donsutherland1

January started with readings averaging above normal. The first week of the month will likely average 5° or more above normal across much of the region. A short-duration cold shot is possible late in the first week of January into part of the second week. This cold shot could provide a window of opportunity for at least some snowfall in the region and especially across central/upstate New York and New England. Afterward, a tendency for ridging with warmer than normal temperatures prevailing will likely develop during the latter part of the second week of the month and persist through mid-month. Based on the forecast strongly positive AO, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first 10 days of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables). Such a scenario does not preclude the possibility of a light snow event across parts of the region during this timeframe, particularly during the January 6-9 period. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was +0.4°C for the week centered around December 25. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.27°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was -7.16 today. Today, the preliminary Arctic Oscillation (AO) figure was +3.653. This is the highest figure since December 23, 2016 when the AO was +3.807. No significant stratospheric warming event appears likely through January 10, but a temporary period of warming will very likely develop in the upper stratosphere and approach or reach 5 mb toward the end of the first week of January. Wave 2 activity will remain relatively muted following the first week of the month. Overall, most of the stratosphere is forecast to remain cold on the EPS. On December 31, the MJO was in Phase 8 at an amplitude of 0.756 (RMM). The December 30-adjusted amplitude was 1.069. Since 1974, there were five cases when the MJO was in Phase 6 at an amplitude of 1.500 or above during the December 20-31 period, as has been the case this year. The temperature anomalies were closely tied to how much time the MJO spent in Phase 8 during that timeframe. The mean temperature for January 1-15 for cases with more than 5 such days was 29.0° in New York City. The mean temperature for those with 5 or fewer such days was 36.1°. The overall 1981-2019 mean temperature for January 1-15 is 33.8°. January 2019 will very likely fall into the latter, warmer subset. At the start of January, based on sensitivity analysis applied to the latest guidance, there was an implied 70% probability that New York City would have a warmer than normal January. Such a probability is exceptionally high for the start of a monthly period.

IMO, today's political leaders lack the courage, foresight, and capacity to take on big problems. They are terrified of challenges, pessimistic about the human capacity to innovate, and tied to the status quo. Past generations took on big problems over shot time frames when the existing technology did not yet exist. That's the story of the Manhattan and Apollo Projects. Had today's political leaders been in positions of authority during either project, both would never have been attempted. The world would likely be a vastly different place for such failure to lead.

That's so far in the future, there's essentially no skill with any dynamical or statistical tool. That doesn't mean it can't happen, but such an outcome is far from a high confidence one.

Ok. That makes more sense. Let's hope that doesn't happen.

It does. Some MJO passages through the Maritime Continent (Phases 4 and 5) at very high amplitude have produced a bout of near-record to record warmth. So one or two days where the temperature spikes is certainly within the realm of possibility.

Phases 4-5 by around 1/10 is what many here have been talking about for days. There is very strong support on the guidance for such a move and at high amplitude. It's the reason the development of a period of ridging near 1/10 and for at least a week is now likely as per the major global operational models and their ensembles.

New Year, New Decade, Old Story... Despite the change in calendar to a new year and new decade, time seems stuck. The region started the first morning of the 2020s with above normal temperatures, much as 2019 concluded. Morning low temperatures into southern New England were generally several degrees above freezing. The week ahead looks mild overall, even as some cooler air could arrive late in the period. There remains some possibility of a light snow event in parts of the Middle Atlantic region and maybe a light-to-moderate event in parts of New England afterward before a warmer pattern reasserts itself. Based on the sensitivity analysis applied to the latest guidance, there is an implied 64% probability that the January 1-7 temperature in New York City will average 40.0° or above. 74% of the 23 prior cases went on to record a warmer than normal January and nearly half had a monthly mean temperature of 35.0° or above.

