, world renowned scientist for his research on the stratospheric polar vortex, confirmed that the reflection event did indeed commence in mid January, as forecast last fall. "And as I have been routinely doing, looking at the wave diagnostics in Figure iv continues to display wave reflection over the weekend and into late January. For both periods shown, wave energy goes up and east over Asia, reflects off the stratospheric PV and then heads down and east over North America where the energy is re-absorbed and could potentially amplify the standing wave over North America and deliver cold air from the Arctic south, east of the Rockies. There is westward wave tilt with height over Asia and an eastward wave tilt with height over North America that is a classic signature of wave reflection. Though the eastward tilt is more pronounced in the first period compared to the second period". The event concluded on roughly February 10th, consistent with the predicted date range of between February 2nd and 18th, which was derived from the 2001 and 2018 analogs. However, by February 10th, it had completely dissipated and shifted to the Eurasian side of the hemisphere. This corresponded quite well with the transition from +PNA back to the -PNA regime that dominated the early portion of winter, as expected, and the cold abated and shifted west. Note how the cold was focused east during the +TNH/+PNA regime through February 10th. The cold was also anchored in place by the unexpected -AO/-NAO from latter January as a result of the stronger stratospheric PV decoupling from the troposphere in response to the latter November zonal wind reversal. Before shifting west following the end of the reflection event and onset of the RNA/+AO/+NAO regime on February 11th. Although the cold shifted west, it was not as severe given the fact that the PV had retreated to Eurasia. While this transition happened early enough to erase the +TNH signature from the monthly mean, the negative height anomalies over the east remained. The forecast for +1 to +3F monthly departures across the region were too warm and instead verified as -3 to -5F. This was due primarily to the residual early month -AO/NAO, as well as the inclusion of the very mild February 2018 and 2002 stratospheric analogs, which was a mistake. This was anticipated before the month of January drew to a close. The unanticipated high latitude blocking during the first half of the month in conjunction with the February 23rd Blizzard is undoubtedly responsible for snowfall being concentrated closer to the coast than forecast this month. Although the composites for the month of February certainly left something to be desired, the diagnosis of the stratosphere as it pertains to the +TNH fueled severe winter pattern from latter January through early February was forecast with absolute surgical precision. This is due in large part to an exhaustive assessment of both the stratosphere and solar cycle in order to glean invaluable insight into the behavior of the polar domain during the winter season. Stratosphere and Solar Implications Were Key A list of QBO and solar analogs was constructed last August when devising a forecast for the polar domain for winter 2025-2026. Here was the list of 50MB QBO analogs as of last July: July 2025 50MB QBO: -2.06 & descending 2021: 2.82 & descending 2017: 5.08 & descending 2012: -8.10 & descending 2007: -8.75 & descending 2005: -8.13 & descending 2000: 3.25 & descending 1974: -3.42 & descending 1970: -8.05 & descending 1962: -3.08 & descending *Note that July 2014 was the third strongest match at .50 & descending. July 2025 30MB QBO: -19.19 & descending 2021: -13.17 & descending 2017: -10.48 & descending 2012: -27.82 & descending 2007: -24.92 & descending 2005: -24.20 & descending 2000: -13.13 & descending 1974: -19.58 & descending 1970: -18.62 & descending 1962: -15.49 & peaking *July 2014 was the strongest match at -19.29 & descending. Here is an updated list as of October from the winter outlook: October 2025 50MB QBO: -6.83 & descending 2021: 0.59 & descending 2017: 1.72 & descending 2012: -10.51 & descending 2007: -11.52 & descending 2005: -12.28 & descending 2000: 1.51 & descending 1974: -9.69 & descending 1970: -13.48 & peaking 1962: -5.32 & descending *October 2014 was the third strongest match at -2.33 & descending. January 2015 remains a very close match to January 2026 at the 50MB level: January 2015 -9.95 & descending versus January 2026 -9.89 & descending October 2025 30MB QBO: -24.65 & descending 2021: -19.14 & descending 2017: -16.79 & descending 2012: -24.51 & ascending 2007: -29.05 & peaking 2005: -28.76 & descending 2000: -14.04 & peaking 1974: -23.12 & ascending 1970: -22.12 & descending 1962: -15.33 & peaking October 2014 was the second strongest match at -23.86 & descending. January 2015 remains a very close match to January 2026 at the 30MB level: January 2015 -26.70 & descending versus January 2026 -25.52 & ascending The 2014-2015 season was not included as an analog due to the fact it was a warm ENSO season, however, not only was it an elite QBO analog, but it was also a very strong solar analog. This makes