donsutherland1

Four photos from today’s rainstorm during which White Plains received 0.61” in an hour and 1.20” through 5 pm:

30 year averages are rising. It has been exceptionally warm in Europe and the warmth is likely to continue for some time.

Morning thoughts... At 9 am, rain was moving into the New York City Metro Area. As of 9 am, rainfall totals included: Baltimore: 1.47"; Philadelphia: 0.59"; and, Washington, DC: 1.33". A widespread 0.50"-1.50" rainfall with some locally higher amounts remains on track for the region. Meanwhile, ENSO and teleconnections developments have continued to evolve toward a scenario where a milder February may now be more likely than a colder one. During February, the ENSO Region 3.4 anomaly will likely average 0.00°C to +0.75°C. The most recent 6-week moving average is +0.52°C. During February, both the AO and EPO will likely remain predominantly positive. The AO has been positive on 75% days this winter to date, including 68% during which it was +1.000 or above. This ENSO-teleconnections combination typically favors a warmer than normal February. Late yesterday (18z GEFS) and overnight (0z EPS/0z and 6z GEFS) now show the trough shifting to the west and potential ridge development in the East near the end of their timeframes. In addition, the CFSv2 has been steadily evolving toward a milder solution in the East. Most recent CFSv2 forecasts:

Temperatures will likely run above normal through the remainder of January and into the start of February. Little or no snow is likely in New York City, Newark, Philadelphia, and Washington, DC for the remainder of the month. Colder air could return late in the first week in February or just afterward. As long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 such storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall will likely exist for central and upstate New York and central and northern New England. Boston would have a higher probability of receiving a moderate or significant snowfall than Baltimore, New York City, Newark, Philadelphia, and Washington, DC. A storm will likely bring 0.50" to 1.50" rain to Washington, DC to Boston tomorrow into perhaps part of Sunday. A moderate snowfall with perhaps some locally significant amounts could occur across upstate New York, northern New England, and parts of southern Ontario (north and east of Toronto). The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C: ENSO R1+2 Anomaly < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates) ENSO R1+2 Anomaly < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates) ENSO R1+2 Anomaly > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates) ENSO R1+2 Anomaly > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates) February 1981-2019: NYC: 35.8°; Philadelphia: 36.0° The SOI was +10.32 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.237. No significant stratospheric warming event appears likely through February 1. Wave 2 activity could increase near the end of January leading to some warming of the upper stratosphere. Overall, most of the stratosphere is forecast to remain cold on the EPS into the start of February. On January 23, the MJO was in Phase 7 at an amplitude of 1.812 (RMM). The January 22-adjusted amplitude was 2.109. The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. The MJO moved into Phase 7 on January 20. Based on sensitivity analysis applied to the latest guidance, New York City has an implied near 100% probability of a warmer than normal January. The monthly mean temperature could finish near 39.0° in New York City. That would surpass the 38.6° monthly temperature from 1949 to make 2020 the 9th warmest January on record.

That was the control. The control is, to be charitable, not the best guide for such forecasts.

Some evening thoughts... Based on the latest teleconnections forecasts, it continues to appear that the pattern will remain largely unfavorable for moderate or significant snowfalls in the Philadelphia to New York City area through the end of January. There is little uncertainty about Saturday's storm. That system will bring rain to the big cities of the Middle Atlantic region. The probability of widespread moderate or significant snowfall across central New York State and central New England has fallen. Moderate to locally significant amounts remain possible in parts of upstate New York and northern New England. The guidance is in good agreement about this outcome. Another storm could impact the region near the start of February. As the prospect of a more neutral AO has fallen over the past day, so has the probability of a moderate or significant snowfall on the Mid-Atlantic region's coastal plain. Given the latest ensemble forecast (+1.000 or above), a significant snowfall for such cities as Philadelphia and New York appears unlikely. During the January 15-February 15, 1950-2019 period New York City saw 56 storms bring 4" or more snow to New York City. Just 13% of such storms occurred when the AO was +1.000 or above and 9% occurred when the AO was +1.500 or above. For Philadelphia, there were 45 such storms. The respective percentage for an AO of +1.500 or above was 13%, and for an AO of +1.500 or above, it was 11%. The 12z ECMWF's outlook showing little or no snow for New York City and Philadelphia through the remainder of January is consistent with historic outcomes associated with the current strongly positive AO. All said, it still appears that seasonal snowfall through January will likely be less than 6" in New York City and less than 1" in Philadelphia. Current totals to date are 4.8" and 0.3" respectively. Today is also Atlanta's record 675th day without even a trace of snow. Colder air could arrive late in the first week of February or during the second week of the month as a trough develops in the East.