December concluded with widespread warm anomalies. Despite having a monthly temperature anomaly of 2.7° below normal on December 21, New York City finished with an anomaly of 0.8° above normal. Snowfall was also generally below normal in much of the coastal plain and larger Middle Atlantic region. The preliminary December 2019 temperature anomalies for select cities were: Baltimore: +3.2°, Boston: +2.5°, Islip: +1.2°, New York City: +0.8°, Newark: +1.1°, Philadelphia: +1.2°, and Washington, DC: +2.4°. Through December 31, total snowfall in New York City was 2.5". In Philadelphia, it was 0.1". In Washington, DC, it was 0.4". Since 1888, there were 29 prior cases when seasonal snowfall through December 31 was less than 1" in Philadelphia and Washington, DC and less than 4" in New York City. Mean seasonal snowfall amounts by the end of the winter were: New York City: 20.6" (median: 15.1"); Philadelphia: 16.1" (median: 13.4"); and, Washington, DC: 12.1" (median: 9.5"). In New York City, 59% of such winters wound up with less than 20" snowfall, but an equal share wound up with less than 10" and more than 40". In Philadelphia, 66% of such winters had less than 20" snowfall. In Washington, DC 79% of such winters recorded less than 20" snowfall. January will begin on a generally mild not with the first week averaging 5° or more above normal across much of the region. A short-duration cold shot is possible late in the first week of January into part of the second week. Afterward, a tendency for ridging with warmer than normal temperatures prevailing could develop during the latter part of the second week of the month. Based on the forecast strongly positive AO to start January, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first 10 days of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables). Such a scenario does not preclude the possibility of a light snow event across parts of the region during this timeframe, particularly during the January 6-9 period. 2019 was, by far, the warmest year on record in Utqiagvik (formerly Barrow) with an annual mean temperature of 20.9°. The previous record was 18.9°, which was set in 2016. Anchorage also capped off a record warm year with a record high daily temperature of 46°. The previous record was 44°, which was set just last year. The previous warmest year on record was 41.5°, which occurred in 2016. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.6°C for the week centered around December 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.12°C and the ENSO Region 3.4 anomaly has averaged +0.56°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was -4.00 today. Today, the preliminary Arctic Oscillation (AO) figure was +2.726. The AO has now risen 5.1 sigma in 4 days and nearly 5.5 sigma in 5 days. The preliminary December average was +0.391 (55% days positive and 45% days negative). No significant stratospheric warming event appears likely through January 9, but warming will very likely develop in the upper stratosphere and approach or reach 5 mb toward the end of the first week of January. Wave 2 activity will remain relatively muted at 30 mb through most of the first week of January, but a moderate Wave 2 hit could occur at or above 10 mb leading to the upper stratospheric warming. Overall, most of the stratosphere is forecast to remain cold through the first week of January on the EPS. However, the upper stratospheric warming will need to be watched for possible downward propagation. On December 30, the MJO was in Phase 7 at an amplitude of 1.069 (RMM). The December 29-adjusted amplitude was 1.259. Since 1974, there were five cases when the MJO was in Phase 6 at an amplitude of 1.500 or above during the December 20-31 period, as has been the case this year. The temperature anomalies were closely tied to how much time the MJO spent in Phase 8 during that timeframe. The mean temperature for January 1-15 for cases with more than 5 such days was 29.0° in New York City. The mean temperature for those with 5 or fewer such days was 36.1°. The overall 1981-2019 mean temperature for January 1-15 is 33.8°. January will likely be warmer than normal across the Middle Atlantic region and southern New England. The likely anomalies will range from 1.5° to 2.5° above normal (around 2.4°above normal in New York City).

During the afternoon, clouds broke for sunshine on occasion. The temperature topped out at a mild 44°. Three photos, one of which shows the aftermath of yesterday’s pounding waves. At the end, winds gusted past 50 mph yesterday.

Using the base normal figure skews things, as 2.4 degrees above normal was once around freezing, meaning a greater tendency of snowfall. Using temperature averages is more meaningful. January Mean: 34.0-34.9: Mean: 7.5"; Most: 27.9", 2016 January Mean: 35.0-35.9: Mean: 4.5"; Most: 13.3", 1964 January Mean: 36.0-39.9: Mean: 2.8"; Most: 7.9", 2017 January Mean: 40.0 or above: Mean: 1.5"; Most: 6.5", 1937 That data is from Central Park.

Some quick morning thoughts on January: 1. The AO is now rising sharply. It has increased by more than 5 sigma over the past 4 days. It is forecast to remain strongly positive into mid-month. 2. The EPO is currently positive and rising. It could go neutral during the second week of the month. EPO+/AO+ patterns are typically the warmest in January. Such warmth is often amplified when the SOI is negative. 3. There is strong consensus on the guidance that the MJO will move into the Maritime Continent phases at high amplitude. All said, the first week of January could have a mean temperature at or above 40 degrees in NYC and the first half of the month, could be much warmer than normal. Any snowfall during the brief window as a trough swings across the region from late in the first week of January to the middle of the second week will likely be light. No significant snowfalls (6" or above) are likely for the Middle Atlantic region. Central and upstate New York and New England would have a better chance at significant snowfall. Ridging with above to occasionally much above normal temperatures should redevelop around January 10 +/- a few days and could predominate for at least a week and possibly longer. My final guess is that NYC will probably have a January temperature anomaly of 2.4 degrees above normal.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA 2.2 2.4 1.3 1.5 1.0 0.0 -1.0 -1.5 0.4