it a fine polar analog, and thus it is no secret why it was included in the +TNH composite used in the winter outlook last fall. Here is the ground truth, which evinces how similarly the respective +TNH intervals from latter January through early February behaved. It is not at all surprising that many southern New England sites have also endured their snowiest seasons since the 2014-2015 winter, as the similarities in the respective 500mb patterns during the January 20th through February 10th +TNH interval is evident. Note the key difference being the NAO blocking during this past winter season, presumably as a result of the late November zonal wind reversal within the stratosphere of the polar domain, which did not occur in 2014. This was to be expected given the Eastern Mass Weather polar analog composite from last fall, which also accurately portrayed the northwest to southeast orientation of that PV that consistently channeled cold into the northeastern CONUS throughout the DJF meteorological winter period. The primary difference between the 2014-2015 and 2025-2026 +TNH intervals is not only that the latter included NAO blocking while the former did not, but also that 2014-2015 was occurred a bit later in that it was January through March. The fact that the anticipated early to mid February stratospheric warming did not result in a reversal, and was relegated to a mere Canadian warming had major consequences for the month of March that all but ensured this season would not have the bitter finish that 2015 did. March Warmer Than Forecast Due to Failed February Reversal Mild, Zonal Pacific Flow Interrupted by Periodic PV Stretching as La Nina Decayed Westward March Analogs: 2023, 2022, 2018, 2014 2013, 2008, 2006, 2001, 1996, 1971 Forecast Flaws There were two primary issues with the Eastern Mass Weather forecast composite for the month of March. First of all, the obvious issue is that the month was much warmer than anticipated nationally, with upwards of +10F departures over the southwest, as opposed to the +2 to +3F depicted on the forecast composite. Locally, the disparity was much less pronounced, as southern New England finished within the +2 to +4F departure range in contrast to the -2F to near normal that was forecast. The forecast was acceptable qualitatively speaking, since the southwest was warmest, but it was simply far too cold. The forecast composite was also too wet, with the notable exception being the great lakes and Pacific Northwest. The former being due in large part to a duo of major winter storms mid month, which produced blizzard conditions over a large portion of Michigan and Wisconsin. An active Pacific jet was the driving force behind the precipitation surplus across the Pacific Northwest. It also served as the impetus for the much warmer than anticipated monthly temperature departures nationally given that the polar stratosphere did not evolve quite as anticipated near the end of the season. Polar Stratosphere Less Impactful Than Expected Amid Zonal Flow and Decaying La Nina Two of the most prominent seasonal, and monthly (March) analogs identified last fall were the 2000-2001 and 2017-2018 seasons, which each featured a Sudden Stratospheric Warming (SSW) and accompanying reversal of the polar zonal winds on February 11th and 12th, respectively. This set the stage for the historic barrage of major winter storms to impact the region that followed throughout the month of March in both instances. While the latter portion of winter 2025-2026 did in fact include a blizzard (February 22-23) and zonal wind reversal on March 4th, the forecast timeline obviously differed somewhat from reality. Clearly this entailed that there was not a major winter storm between March 1-15 as outlooked last fall, and more importantly, potential impact from any polar disruption would be delayed relative to forecast, since the anticipated zonal wind reversal in mid February ultimately verified as a mere Canadian Warming, as discussed previously. This allowed any residual high latitude blocking from latter February to rapidly relinquish it's grip near the onset of the March, which acted to truncate any colder intervals resulting from spasmodic episodes of PV stretching throughout the month. Here is the first such instance early in the month. Note how quickly the PV is allowed to retreat in the absence of blocking, leaving rapid warming amid zonal, Pacific flow inundating the nation. This was not the case throughout the vast majority of meteorological winter given the residual impact of the latter November reversal, which rejuvenated blocking from mid January into mid February, which acted to pin the PV in place for a much longer interval of time. The stratosphere constructively interfered with the weak-east-based La Nina throughout the meteorological winter period of DJF to ensure that the warmth to the west was largely held at bay in in the composite mean. The resemblance between meteorological winter and the east-based La Nina data set is apparent. Concurrent with the early March stretching of the PV, the anticipated reversal of the zonal winds and accompanying split of the