Under partly sunny skies, temperatures rebounded into the middle and upper 40s across the northern Mid-Atlantic region. Temperatures will likely run above normal through the remainder of January and into the start of February. Colder air could return late in the first week in February or just afterward. As long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 such storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall will likely exist for central and upstate New York and central and northern New England. The pattern could begin to grow more favorable for snow on the coastal plain during the beginning of February should the Arctic Oscillation (AO) fall toward neutral levels. Before then, a storm could bring 0.50" to 1.50" precipitation, mostly or all rain, to Washington, DC to Boston this weekend. A moderate snowfall with some locally significant amounts could occur across upstate New York, northern New England, and parts of southern Ontario (north and east of Toronto). The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C: ENSO R1+2 Anomaly < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates) ENSO R1+2 Anomaly < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates) ENSO R1+2 Anomaly > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates) ENSO R1+2 Anomaly > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates) February 1981-2019: NYC: 35.8°; Philadelphia: 36.0° The SOI was +0.05 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.494. Through January 23, the AO has averaged +1.467 for meteorological winter. That's the 5th highest average on record for the December 1-23 period. No significant stratospheric warming event appears likely through January 31. Wave 2 activity could increase near the end of January. Overall, most of the stratosphere is forecast to remain cold on the EPS. On January 22, the MJO was in Phase 7 at an amplitude of 2.108 (RMM). The January 21-adjusted amplitude was 2.045. The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. The MJO moved into Phase 7 on January 20. Based on sensitivity analysis applied to the latest guidance, New York City has an implied near 100% probability of a warmer than normal January. The monthly mean temperature could finish near 39.0° in New York City. The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased to near 65%. The 10th warmest January occurred in 1906 with a monthly mean temperature of 38.4°. The 9th warmest January was January 1949 with an average temperature of 38.6°. Boston, which set a January record high temperature of 74° on January 12, has had an even warmer January relative to climatology. Boston could have among the five warmest Januaries on record. The 5th warmest January there was January 2002 with a mean temperature of 36.7°. The 4th warmest January was 37.4° in 1937.

After a cold start, especially outside the City where temperatures fell into the teens with some single digits (Danbury reported a 6° low and Poughkeespie had a minimum temperature of 7°), temperatures rose into the upper 30s in the region. Temperatures will likely run above normal through the remainder of January. However, a mild finish to a very warm January does not mean that February will likely be warmer than normal. The coefficient of determination for New York City between the January and February temperatures is just 0.07. Records go back to 1869. Colder air could return during or just after the first week in February. As long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 such storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall will likely exist for central and upstate New York and central and northern New England. The pattern could begin to grow more favorable for snow on the coastal plain during the beginning of February should the Arctic Oscillation (AO) fall toward neutral levels. Before then, a storm could bring 0.50" to 1.50" precipitation, mostly or all rain, to Washington, DC to Boston this weekend. A moderate snowfall with some locally significant amounts could occur across central and upstate New York, central and northern New England, and parts of southern Ontario. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C: ENSO R1+2 Anomaly < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates) ENSO R1+2 Anomaly < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates) ENSO R1+2 Anomaly > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates) ENSO R1+2 Anomaly > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates) February 1981-2019: NYC: 35.8°; Philadelphia: 36.0° The SOI was -6.17 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.544. No significant stratospheric warming event appears likely through January 30. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS. On January 21, the MJO was in Phase 7 at an amplitude of 2.044 (RMM). The January 20-adjusted amplitude was 2.153. The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. The MJO moved into Phase 7 on January 20. Based on sensitivity analysis applied to the latest guidance, New York City has an implied near 100% probability of a warmer than normal January. The monthly mean temperature could finish near 39.0° in New York City. The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased to just over 60%. The 10th warmest January occurred in 1906 with a monthly mean temperature of 38.4°. The 9th warmest January was January 1949 with an average temperature of 38.6°.

For early February reference, below are the 500 mb height anomalies for snowstorms that brought 6" or more snow to Boston, New York City, and Philadelphia (all 3 locations) during the February 1-15, 1950-2019 period. Storms that commenced prior to February 1 or continued after February 15 are excluded. One typically found a Greenland-Hudson Bay block and/or a PNA+ ridge coupled with a trough in the East. The variation on a case-by-case basis should also be noted.

Some quick morning thoughts... It has been a warm and dry January so far in the Mid-Atlantic region. Through January 21, precipitation in New York City is 1.06" (1.47" below normal) and in Philadelphia it is 1.00" (1.05" below normal). The combination of limited precipitation and limited cold has led to very low monthly snowfall amounts so far (2.3" in New York City and 0.2" in Philadelphia). A storm will likely bring a moderate to perhaps significant amount of precipitation (0.50" - 1.50") to the region this weekend, but the major cities of the Mid-Atlantic region will likely see little or no snow. Philadelphia will likely finish January with less than 1" snow for the season and New York City will likely finish with less than 6". As January nears an end, there remains no credible evidence of the kind of "shock" that could bring significant change to the hemispheric circulation. The Polar Vortex is likely to remain strong with a predominant positive AO. The EPO looks to remain positive. The stratosphere looks to remain cool. As a result, February could begin on a mild note. Cold could still arrive near the end of the first week of February or just afterward, but such cold likely won't be severe. At the same time, the risk that February as a whole could wind up on the warm side of normal has increased. That's not yet the most likely outcome, but it's a scenario that cannot be dismissed.