The storm that brought the year's last significant precipitation to the region is now departing. Steady precipitation was falling across eastern Long Island and into eastern New England. Precipitation amounts were in line with expectations. Through 8 pm, amounts included: Allentown: 0.75"; Baltimore: 0.83"; Boston: 1.17"; Bridgeport: 1.39"; Harrisburg: 0.69"; Islip: 1.12"; New York City: 0.99"; Newark: 0.97"; Philadelphia: 0.99"; Poughkeepsie: 1.12"; Providence: 1.44"; and, Scranton: 0.50". Through December 29, monthly anomalies for select cities were: Baltimore: +2.3°, Boston: +2.0°, Islip: +0.7°, New York City: +0.4°, Newark: +0.6°, Philadelphia: +0.7°, and Washington, DC: +1.6°. January will begin on a generally mild not with the first week averaging 5° or more above normal across much of the region. A short-duration cold shot is possible late in the first week of January into part of the second week. Afterward, a tendency for ridging could develop during the latter part of the second week of the month. Based on the forecast strongly positive AO to start January, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first 10 days of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables). Such a scenario does not preclude the possibility of a light snow event across parts of the region during this timeframe, particularly during the January 6-9 period. Despite the development of a sustained colder than normal temperature regime, Utqiagvik (formerly Barrow) is nearing the end of its warmest year on record. 2019 will likely conclude with a mean temperature of 20.9°. The existing record is 18.9°, which was set in 2016. Currently, 2017 ranks as the second warmest year and 2018 ranks as the fourth warmest year. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.6°C for the week centered around December 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.12°C and the ENSO Region 3.4 anomaly has averaged +0.56°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was +1.09 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.389. No significant stratospheric warming event appears likely through January 8, but warming will very likely develop in the upper stratosphere and approach or reach 5 mb toward the end of the first week of January. Wave 2 activity will remain relatively muted at 30 mb through most of the first week of January, but a moderate Wave 2 hit could occur at or above 10 mb leading to the upper stratospheric warming. Overall, most of the stratosphere is forecast to remain cold through the first week of January on the EPS. However, the upper stratospheric warming will need to be watched for possible downward propagation. On December 29, the MJO was in Phase 7 at an amplitude of 1.262 (RMM). The December 28-adjusted amplitude was 1.265. Since 1974, there were five cases when the MJO was in Phase 6 at an amplitude of 1.500 or above during the December 20-31 period, as has been the case this year. The temperature anomalies were closely tied to how much time the MJO spent in Phase 8 during that timeframe. The mean temperature for cases with more than 5 such days was 29.0° in New York City. The mean temperature for those with 5 or fewer such days was 36.1°. The overall 1981-2019 mean temperature for January 1-15 is 33.8°. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that December will wind up warmer than normal in New York City with a monthly mean temperature near 38.4°. At present, a warmer than normal January appears likely in the region.

Thanks for sharing this.

Unfortunately, yes.

The study indicates that on account of the expanding pool of warm waters, the MJO is spending somewhat more time in the Maritime Continent phases. This would make sense given the ocean-atmosphere-convection linkage.

A quick note on teleconnections and Washington, DC's 6" or greater January snowstorms (1950-2019): AO-/PNA+: 67% AO+/PNA-: 0% (biggest: 3.9") AO-: 80% PNA+: 87% NAO-: 67% n=12 If one broadens the pool to include 4" or greater snowstorms (n=22), the numbers change very little for all but the NAO: AO-/PNA+: 64% AO+/PNA-: 0% AO-: 77% PNA+: 86% NAO-: 55% Note: All of the 10" or greater snowstorms occurred with an AO-/PNA+

There may be reason for concern. Some recent scientific literature: https://www.nature.com/articles/s41586-019-1764-4

It's due to two major assumptions: 1. The MJO's progression away from the Maritime Continent and through Phase 6 into Phase 7 2. A weakening of the strong polar vortex. There are a number of cases where a super strong polar vortex in early January weakened with sustained blocking occurring in late January and/or February None of this is cast in stone, but there's enough reason to refrain from canceling winter (even if Ji has already done so).

The weakening IOD should reduce interference with the MJO. That should allow it to progress in more typical fashion. The forecast shift to the Maritime Continent (Phases 4-5) is real and the ridging forecast beyond 240 hours is increasingly likely to verify. Absent the MJO, that's still what one would expect given the forecast state of the teleconnections. And if things aren't miserable enough, there's the risk that the EPS weeklies could deliver another serving of misery a little later today. However, this does not mean that it is time to cancel winter. If things work out, the potential for a pattern change for colder and snowier weather could increase during late January. February might offer the best chance for meaningful snowfall in the Middle Atlantic region. We'll see, as a lot of variables are involved, but things should eventually get better all other things being considered.

The AO is particularly important for the Middle Atlantic region and the NAO also carries weight. New England does much better thanks to its higher latitude and has had significant snowstorms even when the AO was in excess of +2.000 in January. The following from my nearly daily discussion in the NYC forum holds true for the MD-DCA-VA areas: Based on the forecast strongly positive AO to start January, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first week of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables). Some of the newer AO forecasts keep the AO at +2.000 or above through January 10. If so, that development could adversely impact Mid-Atlantic significant snowfall prospects beyond the first week of January.

That was merely an observation. The main point is that one should not use 1978 as an analogy for the forecast Phases 4-5 MJO in the extended range.

Two photos along the Long Island Sound from early this afternoon. The temperature was 41° with drizzle. The wind was gusting around 40 mph by the water.

During theJanuary storm, the MJO was moving from Phase 3 into Phase 4 at a super high amplitude. During the February blizzard, it was in Phase 7 and headed for Phase 8 with an exceptional AO block.

MJO forecast update: The GEFS now shows the MJO moving into the Maritime Continent phases at high amplitude. It was the last hold-out. The main caveat is that such MJO forecasts at the timescale involved are still low-skill forecasts. It remains to be seen whether the EPS weeklies will deliver a fresh dose of misery later in the day.