PV was finally observed on March 4th, approximately three weeks behind schedule (forecast). The implication of this delay, of course, is that it would have no impact on the polar stratosphere during the month of March, and thus it was able to recover quickly after each of it's periodic stretches. The lack of any hemispheric driver within the polar domain given the failed February reversal left a La Nina that was rapidly decaying into more of a Modoki configuration to constructively interfere with the development of a strong Pacific trough regime, which resulted in record warmth about 7-10 days following the March 4th split of the PV. This trend is more than likely the incipient stage of a transition to El Nino. The manner in which the subsurface changes manifested at the sea surface, as well as aloft, is clear. This regime was in stark contrast to the DJF pattern and is highly redolent of the La Nina Modoki hemispheric appeal with sinking air centered near the dateline. The shift in the orientation of La Nina as it decayed was captured by JMA EMI guidance. There is an unsurprising resemblance between the March 500mb pattern and the Modoki La Nina 500mb composite, which aligns with the strong Pacific trough regime that led to the record warmth March 9-10. The magnitude of the warmth is quite impressive. This strong Pacific trough period was in fact very comparable to the sequence observed in the wake of the February 2018 analog-warming. This same phenomenon also occurred to a somewhat lesser extent in 2001, as very warm temperatures with highs in the 50s also occurred on February 20th, 2001, which is 10 days subsequent to the February 11th, 2001 PV split. However, the progression of March 2026 differed from 2001 and 2018 in that high latitude blocking failed to materialize within 15-20 days following the warmth, as suggested by research. Thus, as was the case with respect to the March 2-3 PV stretch and accompanying cold intrusion, the arctic outbreak triggered by the next episode of PV elongation on March 18-19th was also brief. One PV Love Elongates SE Towards NE & One Positioned Over Eurasia Following March 4th Split (Image Courtesy Judah Cohen AER Blog) This second major cold outbreak was well forecast given the passage of the MJO through phase 8. Note how quickly the PV lobe again retreated back northward in the absence of blocking to pin it southward. Image Courtesy of Judah Cohen AER Blog The nation was once again left in a mild, fast and zonal flow in its wake, which was the theme of the month. There was simply no mechanism to deliver cold to the northeastern CONUS outside of these episodic stretches of the PV, as the consistent RNA pattern persisted as forecast, albeit less pronounced than the extreme March 2023 west coast troughing. It is important to remain mindful of the fact that having the mean forcing in the MC, as it was throughout most of March, does not prohibit the passage of the MJO through through phase 8 and into the vicinity of the dateline. It merely provides destructive interference with such an occurrence, which limits residence time, amplitude and/or expression throughout the hemisphere. Hence, while there were arctic outbreaks throughout the northeast that coincided with the passage of the MJO through phase 8 during the latter half of the month, they were not accompanied by high latitude and were thus fleeting. This is why the monthly composite is biased warm. Convective forcing simply acts as a means of either constructive of destructive interference, but is not absolutely prohibitive. Incidentally, yet another reversal and split of the PV occurred on March 24th, as this brief arctic outbreak was occurring . This did ultimately result in a round of high latitude blocking during mid April, which was too late for major wintry consequences. Conclusions Drawn From March 2026 The blizzard having occurred in latter February instead of early March coupled with the timing discrepancy with respect to the evolution of the polar domain entailed that the months of February and March were effectively reversed from the 2001 and 2018 analogs. Timing not withstanding, the use of each season as primary analogs for the forecast PV split during the latter portion of the winter season was certainly not without merit. However, due to a combination of timing differences, inconsistencies regarding the precise manner in which the disruption of the PV manifested within the hemisphere, and the stronger Pacific jet relative to the two analogs, the monthly clearly evolved differently than forecast. Although the strong Pacific jet and fast, zonal flow remained prevalent in the absence of high latitude blocking throughout a very mild month of March nation wide, spasmodic stretching of the PV managed to deliver fleeting arctic outbreaks throughout the northeastern US. These represented more abbreviated versions of the arctic intrusions that took place throughout the entirety of the cold season, which Eastern Mass weather identified last summer as a likely occurrence during the coming winter given the expected configuration of both the polar domain, as well as the extra tropical