Warmer conditions will likely develop starting tomorrow. No exceptional warmth appears imminent, but readings will likely run above normal through the remainder of January. A mild finish to a very warm January does not mean that February will likely be warmer than normal. The coefficient of determination for New York City between the January and February temperatures is just 0.07. Records go back to 1869. Colder air could return during or just after the first week in February. As long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 such storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall will likely exist for central and upstate New York and central and northern New England. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C: ENSO R1+2 Anomaly < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates) ENSO R1+2 Anomaly < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates) ENSO R1+2 Anomaly > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates) ENSO R1+2 Anomaly > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates) February 1981-2019: NYC: 35.8°; Philadelphia: 36.0° The SOI was -3.62 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.483. No significant stratospheric warming event appears likely through January 29. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS. On January 20, the MJO was in Phase 7 at an amplitude of 2.152 (RMM). The January 19-adjusted amplitude was 2.644. The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. The MJO moved into Phase 7 on January 20. Based on sensitivity analysis applied to the latest guidance, New York City has an implied near 100% probability of a warmer than normal January. The monthly mean temperature could finish near 38.5° in New York City. The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased to just over 50%. The 10th warmest January occurred in 1906 with a monthly mean temperature of 38.4°. The 9th warmest January was January 1949 with an average temperature of 38.6°.

IMO, the boundaries you suggest are good. In fact, there are some people who live in Pike County but commute to NYC despite the distance. Also, I think a fuller discussion, even when New York City is likely to receive less than an inch of snow is better than a more limited one. I hope you continue posting as you currently post. The discussions are invaluable.

The March 2019 events were two separate ones.

6.4" fell on November 15, 2018 creating significant travel problems, as the City was caught unprepared for the snow.

It depends on the kind of ENSO event. A strong basin-wide event would likely lead to warmth absent strong blocking.

In general, an El Niño leads to a more active subtropical jet stream and a northward displacement of the polar jet stream. That's the general idea, but differences exist, because differences in anomalies in each of the El Niño Southern Oscillation (ENSO Regions) have an impact. Major ENSO Regions, from East to West, are Region 1+2, Region 3, Region 3.4, and Region 4. Often, when the El Niño is Central Pacific-based (Region 3.4 anomaly > Region 1+2 anomaly), the subtropical jet is active, but the polar jet is not displaced as far to the north as would be the case in an East-based or basin-wide El Niño event. Therefore, one often sees above average snowfall in the Northeast. Here's a useful link that explains El Niño: https://www.climate.gov/news-features/understanding-climate/el-niño-and-la-niña-frequently-asked-questions Here's a good link to take a look at El Niño impacts: https://www.climate.gov/news-features/understanding-climate/climategovs-most-requested-el-niño-and-la-niña-images One should keep in mind, other variables can interact with El Niño producing different outcomes. For example, extreme Atlantic blocking during a strong El Niño during winter 2009-10 led to a colder than normal winter overall with very high seasonal snowfall.

Beyond two weeks, they typically don't fare better than climatology.

For the second time this month, the temperature fell to 20° in New York City. Tonight, readings approach and possibly fall just below 20° in Central Park. Following another chilly day tomorrow, warmer conditions will likely develop. Somewhat colder air could return during the closing days of January, but the risk that January could end on a mild note has increased. A mild finish to a very warm January does not mean that February will likely be warmer than normal. The coefficient of determination for New York City between the January and February temperatures is just 0.07. Colder air could return during or just after the first week in February. In addition, so long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall would likely exist for central and upstate New York and central and northern New England. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C: ENSO R1+2 < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates) ENSO R1+2 < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates) ENSO R1+2 > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates) ENSO R1+2 > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates) February 1981-2019: NYC: 35.8°; Philadelphia: 36.0° The SOI was +2.93 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.687. No significant stratospheric warming event appears likely through January 28. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS. On January 19, the MJO was in Phase 6 at an amplitude of 2.646 (RMM). The January 18-adjusted amplitude was 2.909. The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. Based on sensitivity analysis applied to the latest guidance, New York City has an implied 99% probability of a warmer than normal January. The monthly mean temperature could finish near 38.0° in New York City. The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased to just over 40%.

Thanks for sharing this interesting research.

Thanks for the kind words. I hope you get the chance to photograph the methane bubbles at some point in the future.