Pacific. This analysis proved very prescient in nature for the season in general, however, during the month of March these intervals of stretching for the polar vortex were mitigated by the zonal flow that predominated the month in the absence of high latitude blocking. This led to a much shorter duration of wintry interludes throughout the northeastern US relative to the the DJF meteorological wintery period, which biased the mean much warmer. These fleeting arctic invasions did act to effectively relegate the exotically warm departures to the southwestern third of the nation in the monthly mean, despite the fact that said colder infiltrations were short-lived owed to said dearth of blocking. The month was ostensibly poised to deliver an active grand finale to the winter season considering it featured two splits of the PV and an MJO progression through phase 8 in a similar fashion to that of March 2001. However, the inability of the cold to persist as it did throughout the meteorological winter season in the absence of high latitude blocking amid the fast, zonal flow was owed to the failed February zonal wind reversal working in concert with the erosion of La Nina from the east. This is undoubtedly why the month ended up so mild, which is risk that was identified in the winter outlook last fall. Winter 2025-2026 Conclusions & The Duality of Forecasting Error Proper Mindset There should be two goals for any seasonal forecasting endeavor, which is applicable to any effort in life, to be frank. Both a high degree of proficiency, as well as a mindfulness of an avenue for improvement with the inherent knowledge that while perfection is an illusive concept, the pursuit for perfection is very real. The reality is that the 12th annual Eastern Mass Weather seasonal forecasting effort entitled Winter 2025-2026 Offers Return to Normalcy was a resounding success. It utilized a multifarious approach grounded in copious research that emulated ensemble forecasting in the plotting of precisely how and why winter 2025-2026 would deviate from the trend of the past decade. Polar, solar, QBO, extratropical Pacific, El Nino Modoki, weak La Nina and east-based La Nina composites all in agreement. Seven seasonal analog composites operating as individual ensemble members, all yielding the same, precise outcome, yet the actual operational 500mb DJFM forecast composite was slightly different and more flawed. Although the Eastern Mass Weather forecast supported a return to more climatologically average temperatures and snowfall across the region, the focus of old man winter's ire was directed more towards the intramountain west, as opposed to the northeast. The was due to the orientation of the PV channeling cold in a more SW to NE fashion versus NW to SE. While this was a rather subtle inconsistency, it did in fact represent a flaw that biased the forecast too warm in the northeast, while ironically enough, the largest error of the entire seasonal effort biased the month of March significantly too cold. Here in lies the duality of the Eastern Mass Weather forecasting error for winter 2025-2026, which was rooted in the struggle as to how to incorporate the concept of climate change into modern seasonal forecasting efforts. How Climate Change Should be Applied to Seasonal Forecasts The reality is that major polar disruptions are very fickle and vary with regard to how they ultimately evolve, which is why the failure of the February zonal reversal to materialize, and thus trigger major high latitude blocking was explicitly identified as a warmer risk for the month of March, and even potentially the season, both last fall and last month. "March should have a -NAO oriented MC deviation similar to that of March 2023, albeit with a less pronounced RNA, which may prove more favorable for a major east coast winter storm. Perhaps something more akin to March 2018: However, the relentless modern Pacific jet will need to be tempered somewhat in order to rival this month in terms of snowfall". Eastern Mass Weather 11-10-2025- The emboldened excerpt at the conclusion of the excerpt from last fall's winter outlook is largely why this warmer and reduced snowfall risk was identified for the month of March, especially in the absence of ample high latitude blocking, and to a lesser extent even if it had materialized. Recall the trend for a faster Pacific jet over the past few decades as a byproduct of climate change that was referenced both near the outset of this writing, as well as in the winter outlook issued on November 10th. Winter 2025-2026 continued this trend, with a very strong northern jet and minimal STJ contribution, which was undoubtedly the reason for the great national precipitation deficit. A stronger jet underscores the importance of meridional flow to maintain any cold, which was largely present from December through February, however, it became more zonal following the failure of the February reversal of the polar zonal winds to materialize as expected, which is when the warmth flooded west. Here is the 200mb jet for the meteorological winter period of December 1 through February 28th (left) versus the jet for the month of March (right). The jet clearly grew much stronger during the month of March as heights lowered in the vicinity of Alaska and much of the polar domain (left). Additionally, it also had less of a meridional component, feeding directly off of the Pacific versus more of a polar feed from Siberia and Alaska due to greater poleward Aleutian ridging during meteorological winter (right). The impact on the resultant pattern was very evident. It rapidly eroded any extension of the PV southward near and beyond the ides of March, and continued to destructively interfere with any such meridional perturbations within the flow, even as the MJO entered phase 8 at a reasonably strong ample amplitude before weakening. Note how amplified the pattern was during meteorological winter as a byproduct of a weaker jet and more high latitude blocking, which allowed cold to bleed southeast and into northeastern US, while the warmth to the west and southwest was consistently held at bay. The difference is apparent versus the fast, zonal flow throughout a month of March, which largely trapped the cold in Canada save for a few instances in which the PV stretched to allow for brief arctic intrusions. Here is a juxtaposition of this past March with March 2018, which is very illuminating in that it portrays how much stronger the Pacific jet was this past March (right) relative to 2018 (left). The polar jet during March 2001 was weaker than both 2026 and 2018, which is not surprising given the aforementioned multidecadal trend. Accordingly there was a great deal of high latitude blocking with below normal temperatures throughout the northeast. The essence of the duality of the seasonal forecasting error for winter 2025-2026 is that the forecast was made under the presumption that climate change should be categorically factored into the forecast at any given locale, which biased the DJFM period too warm over the northeastern US, while the misdiagnosis of the stratosphere biased the forecast for the month of March too warm. The reality is that the impact of climate change should be viewed from the perspective of constructive interference versus destructive interference in much the same manner as the MJO, or any other convective process or hemispheric telconnection is considered. Instead, Eastern Mass Weather weighted the Pacific trough analog pattern of 2001-2002, which intended to denote the +TNH precursor pattern in January, too heavily out of deference to the trend of the past decade of which climate change is undoubtedly a factor. Note the similarity of the DJFM forecast (left) composite to the 2015-2023 composite (right). The forecast was essentially compromise between this, which proved highly accurate: And the trend of the decade, which provided pause despite an overwhelming consensus, on the heels of recent failed efforts that largely neglected to consider climate change. There are no absolutes in forecasting and every rule is capable of being overwhelmed by a more prominent driver under the right circumstances. The reality is that climate change has loaded the dice towards warmth at any given locale, and said warmth will be accentuated and expanded relative to seasons of the past. However, areas of lower atmospheric heights (cold), albeit shrinking, do still exist and can still manifest at any given locale under the right set of circumstances. As it Turns out, Eastern Mass Weather correctly identified those set of circumstances for the northeastern CONUS prior to winter 2025-2026. The postulation that changes were afoot, and that the eastern US would no longer be the focal point for warmth as it had for the past decade was in fact validated, albeit the jet remained strong and MC MJO phases were still favored. However, the mistake was in curtailing and modifying the degree of warmth in the east, poorly diagnosed late season stratosphere not withstanding. The key moving forward is not to practice an aversion to forecasting cold and snow at any given locale in the absolute sense, but rather to maintain an understanding that it's somewhat less likely than in today's than it was in yesterday's climate given the era of expanding ridges and shrinking troughs. This a byproduct of tendency for climate change to constructively interfere with mechanisms that drive warmth and elevate atmospheric heights, rather than prohibit the existence of cold or lower heights in the absolute sense at any given locale. Key questions moving forward will be how much resistance does the MJO encounter when traversing outside of the MC, and does the Pacific jet remain prohibitively strong when other hemispheric drivers destructively interfere. The answer to these questions will dictate winter's ceiling in the future as climate change continues to evolve, and what exactly constitutes the new "normal". FINAL GRADE: A-

Be back now...hard at work on post season analysis. Just complete.

0.18" overnight. 0.63" for the month.

I'm enjoying the cooler weather because the humidity is on the approach. I will say, it could be warmer, but I know what that means around here....all or nothing. 94/72 or 66/41. No in-between...UGH