After a morning low temperature of 20°, the temperature remained mainly in the 20s this afternoon before topping out at 31°. Some photos of ice are below:

This morning, the temperature sank to 20° in Central Park. January has yet to see a temperature in the teens. Tonight could be another opportunity for the temperature to push toward the teens in Central Park. Meanwhile, if one looked at the latest teleconnections forecast, the AO is forecast to remain positive to strongly positive through the next two weeks. Nothing has changed there. To date, the AO has averaged +1.464 during meteorological winter. Just to average 0.000, it would have to average -1.867 every day starting tomorrow through February 29. At the same time, the PNA is forecast to "flatline" (perhaps a fitting symbol of Social Media's thinking that Winter 2019-2020 has flatlined, the boredom that has swept online weather communities waiting for winter to reassert itself, or depression from Europe's non-winter to date). Such highly stable PNA regimes have occurred before. One such regime occurred during January 8 through January 24, 1985. During that 17-day period, the PNA averaged +0.930. The standard deviation was 0.057. The lowest PNA figure was +0.852 on January 14. The highest was +1.011 on January 16.

The following are the statistics for NYC's 6" or greater snowstorms (1950-2019): 1/1-31: 20% PNA- 2/1-14: 39% PNA- 2/15-29: 45% PNA- 3/1-15: 57% PNA-

In the wake of yesterday's snowfall, another shot of cold air has moved into the region. However, its stay will likely be short-lived. Warmer conditions will likely develop during the middle of the week. Somewhat colder air could return during the closing days of January, but the risk that January could end on a mild note has increased. A mild finish would represent a big change from the previous scenario where Pacific-driven changes would lead to the development of a colder pattern to continue into the start of February. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.5°C for the week centered around January 8. 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 +0.50°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was +0.24 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.489. No significant stratospheric warming event appears likely through January 27. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS. On January 18, the MJO was in Phase 6 at an amplitude of 2.913 (RMM). The January 17-adjusted amplitude was 3.178. The MJO had spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January. Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. Further, the MJO was in Phase 4 at an amplitude of 2.273 on January 7 with an AO of +4.048. Since 1974, there were three January cases when the MJO was in Phase 4 at an amplitude of 2.000 or above and an AO of +3.000 or above. In all three cases the Week 3-4 period was colder than the Week 1-2 period (smallest change: 2.7° in 1993; largest change 16.8° in 2007). The change in 14-day average temperatures from the above three cases would imply a January 22-February 3 mean temperature of 10°-12° below the January 8-21 mean temperature in New York City. This data implies that the latter two week period as a whole would be colder than normal overall. However, uncertainty about the extended range has increased and a warmer than normal outcome now appears more likely than not (perhaps something closer to the January 1993 outcome even as the week 3-4 outcome will be colder than the week 1-2 period). A very warm first and second half of January does not necessarily mean that February will be warmer than normal. There were five such cases following a January 1-15 mean temperature of 40.0° or above. 1932 and 1998 were warmer than normal in February. 2006 was near normal. 1937 and 1950 were colder than normal. Overall, for New York City, the coefficient of determination between the January and February temperature is just 0.07 (1869-2019). Based on sensitivity analysis applied to the latest guidance, New York City has an implied 99% probability of a warmer than normal January. The monthly mean temperature could finish near 38.0° in New York City. The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased.

To say that New York City and Philadelphia are digging out of their biggest snowstorm of the winter so far would be somewhat of an exaggeration, but not a complete exaggeration. Yesterday's snowfall of 2.1" in Central Park and 0.2" in Philadelphia are both cities' largest snowfall of winter 2019-20. It has been a bleak winter in terms of snowfall across much of the Middle Atlantic region. To add insult to injury, the pattern evolution has become less favorable for meaningful snow through the remainder of January. Even the previously bullish CFSv2 weeklies have now delayed the onset of a cold pattern beyond the first week of February. Should New York City finish January with less than 6.0" total snowfall for the season, winter 2019-20 will join 34 previous cases. The mean snowfall for the remainder of the season during those prior cases was 13.5" and the median was 10.6". The most was 43.0" during winter 1895-96 (30.5" in March). The least was 0.0" in winter 2001-02. In 11 (32%) cases, New York City received 15.0" or more snow during the remainder of winter. In 16 (47%) cases, New York City received less than 10.0" snow for the remainder of winter. In addition, the temperature has yet to fall below 20° this month in Central Park. New York City's minimum January temperature was 20° or above in seven prior years, most recently 2002. Five of those cases went on to record much below normal snowfall in February. Two (1949 and 1993) had somewhat above normal February snowfall (10.7" in both cases). Still, things could be worse. Instead of infrequent but picturesque light snowfalls, the region could be experiencing the non-winter that has gripped Europe throughout the season. Today, the thermometer is again flirting with record high temperatures in parts of Estonia, Finland, and Russia.